nutrition and disease management (Only 5 questions)

Use the attached papers and the reference

>Group A

Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only

and

umami

,sweet

tomato

and rasp

fruit

apple

apple tropical tropical

2 Taste

, dry, sweet

ish

sweet, fruity

bitter, sour

sweet

Juice ID tomato tomato cranberry grape pineapple pineapple grapefruit grapefruit tropical tropical orange orange grape apple

Taste

sour

mount sour bitter little sweet

Juice ID tomato tomato

cranberry apple grapefruit

apple

/lemonade

orange juice grape forest fruit

Taste

,rich in texture

and

, not sweet

sweet sweet bitter, sour

very sweet sour little bit sweet little bit sour

Juice ID

apple

pineapple pineapple

apple juice orange juice orange forest fruit cranberry

Taste

sweet

sweet sweet bitter bitter, sour

sour sour sweet sweet

Juice ID tomato tomato grape cranberry pineapple pineapple grapefruit grapefruit

apple orange orange apple grape

Taste

sweet/tangy sweet sour/bitter

sweet

sour/tangy sweet/tangy sweet/tangy

Juice ID tomato tomato cranberry cranberry tropical tropical grapefruit grapefruit apple tropical orange orange grapefruit apple

Taste

tangy, sweet

Sour, sweet

very sweet

Juice ID Tomato Tomato cranberry

Pineapple

Grapefruit lemon

Orange apple apple

Taste

, sour

a bit tart

, tangy

very sweet very bitter, sour very sour and bitter

Sweet

Sour/tangy

Sweet

Juice ID Tomato Tomato Cranberry

Pineapple pineapple Grapefruit grapefruit Orange Orange

lemon apple apple

Taste

sweet, thick bitter

Juice ID tomato tomato orange apple juice grape pineapple grapefruit grapefruit

juice

cranbery pineapple orange apple grape

Taste

sweet, smooth

thick, sweet sweet, soft sweet, soft

Juice ID tomato tomato orange grape pineapple pineapple grapefruit grapefruit

apple orange juice orange apple apple

Taste

salty

astringant

sweet bitter bitter acidic sweet+bit acidic

bit sweet bit sweet bit sweet

Juice ID tomato tomato grapefruit apple juice

cramberry orange juice pineapple grape apple orange tropical apple

Taste salty salty

sweet sweet

bit sweet bit sweet+bitter sweet+bit bitter sweet

Juice ID tomato tomato cramberry cramberry

pineapple grapefruit grapefruit mango orange

mixed fruits orange apple

Taste

sour very sour and bitter

Juice ID tomato tomato

cranberry pineapple pineapple grapefruit grapefruit orange tropical orange orange apple apple

Taste

sourish sweet

very sweet sour a bit bitter

sour sweet a bit sour sweet a bit sour

Juice ID tomato tomato cranberry cranberry

pineapple grape grape strawberry apple apple orange cranberry grape

Taste Salty very salty Sweet

little sweet

y, little tangy

sweet, fruity

Juice ID Tomato Tomato Cranberry Cranberry

Pineapple Grapefruit Grapefruit

tropical orange orange mango apple

Taste

salty

bitter, sour

sweet, subtle

, fruity

sharp, very sweet

Juice ID Tomato tomato apple grape apple

grapefruit grapefruit pineapple mango blackcurrent orange pineapple apple

Juice A

Juice B

Juice C

Juice D

Juice E

Juice F

Juice G

Student #

Blind + nose clip

blind only

Taste

umami

sweet

dry but sweet

astringic,

bitter

thick, sweet

really sweet,

sour

bitter

acidic

bitter, sour

tangy, sweet

very

sweet, fruity

tangy sweet citric

not sweet, sour

sweet, thick

sweet, astringic

Juice ID

tomato

cran

berry

cranberry

pine

apple

tropical

grape

grapefruit

pineapple

orange

umami, bitter and sweet

umami, thick

astringant

astringic,sweet

Thick, sweet, fruit

bitter, tangy

bitter, fruity

sweet, tangy

not too sweet

thick and sweet

sweet and watery

sour,rich in textur

sharp taste,very concentrated,alty

sour,tangy

mount sour

mount

sour,

little sweet

little sour

very sour

very bitter

very sour and bitter

sour,little sweet

little bit sour

pineaple

orange juice

concentrated orange juice

forest fruit

lemon

Salty

little

bit sweet

salty

Sour

mostly sour,

little bit sweet

fairy

bitter and sour

very sweet

sour and sweet

Tomato

Toamto

apple juice

grapefruit juice

grape fruit juice

grape juice

salty/meaty/earthy

salty/earthy

very tangy

sweet/tangy

tangy/appley

blackcurrent

salty/heavy flavour

salty/sour

sour/tangy

sour/bitter

bitter/sour/tart

sweet/sour

sweet/sourkick

Salty,earthy,slightly sweet

salty a little sweet

tangy/sour

sour,slightly sweet, astringic

tangy,sweet

very bitter, sour

bitter, sour after taste

Sour, sweet

very sweet slightly sour

Sour/tangy

very sweet a little sour

Cranberry

Pineapple

Grapefruit

orange and lemon

Orange

Very salty

very salty

Sour, bitter

Sour bitter after taste

Sweet

Sweet, Sour

more sour than sweet

Sweet, sugary and bitter

Plum

lemon/lemonade

thick, intense, not sweet

SALTY, thick

LITTLE BIT SWEET, bit thick

soft ,

sour sweet

little bit sour, more sweet

very bitter, soft

little sour, strong taste

sour, soft

sweet, soft

sofe, sweet

sweet, smooth

sweet, sour, soft

cranbery

concentrated, little thick, little sour

thick, concentrated, sour

little sweet, smooth

sweet, smooth ,

very sweet, soft

bitter, smooth

very bitter, smooth

sweet, soft, little sour

smooth, sweet

soft, sweet

mango

salty+sour

astringant, dry, sweet

bit

sweet+bit acidic

bit sweet+bit acidic

strawberry

cramberry

bitter+bit sweet

bit sweet+bitter

bitter+salty

bit acidic+bitter

sweet+bit bitter

bit bitter+sweet

peach

mixed fruits

sour-sweet bitter peperry

salty bell pepper and sweet

bland

sweet light

most sweet

sweet tropical

mild sour

sour and sweet mix

sour but more sweet

sourish sweet

sweet a bit sour

sweet little sour

diluted cranberry

sweet and salty

bland sourish sweet

very

sour a bit bitter

more sweet than sour

bitter and v sour

sweet bit sourish

bitter sweet

sweet sour

grape(black)

Tangy,

Sweet, sharp

Sweet, tangy

Bitter, citrusy, strong

Bitter, sharp

Sweet, fruity

Very sweet, tangy/sharp

Sweet, citrusy

sweet, citrus

sweet, fruity, little sharp, sour

Apple

Tropical

Salty not sharp

sugary, sweet

sweet, subtle

sweet, sugary

sweet, sugary fruity

bitter sour

sharp, very sweet

sweet, sour sharp

sweet, sharp

sweet strong flavour

pieapple

Group B

Juice A Juice B Juice C Juice D Juice E Juice F Juice G
Student # Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only Blind + nose clip blind only

1 Taste

salty

sweet, sharp

Juice ID tomato tomato

cranberry juice apple juice pineapple grapefruit juice grapefruit juice

orange juice orange juice apple juice apple juice

2 Taste salty

sweet

bitter,dry dry, bitter

sweet sharp and sweet

sweet, citrus sweet, dry

Juice ID Tomato tomato cranberry juice cranberry juice apple juice pineapple grapefruit juice grapefruit juice

mango juice orange juice orange juice apple juice apple juice

3 Taste salty bitter and sour sour

sweet bitter bitter sour

sweet sweet and sour sweet and sour sweet and sour

Juice ID tomato tomato orange

grape grape orange orange pineapple orange pineapple orange juice apple juice pineapple

4 Taste bitter bitter sweet sweet and sour a bit sweet sweet sour bitter sweet and sour sweet sweet and sour sweet sweet sweet
Juice ID tomato tomato apple

grape orange grapefruit juice grapefruit juice pineapple

orange juice

apple juice grape juice

5 Taste sour sour

sweet and sour sour sweet bitter sour sweet and sour sweet sweet and sour sweet sweet sweet

Juice ID tomato tomato orange apple pineapple pineapple

and lemon

orange tropical orange juice orange juice apple juice tropical

6 Taste

sour sweet sweet and sour very sweet sweet sour sour sweet and sour sweet sweet sweet and sour sweet sweet

Juice ID tomato tomato lemon lemon pineapple pineapple orange and lime orange tropical

orange juice orange juice apple juice apple juice

7 Taste

, soup like

Sour

, fruity

Pineapple

Sweet, tangy sweet Citrus sweet, tangy Sweet

Juice ID tomato Tomato

Pineapple grapefruit juice grapefruit juice

Apple pineapple orange juice pineapple Pineapple

8 Taste Savoury

Sour Sweet Sweet Sour, bitter

Tangy,

Sour, sweet

Juice ID Tomato Tomato

Blackcurrant/ cranberry apple juice Pineapple grapefruit juice grapefruit juice

Apple Blackcurrant orange juice

Blackcurrant

Taste salty

sweet and sour salty sweet

,citrus

,bitter

sweet sweet

Juice ID tomato tomato tropical apple

pineapple grapefruit juice grapefruit juice

tropical pineapple orange juice grapes apple juice

10 Taste

sweet

sweet,sour

Juice ID tomato tomato pineapple cranberry juice tropical tropical grapefruit juice grapefruit juice

pineapple orange juice orange juice grapes apple juice

11 Taste

sweet and sour sweet,sour

very bitter sour,bitter

sweet,sour Sour, sweet

Juice ID tomato tomato apple cranberry juice

orange lemon grapefruit juice pineapple juice pineapple pineapple orange juice pineapple apple juice

12 Taste

sour, bitter sour sweet and sour sweet and sour

very bitter

sour very sour bitter,sour bitter

sour

Juice ID tomato tomato cranberry juice cranberry juice pineapple pineapple grapefruit juice grapefruit juice apple mango juice orange juice orange juice apple juice apple juice
13 Taste bitter

bitter sweet sweet

acidic

acidic bitter acidic bitter acidic

Juice ID

tomato berry

peach pineapple apple lime clementine apple lemon orange juice orange grape juice

14 Taste bitter acidic bitter bitter sour

sweet sour sour bitter sour acidic bitter sour sweet

acidic bitter

sweet sour

Juice ID kiwi tomato berry

tomato pineapple apple grapefruit juice Lemon peach clementine orange juice peach apple juice

salty, dry

bry, bitter

dry, astringent

very sweet and abit dry

sweet bit dry

sour, bitter

dry, bitter

sharp fruity

sharp, citrus like

sweeter, bit sharp

sweet, dry

dry sweet

cranberry juice

pineapple juice

mango juice

soupy, salty

bitter,dry

dry,sweet,bitter

sharp and sweet

citrus,sharp

more bitter and sharp

pineapple/lemon

little sour and bitter

a bit sweet

sweet and sour

rasberry

orange and apple juice

mix fruit

pinapple

sweet and tangy

lime

orange and lime

bitter and tangy

grapejuice

Bitter, tangy

Savoury

Chemicals

Citrus

Bitter, astringent

Bitter, sour

tangy,sour

Blackcurrant

Blackcurrant/ cranberry

Orange juice

blackcurrant

Savoury, salty

Sweet, sour

Tangy, biter

Sour, tangy

Sour, astringent

Sour, citrus

Tangy, sour

Cheery

Lemon

Blackcurant

salty,bitter

sweet,mixed

sour,bitter

bitter,sour

acidic,sweet

sour, a bit sweet

sweet,sour

citrus, sweet

veggie juice

white

grapes

salty,earthy

saltty, earthy

sour,citric

astringent,citrus,tangy

sour,sweet,acidic.citrusy

citrus,sharp,bitter

bitter,sharp,astringent

sweet, sour, acidic

sharp, sour, acidic

citrus, sharp,sweet

citrus, swet ,sour

sweet,sharp

sour cherry

salty, tasless

bland, bitter

sweat

sour, citrucy.sweet

bitter,astringent

sweet,bitter,sour

bitter,sweet, sour

bitter,sour,sweet

cant tell

sour, ummami

more sweet, sour

bitter,tangy,citrus

sour, sweet

bitter, acidic

bitter and acidic

very

bitter acidic

very bitter and acidic

acidic bitter

acidic sweet

kiwi

clementine

sour bitter

bitter acidic sweet

sweet acidic

pear

Group A, and B

umami dry but sweet

thick, sweet

bitter acidic bitter, sour tangy, sweet

tangy sweet citric not sweet, sour sweet, thick sweet, astringic
Juice ID tomato tomato cranberry and rasp cranberry and rasp pineapple tropical grapefruit grapefruit apple pineapple orange apple tropical tropical
2 Taste umami, bitter and sweet umami, thick

astringic,sweet sweet, fruity Thick, sweet, fruit bitter, tangy bitter, sour bitter, fruity sweet sweet, tangy not too sweet thick and sweet sweet and watery
Juice ID tomato tomato cranberry grape pineapple pineapple grapefruit grapefruit tropical tropical orange orange grape apple
3 Taste sour,rich in textur sharp taste,very concentrated,alty sour,tangy mount sour

little sour

very sour and bitter sour sour,little sweet little bit sour mount sour bitter little sweet
Juice ID tomato tomato pineaple cranberry apple grapefruit orange juice concentrated orange juice forest fruit apple lemon/lemonade orange juice grape forest fruit
4 Taste

mostly sour, little bit sweet sweet sweet bitter, sour

very sweet very sweet sour little bit sweet little bit sour sour and sweet

Juice ID Tomato Tomato apple apple juice pineapple pineapple grapefruit juice grape fruit juice grape juice apple juice orange juice orange forest fruit cranberry

5 Taste salty/meaty/earthy salty/earthy sweet very tangy sweet sweet bitter bitter, sour sweet/tangy tangy/appley sour sour sweet sweet
Juice ID tomato tomato grape cranberry pineapple pineapple grapefruit grapefruit blackcurrent apple orange orange apple grape
6 Taste salty/heavy flavour salty/sour sour/tangy sour/bitter sweet/tangy sweet sour/bitter bitter/sour/tart sweet/sour sweet sweet/sourkick sour/tangy sweet/tangy sweet/tangy
Juice ID tomato tomato cranberry cranberry tropical tropical grapefruit grapefruit apple tropical orange orange grapefruit apple
7 Taste Salty,earthy,slightly sweet salty a little sweet tangy/sour sour,slightly sweet, astringic tangy, sweet tangy,sweet very bitter, sour bitter, sour after taste Sour, sweet Sour, sweet very sweet slightly sour Sour/tangy very sweet very sweet a little sour
Juice ID Tomato Tomato cranberry Cranberry Pineapple Pineapple Grapefruit Grapefruit lemon orange and lemon Orange Orange apple apple
8 Taste Very salty

Sour bitter after taste Sweet, tangy very sweet very bitter, sour very sour and bitter Sweet, Sour Sweet more sour than sweet Sour/tangy Sweet, sugary and bitter Sweet
Juice ID Tomato Tomato Cranberry Plum Pineapple pineapple Grapefruit grapefruit Orange Orange lemon/lemonade lemon apple apple
Taste thick, intense, not sweet SALTY, thick LITTLE BIT SWEET, bit thick

little bit sour, more sweet sweet, thick bitter very bitter, soft little sour, strong taste sour, soft sweet, soft sofe, sweet sweet, smooth sweet, sour, soft
Juice ID tomato tomato orange apple juice grape pineapple grapefruit grapefruit

cranbery pineapple orange apple grape
10 Taste concentrated, little thick, little sour thick, concentrated, sour little sweet, smooth sweet, smooth , sweet, smooth very sweet, soft bitter, smooth very bitter, smooth thick, sweet sweet, soft sweet, soft sweet, soft, little sour smooth, sweet soft, sweet
Juice ID tomato tomato orange grape pineapple pineapple grapefruit grapefruit mango apple orange juice orange apple apple
11 Taste salty+sour salty astringant, dry, sweet astringant bit sweet+bit acidic sweet bitter bitter acidic sweet+bit acidic bit sweet+bit acidic bit sweet bit sweet bit sweet
Juice ID tomato tomato grapefruit apple juice strawberry cramberry cramberry orange juice pineapple grape apple orange tropical apple
12 Taste salty salty bitter+bit sweet

sweet sweet bitter+salty bit acidic+bitter sweet+bit bitter bit bitter+sweet bit sweet bit sweet+bitter sweet+bit bitter sweet
Juice ID tomato tomato cramberry cramberry peach pineapple grapefruit grapefruit mango orange mixed fruits mixed fruits orange apple
13 Taste sour-sweet bitter peperry salty bell pepper and sweet bland sweet light most sweet sweet tropical sour very sour and bitter mild sour sour and sweet mix sour but more sweet sourish sweet sweet a bit sour sweet little sour
Juice ID tomato tomato diluted cranberry cranberry pineapple pineapple grapefruit grapefruit orange tropical orange orange apple apple
14 Taste sweet and salty sourish sweet bland sourish sweet

more sweet than sour very sweet sour a bit bitter bitter and v sour sweet bit sourish sour sweet a bit sour sweet a bit sour bitter sweet sweet sour
Juice ID tomato tomato cranberry cranberry grape(black) pineapple grape grape strawberry apple apple orange cranberry grape
15 Taste Salty very salty Sweet

Sweet, sharp Sweet, tangy Bitter, citrusy, strong Bitter, sharp Sweet, fruity Very sweet, tangy/sharp Sweet, citrusy

sweet, fruity sweet, fruity, little sharp, sour
Juice ID Tomato Tomato Cranberry Cranberry Apple Pineapple Grapefruit Grapefruit Tropical tropical orange orange mango apple
16 Taste Salty not sharp salty sugary, sweet sweet, subtle sweet, sugary sweet, sugary fruity bitter, sour bitter sour sharp, very sweet sweet, sour sharp sweet, subtle

sharp, very sweet sweet strong flavour
Juice ID Tomato tomato apple grape apple pieapple grapefruit grapefruit pineapple mango blackcurrent orange pineapple apple

Taste salty, dry salty bry, bitter dry, astringent very sweet and abit dry sweet bit dry sour, bitter dry, bitter sweet, sharp sharp fruity sharp, citrus like sweeter, bit sharp sweet, dry dry sweet

Juice ID tomato tomato cranberry juice cranberry juice apple juice pineapple grapefruit juice grapefruit juice pineapple juice mango juice orange juice orange juice apple juice apple juice

Taste salty soupy, salty bitter,dry dry,sweet,bitter sweet sharp and sweet bitter,dry dry, bitter citrus,sharp sweet sharp and sweet more bitter and sharp sweet, citrus sweet, dry

Juice ID Tomato tomato cranberry juice cranberry juice apple juice pineapple grapefruit juice grapefruit juice pineapple/lemon mango juice orange juice orange juice apple juice apple juice

Taste salty bitter and sour sour little sour and bitter a bit sweet sweet bitter bitter sour sweet and sour sweet sweet and sour sweet and sour sweet and sour

Juice ID tomato tomato orange rasberry grape grape orange orange pineapple orange pineapple orange juice apple juice pineapple

Taste bitter bitter sweet sweet and sour a bit sweet sweet sour bitter sweet and sour sweet sweet and sour sweet sweet sweet

Juice ID tomato tomato apple orange and apple juice grape orange grapefruit juice grapefruit juice pineapple mix fruit orange juice pinapple apple juice grape juice

Taste sour sour sweet and tangy sweet and sour sour sweet bitter sour sweet and sour sweet sweet and sour sweet sweet sweet

Juice ID tomato tomato orange apple pineapple pineapple

orange and lime orange tropical orange juice orange juice apple juice tropical

Taste bitter and tangy sour sweet sweet and sour very sweet sweet sour sour sweet and sour sweet sweet sweet and sour sweet sweet

Juice ID tomato tomato lemon lemon pineapple pineapple orange and lime orange tropical grapejuice orange juice orange juice apple juice apple juice

Taste Bitter, tangy

Sour Chemicals

Pineapple Bitter, astringent Bitter, sour tangy,sour Sweet, tangy sweet Citrus sweet, tangy Sweet

Juice ID tomato Tomato Blackcurrant Blackcurrant/ cranberry Orange juice Pineapple grapefruit juice grapefruit juice blackcurrant Apple pineapple orange juice pineapple Pineapple

Taste Savoury Savoury, salty Sweet, sour Sour Sweet Sweet Sour, bitter Tangy, biter Sour, tangy Sour, astringent Tangy, Sour, citrus Tangy, sour Sour, sweet

Juice ID Tomato Tomato Cheery Blackcurrant/ cranberry apple juice Pineapple grapefruit juice grapefruit juice Lemon Apple Blackcurrant orange juice Blackcurant Blackcurrant

Taste salty salty,bitter sweet,mixed sweet and sour salty sweet sour,bitter

acidic,sweet sour, a bit sweet

citrus, sweet sweet sweet

Juice ID tomato tomato tropical apple veggie juice pineapple grapefruit juice grapefruit juice

tropical pineapple orange juice grapes apple juice

Taste salty,earthy saltty, earthy sour,citric astringent,citrus,tangy sour,sweet,acidic.citrusy sweet citrus,sharp,bitter bitter,sharp,astringent sweet, sour, acidic sharp, sour, acidic citrus, sharp,sweet citrus, swet ,sour sweet,sour sweet,sharp

Juice ID tomato tomato pineapple cranberry juice tropical tropical grapefruit juice grapefruit juice sour cherry pineapple orange juice orange juice grapes apple juice

Taste salty, tasless bland, bitter sweat sweet and sour sweet,sour sour, citrucy.sweet bitter,astringent very bitter sour,bitter sweet,bitter,sour bitter,sweet, sour bitter,sour,sweet sweet,sour Sour, sweet

Juice ID tomato tomato apple cranberry juice cant tell orange lemon grapefruit juice pineapple juice pineapple pineapple orange juice pineapple apple juice

Taste sour, ummami sour, bitter sour sweet and sour sweet and sour more sweet, sour very bitter bitter,tangy,citrus sour very sour bitter,sour bitter sour, sweet sour

Juice ID tomato tomato cranberry juice cranberry juice pineapple pineapple grapefruit juice grapefruit juice apple mango juice orange juice orange juice apple juice apple juice

Taste bitter bitter, acidic bitter sweet sweet bitter and acidic

very bitter and acidic acidic acidic bitter acidic bitter acidic bitter acidic acidic sweet

Juice ID kiwi tomato berry clementine peach pineapple apple lime clementine apple lemon orange juice orange grape juice

Taste bitter acidic bitter bitter sour sour bitter sweet sour sour bitter sour acidic bitter sour sweet bitter acidic sweet acidic bitter sweet acidic sweet sour

Juice ID kiwi tomato berry pear tomato pineapple apple grapefruit juice Lemon peach clementine orange juice peach apple juice

umami and sweet	astringic,bitter,sweet	really sweet, sour	very sweet, fruity	astringant, dry, sweetish	mount sour,little sweet	very sour very bitter	Salty,rich in texture	little bit sweet and salty	Sour, not sweet	fairy bitter and sour
very salty, sour	Sour, bitter a bit tart	soft ,sour sweet	cranbery juice	a bit sweet+bitter	very sour a bit bitter	Tangy, little sweet	sweet, citrusy, little tangy	sweet, sharp, fruity
17
18
19
20
21
lime and lemon
22
23	Savoury, soup like	Citrus, fruity
24
25	bitter,sour,citrus	sweet,sour,bitter
white grapes
26
27
28
29	very bitter acidic
30

Data analysis

Purpose:This assignment assesses your ability to correctly analyse data, interpret what it means and relate it to your taught work.

Background:
You have been given 2 research papers on separate but related topics. The following data has been extracted from these papers. Please look at the data and answer the questions relating to it, including in your answer information you have gained from reading the papers thoroughly. You will not get good marks simply from looking at the extracts – you need to read the papers themselves.

1. Mean systolic blood pressure differences between babies who were breastfed and those who were bottle fed (Martin et al, 2005; Figure 2).

Figure 2: Mean diastolic blood pressure differences between babies who were breastfed and those who were bottle fed (Martin et al, 2005; Figure 3).

Q1. Using the figures above and your reading of the paper, what are the main messages of the figures? Explain your answer. You must make reference in your answer to the effects of infant feeding upon systolic & diastolic blood pressures, commenting on effects of study size and duration of breastfeeding

Q2. What factors did the authors identify as potential explanations for the marked heterogeneity observed in studies on blood pressure and infant feeding, and why?

Q3. Why is raised blood pressure a public health concern, and how may breastfeeding affect risk?

Part 2: Duration of breastfeeding & risk of overweight
(Table 1, McCrory & Layte, 2012).
Use the table below to answer the following questions.

Q4.
What is meant by an ‘odds ratio’ for overweight and obesity? Explain in the context of the table above.

Q5.
What explanation(s) did the authors offer for their findings?

References

Martin RN, Gunnell D & Davey Smith G (2005) Breastfeeding in Infancy and Blood Pressure in Later Life: Systematic Review and Meta-Analysis. Am J Epidemiol 161(1): 15-26.

McCrory C & Layte R (2012) Breastfeeding and risk of overweight and obesity at nine-years of age. Social Science & Medicine 75: 323-330.

Useful information

Sedgwick P (2012) How to read a forest plot. BMJ 345:e8335

Sedgwick P (2012) Absolute and relative risks. BMJ 345:e5613

Sedgwick P (2012) Absolute and relative risks correction. BMJ 345:e6252

Sedgwick P (2012) Meta-analysis: tests of heterogeneity. BMJ 344:e3972

University of Nottingham (2007) RLO: Presenting and interpreting meta-analyses. Web access at

http://www.nottingham.ac.uk/nmp/sonet/rlos/ebp/meta-analysis2/index.html

World Cancer Research Fund/American Institute for Cancer Research (2007) In: Food, nutrition, physical activity and the prevention of cancer: a global perspective. Second expert report. WCRF/AICR: Washington. Chapter 3: Judging the evidence p48-62.

ECE 415 Control Systems, Fall 2018
Final Project
4-Dec-2015
Due: Saturday, 15-Dec-2018 by 11:55 pm via Isidore

Instructions:

1. You may not use any reference source other than your own class notes, your own
homework and the homework solutions I have provided. You may not refer to any other
textbook, other course notes, or other published material, including the web.

2. You may not consult another human being. This is your work, and yours alone.

3. There are four questions, out of which you need to choose three. Submit your
solutions to three problems only, for a total of 75 points.

4. Work neatly and be precise, concise and to the point. Because this is a formal project, I
will not struggle to grade a poorly organized or messy solution, and will automatically
assign a grade of zero to any problem I cannot easily read.

5. All the problems are design problems, and they require you to use MATLAB to solve them.
Provide all your MATLAB code, uncompressed, via Isidore, as .m or .slx files.

6. Write a report on the results using the following outline (the page limits are strict):
• Title page (with your name and the date and an Executive Summary (abstract) which

is a short paragraph description of what the report is about).
• Design Problem Descriptions (for the three problems): ≤ 2 pages.
• Controller Design Approach: ≤ 3 pages

o Describe your approach to designing the compensators.
o Provide the final compensators that you designed (the ones that meet the

specifications).
• Verification of Specifications: ≤ 3 pages

o Provide simulations / analysis to verify that you meet the specifications.
You may organize these elements problem by problem, or one by one. It is your choice.

7. Make sure your all your final control designs are clearly marked, and in the form

”

It is essential that you provide clear evidence of having followed a design procedure.
Failing to do so will cause you to lose points.

8. Turn in your report in PDF format via Isidore. It should be at most 9 pages long.

9. Only turn in your report if the paragraph below applies to you.

I certify that I have worked on this test exclusively on my own, and that all the work
I am turning in is completely my own. I have not given any help, received any help,
nor witnessed anyone else giving or receiving help to solve this test. I understand
that cheating on this test will automatically result in a failing grade for the test and
for the class.

C (s ) = K
s + z
s + p

Owner
铅笔

For all problems below we will use the standard negative unity feedback system shown here:

1. (25 pts) The plant is given by ” . Design a controller that achieves

” and a settling time (2% criterion) ” . In addition, the steady-state
requirement for tracking a ramp is ” . Your controller should be of first order (it can be
either a lead or a lag controller).

2. (25 pts) The plant is given by ” . Using the design approach of

your choice, design a controller that yields a percent overshoot to a step input ” ,
and ” for a ramp input. Hint: consider first designing a lead compensator, and then a
lag compensator, to arrive at a lead-lag design.

3. (25 pts) The plant is given by ” . Using frequency domain methods, design

a controller that achieves a steady-state error less than 10% for a step input, a phase
margin ” and a settling time (2% criterion) ” for a step input. Your controller
should be of first order (it can be either a lead or a lag controller).

4. (25 pts) Using the approach of your choice, design a lead or lag controller for the purpose
of dc motor position control. The transfer function modeling the motor, from input voltage
” to shaft angle ” , is given by ” . We assume to be able

to accurately measure the angle, and your controller should produce a voltage signal to be
output to the motor. The reference signal to track is a train of steps with amplitude 1 (that
is, alternating between -1 and 1) and frequency equal to 0.5 Hz. You are given the task of
achieving a peak time ” , and a maximum percent overshoot to a step input
” .

Be sure to show a plot of your design tracking a train of steps (not a single step
response!) with the characteristics specified. Show three complete periods in your plot.

P (s ) =
4

s (s + 1)(s + 4)
PM ≥ 50∘ Ts ≤ 4s

Kv ≥ 2

P (s ) =
81

s ( 14895 s2 + 169 s + 1)
P . O . ≤ 10 %

Kv ≥ 20

P (s ) =
0.5(s + 9.8)
s2 + 2s + 21

PM ≥ 45∘ Ts ≤ 5s

V (s ) θ (s ) P (s ) =
θ (s )
V (s )

=
1

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Tp ≤ 0.05s
P . O . ≤ 4.6 %

−
C(s) P(s)

R(s) Y (s)

American Journal of Epidemiology
Copyright © 2005 by the Johns Hopkins Bloomberg School of Public Health
All rights reserved

Vol. 161, No. 1
Printed in U.S.A.

DOI: 10.1093/aje/kwh338

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PRACTICE OF EPIDEMIOLOGYMETA-ANALYSIS

Breastfeeding in Infancy and Blood Pressure in Later Life: Systematic Review and
Meta-Analysis

Richard M. Martin, David Gunnell, and George Davey Smith

From the Department of Social Medicine, University of Bristol, Bristol, United Kingdom.

Received for publication January 29, 2004; accepted for publication June 25, 2004.

The influence of breastfeeding on blood pressure in later life is uncertain. The authors conducted a systematic
review of published studies from which estimates of a mean difference (standard error) in blood pressure between
breastfed and bottle-fed subjects could be derived. They searched MEDLINE and Excerpta Medica (EMBASE)
bibliographic databases, which was supplemented by manual searches of reference lists. Fifteen studies (17
observations) including 17,503 subjects were summarized. Systolic blood pressure was lower in breastfed
compared with bottle-fed infants (pooled difference: –1.4 mmHg, 95% confidence interval (CI): –2.2, –0.6), but
evidence of heterogeneity between study estimates was evident (χ216 = 42.0, p < 0.001). A lesser effect of breastfeeding on systolic blood pressure was observed in larger (n ≥ 1,000) studies (–0.6 mmHg, 95% CI: –1.2, 0.02) compared with smaller (n < 1,000) studies (–2.3 mmHg, 95% CI: –3.7, –0.9) (p for difference in pooled estimates = 0.02). A small reduction in diastolic blood pressure was associated with breastfeeding (pooled difference: –0.5 mmHg, 95% CI: –0.9, –0.04), which was independent of study size. If causal, the small reduction in blood pressure associated with breastfeeding could confer important benefits on cardiovascular health at a population level. Understanding the mechanism underlying this association may provide insights into pathways linking early life exposures with health in adulthood.

blood pressure; bottle feeding; breast feeding; cardiovascular system; hypertension; infant nutrition; milk,
human; review literature

Abbreviation: CI, confidence interval.

Evidence is growing that blood pressure levels in both
childhood and young adulthood are influenced by factors
operating early in life (1–4) and are associated with later
cardiovascular disease (5). Specifically, several cohort
studies suggest that blood pressure may be determined by
early nutritional exposures, including sodium intake in
infancy (6), consumption of formula feed (7), and breast-
feeding (8). Detection, treatment, and control of hyperten-
sion in adulthood does not reduce cardiovascular disease risk
to normotensive levels (9), supporting efforts to identify
primary prevention interventions that could be started in
early life. Any long-term effect of breastfeeding on blood
pressure levels may have implications for policies promoting
breastfeeding, particularly among the least affluent families

with the lowest breastfeeding rates (10) and the highest risks
of premature cardiovascular disease (11), and it may
increase understanding of cardiovascular disease mecha-
nisms operating through early life exposures.

Interpreting individual studies of the association between
breastfeeding and blood pressure in isolation is complicated.
Firstly, cohort studies include infants born in different
decades during the 20th century (8, 12, 13). The composition
of bottle (artificial) feeds has changed during this time, and
associations with particular components of these feeds may
explain differences in results. Secondly, different definitions
of breastfeeding have been used (13, 14). Thirdly, the
strength of the relation may depend on the age at outcome
measurement (15, 16). Finally, control for confounding

Correspondence to Dr. Richard M. Martin, Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Bristol,
United Kingdom, BS8 2PR (e-mail: richard.martin@bristol.ac.uk).

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factors may have been inadequate (17). We conducted a
systematic review and meta-analysis of studies reporting on
blood pressure levels in breast- and bottle-fed subjects and
explored possible sources of heterogeneity using meta-
regression (18).

MATERIALS AND METHODS

Included studies

Articles were included if they fulfilled the following
criteria: 1) having been breastfed in infancy was compared
with bottle (artificial) feeding, 2) systolic or diastolic blood
pressure had been measured as an outcome, and 3) an esti-
mate of the mean difference in blood pressure between
breast- and bottle-fed groups could be extracted from the
article. Our review was restricted to human subjects.

Data sources

We systematically searched all published papers, letters,
abstracts, and review articles on infant feeding and cardio-
vascular disease, cardiovascular disease risk factors, and
growth by using the MEDLINE and Excerpta Medica
(EMBASE) bibliographic databases from their inception to
April 2003. We used a combined text word and MESH
heading search strategy (refer to the Appendix), and we
manually searched reference lists of all studies that fulfilled
our eligibility criteria. Using the “saved searches” and “auto
alerts” automated facilities incorporated within the
MEDLINE and EMBASE databases, we reran the search
every week until May 2004. No restriction was made
regarding language of publication. Two papers then in press
but not yet published (19, 20) were also considered for inclu-
sion. When clarifications were required, we corresponded
with the authors, but no additional data were supplied. One
of the authors (R. M. M.) assessed study eligibility and
extracted data by using a prepiloted, standardized form.

We did not use a simple quality score, which might be
arbitrary. Instead, we conducted meta-regression analyses to
assess specific aspects of quality, including control of
confounding, loss to follow-up, recall bias, definition of
breastfeeding, and sample size (refer to the information
below).

Statistical analysis

A meta-analysis of the mean differences, and their stan-
dard errors, in systolic and diastolic blood pressures between
breastfed and bottle-fed infants was conducted. The fully
adjusted estimates from individual studies were used in the
meta-analysis where available; otherwise, the crude esti-
mates were used. Heterogeneity was assessed by using the Q
test (18). Because heterogeneity was marked, random-
effects models were computed. One paper followed up
subjects at ages 13–16 years (15), some of whom were
included in an analysis based on follow-up at ages 7.5–8
years (16). Because the two studies cannot be considered
independent in a meta-analysis, we performed a meta-
analysis with and without including this later follow-up

study to determine its impact on the overall pooled mean
difference.

Selected study characteristics, chosen a priori, were
entered as indicator variables in separate meta-regression
analyses (18) to assess their impact on between-study varia-
tion (heterogeneity), as follows: study size (<1,000/ ≥1,000); reliance on maternal recall of breastfeeding beyond infancy (yes/no); whether breastfeeding occurred for at least 2 months (yes/no); whether breastfeeding was exclusive for at least 2 months (yes/no); age at measurement of blood pres- sure (<10 years/11–45 years/>45 years); decade of birth
(before 1980/after 1980); proportion of target population
included in the main analysis (<30 percent/31–60 percent, >61 percent); method of blood pressure measurement (auto-
mated/manual); and whether effect estimates in the final
models controlled for social factors in childhood or adult-
hood (yes/no), maternal factors in pregnancy (yes/no), or
current weight (yes/no). Papers that assessed blood pressure
in infancy only (age <1 year) were investigated separately because the focus of our inquiry was on the long-term, rather than acute, effects of breastfeeding. Funnel plots, the Egger (weighted regression) test, and the Begg and Mazumdar (rank correlation) tests for funnel plot asymmetry were conducted to examine the relation between sample size and observed mean differences in blood pressure by infant feeding group (21).

Sensitivity analysis

We examined the likely impact on the overall pooled
relation between breastfeeding and blood pressure of also
including the five potentially eligible studies that did not
provide quantitative estimates (table 1). In all five studies,
null results were reported, and a mean difference in systolic
blood pressure of 0.0 mmHg between breast- and bottle-fed
subjects was assigned. The meta-analysis was then
repeated to estimate the pooled mean difference when all
studies were included (i.e., both those with published esti-
mates and the five studies without published estimates).
For the five studies without quantitative data, an estimate
of the standard error was based on the sample size and
assumed a standard deviation of 10 mmHg where this
parameter was not reported (22–24).

RESULTS

Description of studies

The electronic search yielded 3,403 references. Abstract
review suggested that 17 were potentially relevant to the
analysis relating breastfeeding with blood pressure beyond
12 months (8, 12–16, 23–33). Ten other papers were identi-
fied from a manual search of reference lists (22, 34–42). Of
the 27 studies, 12 published studies were included in the
meta-analysis (8, 12–16, 25–27, 34–36) (Web table 1; this
information is described in the supplementary table referred
to as “Web table 1” in the text, which is posted on the
Journal’s website (http://aje.oupjournals.org/)). Reasons for
exclusion (n = 15) are given in figure 1. Together with the
three additional studies identified after April 2003 (which

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involved 10,062 subjects) (19, 20, 43), 15 studies with
17,503 participants were included in the meta-analysis
relating breastfeeding with blood pressure beyond 12
months (Web table 1).

Two of these 15 studies were based on a follow-up of a
randomized controlled trial in preterm infants (15, 16), eight
were prospective cohorts (8, 14, 20, 25–27, 36, 43), and one
was a historical cohort (13); in four cross-sectional surveys
of blood pressure, infant feeding history was based on retro-
spective recall by the mother (12, 19, 34, 35). These studies
included populations from the United Kingdom, Finland,
Holland, Belgium, Italy, Czech Republic, Croatia, South
Africa, and Australia. Individual studies were relatively
homogeneous with respect to ethnicity. The year of birth of
the subjects ranged from 1918 to 1994. The proportion of the
target population included in the main analysis was unstated
in one paper (35), less than 30 percent in four studies (12, 13,
15, 36), 30–60 percent in four studies (8, 20, 27, 43), and
more than 60 percent in six studies (14, 16, 19, 25, 26, 34).

From these 15 studies, 17 estimates of systolic blood pres-
sure differences were derived, of which 12 included males
and females combined and five were sex specific. Eleven
systolic blood pressure observations (nine studies) were of
children (aged 1–16 years), and six observations (five
studies) occurred in later adulthood (age ≥17 years). One
study reported results for diastolic blood pressure only (25).
From the 15 studies, 13 estimates of diastolic blood pressure
differences were derived, 12 of which included males and
females combined and one of which was for males only.
Nine diastolic blood pressure observations (eight studies)
were of children aged 1–16 years, and four observations
(four studies) occurred in adulthood (age ≥17 years).

Definitions of breastfeeding

The 15 studies used different definitions of breastfeeding.
In a randomized controlled trial with follow-up at ages 7.5–
8 years (16) and ages 13–16 years (15), preterm infants were
randomly assigned to donated, banked breast milk or

TABLE 1. Studies reporting on associations between method of infant feeding and blood pressure beyond 12 months of age that
were not included in the current meta-analysis

* Includes partially breastfed.

First author, source
(year of publication)

(reference no.)

No. breastfed*;
no. bottle fed

(sex)

Infant feeding
comparison

Infant year of
birth

Age at which infant
feeding was assessed

Age at which
outcome

measurement
occurred

Description
of results

Baranowski, families
from an ethnically
diverse population in
Texas (1992) (22)

245 total (M† + F†) Duration of any
breastfeeding

Not stated Interviewer
administered
questions to mother
3–4 years after
infant’s birth

3–4 years No significant correlations
between duration of
breastfeeding and SBP†
or DBP† observed;
quantitative estimates not
reported

Cobaleda Rodrigo,
Madrid, Spain (1989)
(23)

1,893 total (M + F) Ever vs. never
breastfed

1965–1983 0–18 years; method
unclear

0–18 years No significant differences
between duration of
breastfeeding and SBP
or DBP observed; no
quantitative estimates
given

Simpson, births in
Dunedin maternity
hospital, New Zealand
(1981) (37)

692 total (M + F) Ever vs. never
breastfed

1972–1973 3 years; method
unclear

7 years No significant difference in
breastfeeding rates or
duration of breastfeeding
when comparing children
with high, medium, and
low blood pressure; no
quantitative estimates
given

Marmot, subsample of
238 eligible subjects
living in London and
Bristol, United
Kingdom who were
part of the 1946
national birth cohort
(n = 5,362), England
(1980) (24)

95; 47 (M + F) Exclusively breastfed
for 5 months vs.
exclusively bottle
fed

1946 First and third year of
life; methods not
stated

31–32 years “There were no consistent
differences [in blood
pressure levels] between
those who had been
breastfed and those who
had been bottle fed”; no
quantitative estimates
given

Fall, 297 women born
and still living in East
Hertfordshire (total
births = 5,585),
England (1995) (41)

279; 11 (F) Breastfed, bottle fed,
breast- and bottle
fed

1923–1930 During infancy; infant
feeding mode
recorded by health
visitors

60–71 years “No differences occurred
between the three
feeding groups in any of
the risk factors
measured” (included
systolic and diastolic
blood pressures); no
quantitative estimates
given

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preterm formula (either as the sole diet or a supplement to
mother’s milk) until they weighed 2,000 g or were
discharged to home. In the other studies, the exposure was
defined as 1) any breastfeeding in five studies (12, 19, 25,
26, 35); 2) exclusive breastfeeding in five studies (exclusive
for the first 10 days only (13), for at least 3 months (27, 34),
for at least 15 weeks (8), or for at least 12 months (36)); 3)
both any breastfeeding and exclusive breastfeeding for at
least 2 months in one study (43); and 4) any breastfeeding for
at least 3 months in one study (14) and at least 6 months in
another (20). In all studies except the randomized controlled
trial (15, 16), the comparator group was exclusive bottle
feeding. Five of the studies (providing six observations)
relied on maternal recall beyond infancy, ranging from 3–18
years (14), to 3 years (27), to 5–7 years (34), to 20–28 years
(12), and to 44–60 years (19).

Breastfeeding and systolic blood pressure

The results for systolic blood pressure, shown in figure 2,
are based on 14 studies with 17 observations. Mean systolic
blood pressure was lower in breastfed infants compared with
bottle-fed infants according to 10 observations from eight
studies (8, 14, 15, 20, 26, 35, 36, 43). Seven observations
(from six studies) showed no or little difference in systolic
blood pressure among breastfed versus formula-fed infants
(12, 13, 16, 19, 27, 34). Two of these seven observations
were from the randomized controlled trial in preterm infants
with follow-up at ages 7–8 years (16). When the original
study was followed up into adolescence (ages 13–16 years),
having received breast milk was associated with a 2.7-
mmHg reduction in blood pressure (15).

In a random-effects model, mean systolic blood pressure
was lower among breastfed infants (mean difference: –1.4

FIGURE 1. Summary of outcomes of studies retrieved for analysis, 1966–2004.

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mmHg, 95 percent confidence interval (CI): –2.2, –0.6; p =
0.001) (figure 2). There was also evidence of marked hetero-
geneity between studies (χ216 = 42.0, p < 0.001). Exclusion of the study by Singhal et al. (15) (because of lack of inde- pendence from Lucas et al.’s study (16)) had little impact on the pooled difference (–1.3, 95 percent CI: –2.2, –0.5). Controlling for study size in a meta-regression analysis lowered the τ2 estimate of between-study variation from 1.69 when study size was not included in the model to 0.47 when study size was included, suggesting that some of the

observed heterogeneity was explained by study size. In a
stratified meta-analysis, a smaller effect of breastfeeding on
later systolic blood pressure was observed in the larger
studies (n ≥ 1,000) (difference: –0.6 mmHg, 95 percent CI:
–1.2, 0.02; p = 0.06) compared with the smaller studies (n < 1,000) (difference: –2.3 mmHg, 95 percent CI: –3.7, –0.9; p = 0.001). This difference was unlikely to be due to chance (p = 0.02). There was evidence of heterogeneity in models restricted to small studies (χ212 = 27.1, p = 0.007) but less evidence among the four larger studies (χ23 = 6.1, p = 0.1).

FIGURE 2. Mean difference (95% confidence interval) in systolic blood pressure (mmHg) for infants who were breastfed minus infants who
were bottle fed: studies reporting on the association between breastfeeding and systolic blood pressure, 1966–2004. The first author, the year of
publication, and the reference number (in parentheses) are indicated on the y-axis. These studies are arranged in descending order of mean age
at which blood pressure was measured. The box corresponding to each study is proportional to the inverse of the variance, with horizontal lines
showing the 95% confidence intervals of the mean difference in systolic blood pressure (mmHg). The combined estimate is based on a random-
effects model shown by the dashed vertical line and diamond (95% confidence interval). The solid vertical line represents the null result, that is,
zero mean difference in blood pressure. Lucas 1 or 2 denotes estimates using different comparator groups (Web table 1). * Female-specific esti-
mates; ** male-specific estimates.

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In studies where the duration of breastfeeding was at least
2 months, the pooled blood pressure difference between
breast- and bottle-fed groups (–2.0 mmHg) was on average
1.6 mmHg larger (95 percent CI: –0.4, 3.5; p = 0.1) than in
studies with a shorter duration of breastfeeding (pooled
difference: –0.6 mmHg). Similarly, the difference in blood
pressure between breast- and bottle-fed groups was 1.4
mmHg greater (95 percent CI: –0.4, 3.2; p = 0.1) in those
born up to 1980 (pooled difference: –2.7 mmHg) compared
with those born after 1980 (pooled difference: –0.8 mmHg).

Only four of the 17 observations on systolic blood pressure
controlled for potential socioeconomic (19, 20, 43) or
maternal antenatal factors (such as body mass index,
smoking in pregnancy, education, parity, marital status) (8,
20, 43) or current body size (8, 20, 43). Controlling for
confounding produced a greater than 30 percent reduction in
crude effect estimates in two (19, 43) of three studies in
which comparison with crude estimates was possible. In
meta-regression analysis, there was weak evidence that
studies not controlling for socioeconomic factors (pooled
difference: –2.0 mmHg) had mean differences in blood pres-
sure 1.4 mmHg higher (95 percent CI: –0.6, 3.3; p = 0.17)
than in studies controlling for socioeconomic factors (pooled
difference: –0.9 mmHg). In one study, a large reduction in
blood pressure associated with having been breastfed for at
least 3 months (Web table 1) was reported to have been
somewhat attenuated after controlling for current weight,
age, birth weight, time of birth, birth order, mother’s age,
and history of high antenatal maternal blood pressure (14),
but quantitative estimates suitable for inclusion in the meta-
analyses were not available. Several studies controlled for
current weight (14) or body mass index (8, 15) or ponderal
index (20) in their final model, which may have had the
effect of overcontrolling for a factor on the causal pathway if
breastfeeding lowers blood pressure by reducing later
adiposity (44).

In meta-regression analyses, there was little evidence that
heterogeneity was explained by reliance on maternal recall
of breastfeeding (p = 0.9), age at measurement of blood pres-
sure (p = 0.8), whether breastfeeding was exclusive for at
least 2 months (p = 0.6), method of blood pressure measure-
ment (p = 0.2), or proportion of the target population
included in the main analysis (p = 0.9).

Breastfeeding and diastolic blood pressure

The results for 13 observations (12 studies) relating to
diastolic blood pressure are shown in figure 3. Mean dia-
stolic blood pressure was lower among breastfed infants
according to nine observations from eight studies (8, 12, 15,
16, 19, 20, 25, 43). In a random-effects model, the pooled
mean diastolic blood pressure was lower among breastfed
infants (difference: –0.5 mmHg, 95 percent CI: –0.9, –0.04;
p = 0.03). There was less evidence of heterogeneity between
estimates (χ212 = 20.2; p = 0.06) than in the analysis of
breastfeeding and systolic blood pressure. Exclusion of the
study by Singhal et al. (15) had little impact on the pooled
difference (–0.4, 95 percent CI: –0.8, –0.01). The effect of

breastfeeding on later diastolic blood pressure was similar in
the four larger studies (n ≥ 1,000) (difference: –0.4 mmHg,
95 percent CI: –0.9, 0.1; p = 0.10) compared with the seven
smaller studies (n < 1,000) (difference: –0.6 mmHg, 95 percent CI: –1.5, 0.2; p = 0.15). Studies that relied on maternal recall of breastfeeding beyond infancy showed pooled differences in mean diastolic blood pressure (0.0 mmHg) that were 0.6 mmHg smaller (95 percent CI: 0.2, 1.1; p = 0.004) than in studies that did not rely on recall (pooled difference: –0.7 mmHg).

We found little evidence that between-study heterogeneity
in estimates was explained by age at measurement of blood
pressure (p = 0.5), decade of birth (p = 0.2), stipulation of a
minimum duration of breastfeeding (p = 0.5), proportion of
the target population in the main analysis (p = 0.2), whether
breastfeeding was exclusive for at least 2 months (p = 0.2),
method of blood pressure measurement (p = 0.4), or whether
effect estimates controlled for socioeconomic factors (p =
0.9), maternal factors in pregnancy (p = 0.9), or current
weight (p = 0.9).

Studies that formally tested for interaction found little
evidence of sex differences in the association between
breastfeeding and systolic or diastolic blood pressure (20,
43). Repeating analyses after excluding the first published
(in 1981) of the included studies (35, 36), which could be
regarded as hypothesis-generating reports, made little differ-
ence to the pooled-effect estimates for systolic (mean differ-
ence: –1.1 mmHg, 95 percent CI: –1.8, –0.4; p = 0.003) or
diastolic (mean difference: –0.5 mmHg, 95 percent CI: –1.0,
–0.06; p = 0.03) blood pressure.

Small study effects

For systolic blood pressure, there was evidence of differ-
ential small study effects on inspection of funnel plots
(figure 4) and the Begg (p = 0.09) test for funnel plot asym-
metry, but there was no such evidence for diastolic blood
pressure (Begg test: p = 0.3). That is, we found some
evidence that small studies (i.e., those with higher standard
errors, located to the right of the figure), compared with
larger studies, reported larger mean differences in systolic
blood pressure between infant feeding groups.

Excluded studies

Table 1 summarizes the results from the five studies not
included in the meta-analysis because a mean difference in
blood pressure could not be obtained (22–24, 37, 41). All
reported no “statistically significant” association between
breastfeeding and either systolic or diastolic blood pressure.
These studies were relatively small—only 3,262 subjects in
total compared with 17,503 included in the meta-analysis. In
a sensitivity analysis, inclusion in the meta-analysis of the
assumed zero estimates from the five studies (table 1) with
no published mean differences attenuated the overall
summary estimate for systolic blood pressure (mean differ-
ence: –1.0 mmHg, 95 percent CI: –1.6; –0.4; p = 0.002), but
there was still strong evidence of an inverse association.

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Blood pressure in infancy

Overall, six studies were identified that examined the rela-
tion between infant feeding mode and blood pressure
measured before 12 months of age (32, 39, 40, 45–47) (table
2). The mean difference in blood pressure by feeding mode,
and the associated standard error, could be estimated from
four of these studies (six observations) (32, 40, 45, 46). In
random-effects models, the pooled systolic blood pressure
difference in infancy associated with breastfeeding was –1.7

mmHg (95 percent CI: –4.0, 0.6; p = 0.15), although there
was some evidence of heterogeneity (χ25 = 11.8; p = 0.04).
The pooled diastolic blood pressure difference in infancy
associated with breastfeeding was –1.1 (95 percent CI: –4.0,
1.8; p = 0.4; χ23= 8.2, p = 0.04).

DISCUSSION

Breastfeeding was associated with a 1.4- and 0.5-mmHg
reduction in systolic and diastolic blood pressure, respec-

FIGURE 3. Mean difference (95% confidence interval) in diastolic blood pressure (mmHg) for infants who were breastfed minus infants who
were bottle fed: studies reporting on the association between breastfeeding and diastolic blood pressure, 1966–2004. The first author, the year
of publication, and the reference number (in parentheses) are indicated on the y-axis. These studies are arranged in descending order of mean
age at which blood pressure was measured. The box corresponding to each study is proportional to the inverse of the variance, with horizontal
lines showing the 95% confidence intervals of the mean difference in diastolic blood pressure (mmHg). The combined estimate is based on a
random-effects model shown by the dashed vertical line and diamond (95% confidence interval). The solid vertical line represents the null result,
that is, zero mean difference in blood pressure. Lucas 1 or 2 denotes estimates using different comparator groups (Web table 1). * Male-specific
estimate.

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tively, although differences in systolic blood pressure
between feeding groups were reduced in large (difference:
–0.6 mmHg) compared with smaller (difference: –2.3 mmHg)
studies. These pooled estimates are similar to those found by
Owen et al. (48) in a recent review, even though the current
report includes recently published data on an extra 10,062
subjects from three studies that included more than 1,500
participants each.

Chance, bias, and confounding

A number of studies reported inverse associations between
breastfeeding and blood pressure, including two (of three)
with more than 3,500 subjects each (20, 43), suggesting that
these findings are unlikely to be due to type 1 error alone.
Selection bias would arise if excluded subjects had a
different breastfeeding–blood pressure association
compared with those who were included. In one study, a
protective effect of breast milk on blood pressure was
observed when 26 percent of the original cohort were
followed up at ages 13–16 years (15), but not when 81
percent were examined at ages 7.5–8 years (16), suggesting
either the possibility of selection bias in the later follow-up
or an amplification of the breastfeeding–blood pressure

association (49). When all the studies were considered, we
found similar effect estimates in studies with more than 60
percent follow-up and in those with less than 30 percent
follow-up, suggesting that the association between breast-
feeding and blood pressure did not systematically vary
between studies according to follow-up rates.

Although reporting of ever having been breastfed after up
to 20 years is highly correlated with obstetric records (50),
breastfeeding duration may be remembered less accurately
(51). Three cross-sectional studies relied on retrospective
reporting of exclusive (34) or any breastfeeding 7 years (34),
28 years (12), and 60 years (19) after birth, and these studies
showed little evidence of an association between breast-
feeding and blood pressure. In meta-regression analysis, reli-
ance on maternal recall was associated with an attenuation of
the difference in diastolic (but not systolic) blood pressure
between breast- and bottle-fed groups. Publication bias is a
concern because most studies in this review were small, and
mean blood pressure differences were greater in the smaller
compared with the larger studies.

Relatively few studies controlled for potential
confounding factors, although adjusted effect estimates were
attenuated by at least 30 percent in two studies (19, 43). In
the meta-regression analyses, studies controlling for socio-

FIGURE 4. Begg’s funnel plot (with pseudo 95% confidence limits) for studies reporting on the association between breastfeeding and systolic
blood pressure, 1966–2004.

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economic factors showed smaller systolic blood pressure
differences between breast- and bottle-fed subjects. The
distribution of breastfeeding was less socially determined
before World War II (52) compared with now (10), and
results from prewar cohorts may be free from confounding
by social class (53). The two prewar studies reviewed
showed little evidence of any association between breast-
feeding and blood pressure (13, 19), although nondifferential
misclassification is a possibility in the Caerphilly cohort that
relied on recall of breastfeeding status 44–60 years after
infancy (19), and the Dutch famine cohort may not be gener-
alizable (13). Accelerated postnatal weight gain is a potential
confounding factor because it is associated with raised blood

pressure (54) and may influence infant feeding practices
(55). In the only study to examine this issue (43), the associ-
ation of breastfeeding with blood pressure was not altered by
postnatal growth.

Relevance to contemporary cohorts

Modern formula feeds, which more closely resemble the
nutrient content of breast milk, were not developed until the
mid-1970s (56). Previously, bottle-fed infants were given
unmodified cow’s milk preparations and other alternatives
such as condensed milk (52, 57). Several studies of infants
born since 1980, however, show a blood-pressure-lowering

TABLE 2. Studies relating breastfeeding to blood pressure levels in infancy (before 12 months of age), by year of publication

* M, male; F, female; SBP, systolic blood pressure; DBP, diastolic blood pressure.

First author, source
(year of publication)
(reference no.)

No. breastfed;
no. bottle fed (sex)

Infant feeding
comparison

Infant year
of birth

Age at which
infant

feeding was
assessed

Age at which
outcome
measurement
occurred

Mean difference (breast-bottle) in
mmHg (standard error) Covariates in

multiply-adjusted
modelsUnadjusted or

simple model

Fully
adjusted
model

Studies included in the meta-analysis

Pomeranz, infants born
in a single hospital,
Israel (2002) (45)

7; 31 (M* + F*) Ever breastfed vs.
milk formula
made with
either mineral
water (low
sodium) or tap
water (high
sodium)

Not stated Birth 6 months SBP*: –6.1 (2.0);
DBP*: –7.3 (3.1)

Not given None

Bernstein, term infants
born in
Johannesburg
Hospital, South
Africa (1990) (46)

43; 81 (M + F) Exclusively
breastfed (n =
43) vs. low-
sodium formula
(n = 42) or
high-sodium
formula (n = 39)

1988 6 weeks 6 weeks Breastfed vs. low-
sodium formula:
–1.6 (2.2);
breastfed vs.
high-sodium
formula: –4.1
(2.0)

Not given None

Zinner, about 4% of
infants born in
hospitals in Boston,
Massachusetts, and
Rhode Island (1980)
(32)

154; 264 (M + F) Breastfed vs.
bottle fed

Not stated Infancy 1–6 days SBP: 0.0 (0.95);
DBP: –0.7 (0.92)

Not given None

Schachter, hospital
births, Pittsburgh,
Pennsylvania (1979)
(40)

30; 141 (M + F) Breastfed vs.
bottle fed

Not stated Infancy 6 months White ethnicity:
SBP: –0.5 (1.8);
DBP: –1.5 (1.3).
Black ethnicity:
SBP: 3.3 (3.3);
DBP: 5.8 (3.5)

Not given Results
stratified by
ethnicity

Studies excluded from the meta-analysis

Cohen, neonates born
at two hospitals,
United States (1992)
(47)

7; 11 (M + F)

Breastfed, bottle
fed

Not stated Infancy 24–94
hours
(mean:
55
hours)

During a feed; blood
pressure of
breastfed babies
approximately 15
mmHg higher
than those bottle
fed but about 2
mmHg higher
(derived from
figure 2) before
and 30–60
minutes after a
feed

de Swiet, 500 infants
born in a hospital in
Kent, England
(1977) (39)

Not stated
(M + F)

Breastfed, bottle
fed

1975 Infancy 4 days and
6 weeks

No differences in
blood pressure
levels between
infants breastfed
vs. bottle fed

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effect of breastfeeding (8, 15, 20, 25, 26, 43), suggesting that
if the results are causal, they are relevant to modern cohorts.

Population health implications

Reductions in population mean blood pressure levels of as
little as 2 mmHg could reduce the prevalence of hyperten-
sion by up to 17 percent, the number of coronary heart
disease events by 6 percent, and strokes and transient
ischemic attacks by 15 percent (9, 58). This reduction
equates to preventing 3,000 coronary heart disease events
and 2,000 strokes annually among those under age 75 years
in the United Kingdom (59). The effect estimates from our
meta-analysis could therefore translate into the prevention of
a substantial number of deaths annually.

Mechanisms

Breastfeeding could influence blood pressure via a variety
of mechanisms, including 1) reducing sodium intake in
infancy (60); 2) increasing intake of long-chain polyunsatu-
rated fatty acids, important structural components of tissue
membrane systems, including the vascular endothelium
(25); and 3) protecting against hyperinsulinemia in infancy
(61–63) and insulin resistance in early life (64), adolescence
(65), and adulthood (13), processes that may in turn raise
blood pressure via a number of mechanisms (66).

The concomitant association of breastfeeding with both
taller stature (particularly leg length) (67, 68) and lower
blood pressure is in line with previously reported inverse
relations between stature (particularly leg length) and blood
pressure in adulthood (64, 69). Height and leg length may
reflect the dynamic properties of the arterial tree, with short
height increasing the systolic peak because of the early
return of reflected arterial pulse waves (64). Two studies that
controlled for current height found that this made very little
difference to effect estimates (34, 43), suggesting that height
may not be on the causal pathway between breastfeeding and
blood pressure. Alternatively, breastfeeding may program
both growth rate and the formation of blood pressure control
mechanisms (70).

Conclusions

Breastfeeding is inversely associated with blood pressure,
but the possibility of publication bias and residual
confounding cannot be excluded. If causal, the observed
reduction in blood pressure associated with breastfeeding
may have a small, but important effect on public health,
especially in populations where early bottle feeding is
common.

ACKNOWLEDGMENTS

R. M. M. is a Wellcome Trust research training fellow in
clinical epidemiology.

All three authors developed the hypothesis. R. M. M.
acquired the data, performed the analysis, wrote the first

draft of the paper, and coordinated its completion under the
supervision of G. D. S. and D. G. The first draft was signifi-
cantly revised after comments from these two authors. All
authors contributed to and approved the final version.

Help in developing the electronic search of the MEDLINE
and EMBASE databases was provided by Margaret Burke,
Cochrane Heart Group Trials Search Coordinator.

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APPENDIX

MEDLINE Search Strategy for Systematic Review

Am J Epidemiol 2005;161:15–26

http://aje.oxfordjournals.org/

Breastfeeding in Infancy and Blood Pressure in Later Life: Systematic Review and Meta-Analysis

Richard M. Martin, David Gunnell, and George Davey Smith
From the Department of Social Medicine, University of Bristol, Bristol, United Kingdom.
Received for publication January 29, 2004; accepted for publication June 25, 2004.
The influence of breastfeeding on blood pressure in later life is uncertain. The authors conducte…
blood pressure; bottle feeding; breast feeding; cardiovascular system; hypertension; infant nutri…
Abbreviation: CI, confidence interval.
MATERIALS AND METHODS
Included studies
Data sources
Statistical analysis
Sensitivity analysis
RESULTS
Description of studies
TABLE 1.
Studies reporting on associations between method of infant feeding and blood pressure beyond 12 m…
FIGURE 1.�Summary of outcomes of studies retrieved for analysis, 1966–2004.
Definitions of breastfeeding
Breastfeeding and systolic blood pressure
FIGURE 2.�Mean difference (95% confidence interval) in systolic blood pressure (mmHg) for infants…
Breastfeeding and diastolic blood pressure
FIGURE 3.�Mean difference (95% confidence interval) in diastolic blood pressure (mmHg) for infant…
Small study effects
FIGURE 4.�Begg’s funnel plot (with pseudo 95% confidence limits) for studies reporting on the ass…
Excluded studies
TABLE 2.
Studies relating breastfeeding to blood pressure levels in infancy (before 12 months of age), by …
Blood pressure in infancy
DISCUSSION
Chance, bias, and confounding
Relevance to contemporary cohorts
Population health implications
Mechanisms
Conclusions
ACKNOWLEDGMENTS
REFERENCES
APPENDIX
MEDLINE Search Strategy for Systematic Review

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