ETHNIC DIFFERENCES IN PHYSICAL ACTIVITY, DIETARY INTAKE, OBESITY AND BLOOD ...

304 Pages·2015·1.46 MB·English

by  Gemma Knowles

ETHNIC DIFFERENCES IN PHYSICAL ACTIVITY,
DIETARY INTAKE, OBESITY AND BLOOD PRESSURE
AMONG YOUNG CHILDREN IN THE UK

By
GEMMA KNOWLES

A thesis submitted to
The University of Birmingham
for the degree of
DOCTOR OF PHILOSOPHY

Public Health, Epidemiology and Biostatistics
School of Health and Population Sciences
College of Medical and Dental Sciences
University of Birmingham
October 2014
University of Birmingham Research Archive

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ABSTRACT

Introduction: Early-life differences in cardiovascular risk factors could contribute to ethnic
differences in cardiometabolic disease in adulthood. The aim of this thesis was to investigate
ethnic differences in lifestyle factors, adiposity and blood pressure among 5-6 year old
children in the UK. Methods: Cross-sectional data on blood pressure, anthropometric
measures, sociodemographics, dietary intake, ethnicity, and objectively-measured physical
activity, were analysed (n=1470 consented children; 45% White British, 30% South Asian,
8% Black African/Caribbean). Results: Compared with White British children, South Asian
children had higher, and Black African/Caribbean children had similar or lower, levels of total
and central adiposity. Pakistani and Black African/Caribbean boys did more moderate-
vigorous physical activity, whereas South Asian girls did less compared with their White
British peers. South Asian and Black African/Caribbean children had lower or similar blood
pressure compared with White British children. Sodium intake was highest among Black
African children. Sugar intake was lower among all minority ethnic groups compared with
White British children. Conclusions: The findings highlight several early-life ethnic
differences which could plausibly contribute to cardiovascular health inequalities in
adulthood. Early childhood might offer a key opportunity to prevent or reduce ethnic
differences in cardiovascular and metabolic disease later in life.
I would like to dedicate this thesis to my grandparents,
Pauline and John Wilson.
ACKNOWLEDGEMENTS

I would like to say a massive thank you to everyone who has helped, supported, entertained
and put up with me over the last few years. First of all, thank you to my supervisors, Neil
Thomas and Peymane Adab, for giving me the opportunity to pursue this research, for guiding
me along the way, and for allowing me the freedom to pursue additional projects. Neil, a
special thanks for teaching me the art of the full-stop! I also owe a huge thank you to my
surrogate supervisors, Miranda Pallan and Emma Lancashire, for providing feedback on early
drafts and for answering a million and one questions!
To everyone on the WAVES team - Kiya, Emma P, Phillippa, Emma L, Jo, Tania, Laura,
Nicola (I really hope I haven’t missed anyone!) – for office banter, lots of ranting,
philosophical chats, ‘Britain Furst’, school road trips/dramas, office aerobics, silent disco
(!!!)… You are awesome and I love working with you. Special thanks go to Kiya for help
with Chapter 3. Thank you also to all of the schools, teachers, children and parents who
participated in the WAVES study.
To Ali, Fiona, Neha and Ying, for making my time at HKU so memorable. I miss it every
day! To my family, particularly my Aunt, Rachel, for taking in a homeless and moneyless
student for the last 4 months and for constant supplies of lemon drizzle! Thank you to Eiman
Moustafa, my Arabic tutor, and the rest of the class, for providing much-needed (and highly
entertaining) distraction from PhD life when things were progressing slowly.
I would also like to thank the girls (and Manners) at Edgbaston Hockey Club, and current and
past ‘Clique’ members, for the best hockey years ever! Thank you to my very close friend,
Sara Husseini, for everything she has done (and continues to do) for me – there are too many
things to list here! To my fellow ‘Triflers’, Viv, Jelly and Bostock, thank you for your
amazing friendship, patience (“fine time”), encouragement, entertainment, and travelling
adventures. I couldn’t ask for a better group of friends. Thanks also go to Dr Jim Green, for
epic chats and PhD rants over pints of ale and Guinness. Finally, I would like to say a huge
thank you to my partner, Holly, for unconditional love, support and encouragement, and for
putting up with the all-nighters during the final stages. I can’t thank you enough.
CONTENTS LISTING

• Publications and presentations
• Table of contents
• List of Figures
• List of Tables
• List of Abbreviations
PUBLICATIONS AND PRESENTATIONS

The four empirical chapters in this thesis are based on the following papers. The data
presented in these papers are baseline measurements from the West Midlands ActiVe lifestyle
and healthy Eating in School children (WAVES) study. Gemma Knowles contributed to all
stages of data collection and data entry, undertook extensive data cleaning and coding, and
performed all statistical analyses and written work presented in this thesis. The focussed aims
of these papers were formulated by Gemma Knowles. Peymane Adab and Neil Thomas
advised on data analyses and provided feedback on all written work. Where listed, the other
co-authors also advised on data analysis and paper editing.
1. Knowles G, Pallan MJ, Lancashire ER, Thomas GN, Ekelund U, Adab P, on behalf of
the WAVES study investigators. Ethnic differences in physical activity and sedentary
time among young children in the UK (in submission)
2. Knowles G, Kelleher K, Griffin T, Pallan MJ, Thomas GN, Lancashire ER, McGee E,
Cade J, Adab P, on behalf of the WAVES study investigators. Ethnic differences in
nutrient dietary intake among young children in the UK (in preparation)
3. Knowles G, Pallan MJ, Thomas GN, Lancashire ER, Adab P, on behalf of the
WAVES study investigators. Ethnic differences in body composition and fat
distribution among young children in the UK (in preparation)
4. Knowles G, Pallan MJ, Thomas GN, Lancashire ER, Adab P, on behalf of the
WAVES study investigators. Ethnic differences in blood pressure among young
children in the UK (in preparation)
In addition, the following papers, presentations and conference abstracts were produced
during the period of postgraduate study at the University of Birmingham.
Publications
1. Knowles G, Pallan MJ, Thomas GN, Barrett T, Cheng KK, Ekelund U, Adab P.
Physical activity and blood pressure in primary school children: a longitudinal study.
Hypertension. 2013; 61(1):70-5.
2. Knowles G, Ling FC, Thomas GN, Adab P, McManus AM. Body size perception and
body size dissatisfaction among young Chinese children in Hong Kong: a cross
sectional study. Public Health Nutr. 2014 May 20:1-8. [Epub ahead of print]
3. Ling FC, McManus AM, Knowles G, Masters RS, Polman RC. Do children
emotionally rehearse about their body image? J Health Psychol. 2013 Oct 30. [Epub
ahead of print] DOI: 10.1177/1359105313507965.
Revisions
1. Knowles G, Mellecker R, Adab P, Thomas GN, McManus AM. Validation and
calibration of the wrist- and waist-worn GENEA motion sensor in children (Under
revision)
2. Knowles G, Wing-Sze L, McManus AM, Thomas GN, Adab P, Ho SY, Lam TH.
Associations between the built-environment and physical activity among Hong Kong
youth (Under revision)
In preparation
1. Griffin T, Balanos G, Hemming K, Lancashire ER, Knowles G, Adab P. Fitness,
physical activity and BMI among 5-6 year old children.
2. Knowles G, Pallan MJ, Thomas GN, Lancashire ER, Adab P. Ethnic differences in
body image among UK primary school children: the WAVES study.
Conference Presentations
1. Knowles G, Pallan MJ, Lancashire ER, Thomas GN, Ekelund U, Adab P, on behalf of
the WAVES study investigators. Ethnic differences in physical activity and sedentary
time among UK primary school children. European Congress for Obesity 2014,
Sofia, Bulgaria (Oral)
2. Knowles G, Ling FC, Thomas GN, Adab P, McManus AM. Body size dissatisfaction
among young Chinese children in Hong Kong: a cross-sectional study. European
Congress for Obesity 2013, Liverpool, UK
3. Knowles G, Mellecker R, Adab P, Thomas GN, McManus AM. Validation and
calibration of the wrist- and waist-worn GENEA motion sensor in children. ISBNPA
2013, Ghent, Belgium
4. Knowles G, Wing-Sze L, McManus AM, Thomas GN, Adab P, Ho SY, Lam TH.
Associations between the built-environment and physical activity among Hong Kong
youth. Society for Behavioural Medicine 2013 San Francisco, US
Invited talks
1. Knowles G, Pallan MJ, Thomas GN, Barrett T, Cheng KK, Ekelund U, Adab P.
Physical activity and blood pressure in primary school children: a longitudinal study.
An Najah University, Palestine (December 2012)