Born In BradfordNeil Small

Professor of Health Research

School of Health StudiesUniversity of Bradford

25 Trinity Road, Bradford, BD5 OBB

Tel: 01274 236456 Fax: 01274 236458

Email: N.A.Small@bradford.ac.ukwww.bradford.ac.uk/acad/health/research/pcg

.. What a cohort study is and why we are conducting one

.. Why Bradford is a good place to do such a study

.. Study objectives

.. What data we will collect and when

Study Benefits / Study Challenges

Cohort studies: background

• You are not pre-selecting a group to study• You can visit the same people over time.• You can consider the whole context of a life -

how far is it ethnicity, deprivation, genetics or behaviour that shape a persons health profile

If you do it in one place you can link findings with service provision

Existing cohort studies

• There are a wide range internationally• UK studies include – 1946 cohort (one weeks

births) – sample of 5362 followed up at intervals – now 21 times

• West of Scotland – 3 cohorts recruited in 1987 when aged 15, 35 and 55 – to be followed for 20 yearsMillennium cohort – 19000 babies born in 2000

• ALSPAC – Avon (Bristol) 14000 children born in 1991/2

Why Bradford?

• Diverse population

• Stable community

• One maternity unit

• Integrated health services

• Connected IT

• Enthusiasm

• Development of research infrastructure

Bradford Population

• Bradford has a population of around half a million• 22% of population are less than 15 compared to 18% in England

and Wales• Has a significant Asian population, mainly living in inner city areas

10% 8% 6% 4% 2% 0% 2% 4% 6% 8% 10%

0 to 4

5 to 9

10 to 14

15 to 19

20 to 24

25 to 29

30 to 34

35 to 39

40 to 44

45 to 49

50 to 54

55 to 59

60 to 64

65 to 69

70 to 74

75 to 79

80 to 84

85 plus

Male Female England & Wales

0

1

2

3

4

5

6

7

8

9

10

1993-1995 1994-1996 1995-1997 1996-1998 1997-1999 1998-2000 1999-2001 2000-2002 2001-2003

Rate

per

100

0 liv

e bir

ths

Bradford England & Wales

Infant Mortality Rate, Bradford and England and Wales

0

2

4

6

8

10

12

14

1993-1997 1994-1998 1995-1999 1996-2000 1997-2001 1998-2002 1999-2003

Rate

per

100

0 liv

e bi

rths

Most deprived

2nd most deprived

3rd most deprived

2nd least deprived

Least deprived

Infant Mortality by Deprivation Quintile within Bradford1993-97 to 1999-03

Comparative Infant Mortality Rates for Areas with Similar Populations to Bradford

Infant Mortality Rate

0

2

4

6

8

10

12

14

16

18

1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002

Rat

e

Kirklees MCDBlackburn with

Darwen UAPendle CDPreston CD England and

WalesBradford MCD

Comparative Infant Mortality Rates for Areas with Similar Levels of Deprivation

Infant Mortality Rate

0

2

4

6

8

10

12

1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002 1999-2001 2000-2002

Rat

e

Bradford MCD Rochdale MCD Mansfield CDDoncaster MCDLeicester UA England and Wales

Low birth weight (less than 2500g) rate by ward 1993 -

2003

MATERNAL

DIET

FETAL

GENOME

UTEROPLACENTAL BLOOD FLOW

PLACENTAL TRANSFER

N u t r i e n t d e m a n d e x c e e d s s u p p l y

F E T A L U N D E R N U T R I T I O N

BRAIN SPARING ALTERED BODY COMPOSITION

DOWN REGULATION OF GROWTH

EARLY MATURATION

IMPAIRED DEVELOPMENT: BLOOD VESSELS, LIVER, KIDNEYS, PANCREAS

INSULIN/IGF-1 SECRETION AND SENSITIVITY

CORTISOL MUSCLE

HYPERLIPIDAEMIAHYPERTENSION

CENTRALOBESITY

INSULINRESISTANCE

Type 2 diabetes and CHD

Visual impairment

58% Pakistani children vs 29% White British children

Schwarz et al. Eye 2002;16:S30-34

Deafness

4.7 per 1000 Pakistani children vs 1.4 per 1000 others

Parry G. BACDA report 1996

Cerebral Palsy

5.48 per 1000 in Pakistani children vs 3.18 per 1000 in others

Sinha et al Dev Med Child Neurol 1997 39:259-262

Childhood disability

District Number of cases

(total 736)

Bradford 50

Birmingham 31

East London & City 25

East Riding 22

Berkshire 19

Bundey and Aslam 1993 Eur J Hum Genet 206-219

Empirical risk of death or serious disease

European (n = 2,241) Consanguineous Pakistani (n = 656)

Rate 3.7% (2.92-4.48) 10.2 (7.9-12.5)

Platform and nested studies • We have started recruiting pregnant mothers in March

and babies in May

• We will recruit all newborn babies and their parents born in BRI or under the care of the BRI over 30 months (target numbers – 10000)

A platform study: Most data for the study will be routinely collected data – health history, demographics, weight, blood samples etc. This will be supplemented with some specific questions eg more on maternal diet, more on home circumstances.

“Nested” studies – specific research questions that use the cohort as the source of their study population.

Research aims

– To explore the association between specific risk factors and exposures in pregnancy and infancy with infant mortality.

– To describe the differences in foetal growth and birth weight between ethnic groups and to investigate the causes of low birth weight in babies of South Asian origin

– To explore the effect of chemical exposure (air/water/diet) during pregnancy on the intrauterine growth

– To determine the incidence, causes and predictive factors for congenital abnormalities

Further research– To investigate the association between dietary

exposure to chemicals with carcinogenic and immunotoxic properties with childhood cancer and immune disorders.

– To study infant growth and investigate the effect of postnatal growth on childhood obesity and markers of cardiovascular disease in childhood.

– To describe social and ethnic differences in health status and the effects of ethnic density on health status and pregnancy outcomes.

Data collected• Demographic/socio-economic• Family history• Lifestyle factors – smoking/drugs/alcohol/exercise• Diet – modified food frequency + targeted questions

re exposures• Well being – GHQ 28• Social Capital (on sub set of 2000)• Clinical: antenatal and medical histories; drugs; BP;

weight; U/S scans.• Blood: routine; GTT; insulin; DNA extraction

Progress so far• Community awareness• NHS support• IT systems• Questionnaire design• Biobank • Advocacy committee• Fundraising• Feasibility study• Pilot phase

Benefits.

• Full use of routinelycollected data

• Growth of research activity/ capacity/ skills and opportunity in the city

• Focus for collaboration within health and with local government and community organisations.

Main challenges

• Funding• Data collection – information systems accessible

and compatible• Differential recruitment and drop-out• Lack of enthusiasm from staff• Subject burden

• Reconciling long-term gains and short term “wins”