SUMMARY
Epidemiological evidence indicates that early life factors are important for obesity development but there are gaps in knowledge regarding the impact of exposures during pregnancy and early life, especially in South Asian children. There is a corresponding lack of evidence to guide development of culturally-appropriate, obesity prevention programmes. This paper describes the methodology and characteristics of participants in Born in Bradford 1000 (BiB1000), a nested cohort of the Born in Bradford prospective birth cohort. BiB1000 aims to enable a deep and extensive understanding of the predictors and influences of health-related behaviours to develop a culturally-specific obesity prevention intervention. 1,735 mothers agreed to take part in detailed assessments focused on risk factors of obesity. Of these, 1,707 had singleton births. Data were collected from the families during pregnancy, at birth and when the infant was aged 6, 12, 18, 24 and 36 months. Approximately half of the mothers (n=933) are of South Asian ethnicity; of which, just under half were born in the UK. Prevalence of obesity in BiB1000 is similar to the full BiB cohort and to UK national averages. In addition to pre-specified hypothesised targets for obesity prevention, (e.g. parental feeding styles, diet and activity), BiB1000 is exploring qualitative determinants of behaviours andother exposures with a lesser evidence base (e.g. food environments, sleep, parenting practices). These data will enable a rich understanding of the behaviours and their determinants in order to inform the development of a culturally-relevant, childhood obesity prevention intervention.