Background

Maternal early- / pre-pregnancy BMI and gestational weight gain have been shown to be positively associated with offspring greater adiposity in later life in numerous prospective cohort studies, including in previous publications from ALSPAC. However, the extent to which this association is causal or due to bias (including publication bias, where studies that show a positive association are more likely to be published) is unclear.

We want to explore this by undertaking an individual participant meta-analysis in all birth cohorts (globally) that we can identify and that have relevant data. Our aim is that this should allow us to obtain precise estimates that are less likely to be influenced by publication bias than undertaking a systematic reivew and meta-analysis of published studies.

Further we want to compare association of maternal exposures with offspring outcomes to the same associations in fathers in order to determine whether there is evidence of specific maternal associations, which would support a intrauterine causal effect.

Aims and objectives

1. To undertake an independent participant data meta-analysis of the association of maternal pre-pregnancy BMI and gestational weight gain with offspring adiposity and body composition.

2. To compare associations of maternal exposures with offspring outcomes to the same associations of paternal exposures to explore whether associations in mothers are likely to represent intrauterine causal mechanisms

3. To explore the extent to which any associations might be mediated by birth characterists and later offspring activity and energy intake