Maternal mental health at 5 years and childhood overweight or obesity at 11 years: evidence from the UK Millennium Cohort Study

Background/objectives Maternal psychological distress is associated with a range of adverse child outcomes. We sought to determine whether children's exposure to medium or severe distress at 5 years was associated with increased risks of overweight and obesity when they were aged 11 years. We also investigated whether any association was attenuated after accounting for potential confounding and mediating factors. Subjects/methods We analysed data from the UK Millennium Cohort Study, a nationally representative sample with data collected throughout childhood, imputing missing covariates (analytic sample: n = 9206). Multinomial regression was used to examine whether maternal psychological distress (Kessler-6 scale, using medium and severe score thresholds) at 5 years of age predicted children's objectively measured overweight and obesity at 11 years, adjusting for sex and ethnicity. We then carried out a series of models incorporating potential confounders (early life and socio-demographic, recorded at 9 months) and mediators (physical activity and dietary factors, at 7 years) in turn, and then simultaneously. Results A third of mothers reported distress when their child was aged 5 years (29% medium; 4% severe distress), and over a quarter of children were overweight at 11 years (22% overweight; 6% obese). Risks of obesity at 11 years increased with severity of maternal distress at 5 years (medium distress: relative risk ratio (RRR) = 1.43, 95% confidence interval [CI] 1.17-1.75; severe RRR = 2.27, CI 1.42-3.63). Adjusting for each set of explanatory factors in turn (particularly early years and socio-demographic confounding factors) reduced but did not eliminate these elevated risks. However, risks were attenuated in the fully adjusted model (medium: RRR = 1.14, CI 0.92-1.41; severe: RRR = 1.26, CI 0.75-2.11). Conclusions We demonstrated that maternal psychological distress, particularly if severe, at 5 years was associated with risk of obesity (but not overweight) at 11 years. Accounting for potential explanatory factors attenuated this association to non-significance, suggesting a range of mechanisms may be implicated. Future research should seek to disentangle the potentially complex pathways linking explanatory factors, maternal distress and child obesity.