Genetic predisposition to high BMI, ultra-processed food consumptions in childhood, and adiposity in young adulthood: a 17-year prospective cohort study of 3061 individuals

BACKGROUND: Observational evidence suggests ultra-processed food (UPF) may contribute to obesity, but some people who consume a larger amount of UPF remain at normal weight. This study examined whether childhood UPF consumption was associated with obesity in early adulthood and whether the association was modified by genetic susceptibility to body mass index (BMI). METHODS: This prospective cohort study included data from 3061 participants of the Avon Longitudinal Study of Parents and Children (ALSPAC) in England with follow-up from 7 to 24 years. UPF consumption was calculated from food diaries based on the NOVA classification. LDpred2 was used to construct a polygenic score (PGS) for body mass index (BMI). Linear regression models were used to estimate the association between UPF intake at 7 years and BMI at 24 years. The PGS-UPF interaction was examined to see whether genetic susceptibility modifies the association between childhood UPF consumption and early adulthood BMI. RESULTS: higher BMI at 24, after adjusting for BMI at 7, age, sex, ethnicity, physical activity, socioeconomic position, and total energy intake. There is evidence for PGS-BMI interaction (0.19; 95% CI 0.02-0.36), and the UPF-BMI association was only retained in children with the highest genetic predisposition to higher BMI (0.74, 95% CI 0.07-1.42) in the subgroup analysis. CONCLUSIONS: UPF consumption in childhood is only associated with early adulthood obesity among children more genetically predisposed to higher BMI.