Gene-environment interplay in the development of overweight during adolescence
Overweight and obesity have become increasingly common among young people over recent decades. This is concerning because overweight and obesity are associated with many physical health conditions and psychosocial difficulties.To improve prevention, we need to understand why some young people develop overweight while others do not. This dissertation examined how genetic and environmental factors jointly shape individual differences in BMI and overweight from childhood to early adulthood. It combined longitudinal cohort analyses with a systematic review and meta-analysis of previous research.
The findings show that both genetic and environmental factors contribute to individual differences in BMI and overweight during adolescence. Aspects of the family environment, specifically feeding practices and socioeconomic status, were associated with adolescents’ overweight development after accounting for genetic risk. Robust evidence that environmental factors attenuate or exacerbate the influence of genetic predisposition during this developmental period was limited.These findings emphasize that overweight among young people cannot be reduced to individual choices or parental behavior. Adolescent overweight is therefore best understood in relation to both genetic predisposition and the circumstances in which young people grow up.Further research is needed to better understand which environmental factors matter, for whom, and at what point in development. This knowledge could inform prevention and contribute to a more nuanced societal debate about overweight.