The Obesogenic Home Environment, Appetite, and Weight in Childhood

The obesogenic home environment is thought to play an important role in shaping children’s food intake, physical activity, and screen-based sedentary activities – key energy balance behaviours deemed important for weight development. However, little is known about direct relationships between the home environment and children’s weight. There is also a lack of research examining how individuals’ appetite might interact with the obesogenic home environment to shape weight development. This thesis uses data from the Gemini twin cohort to address these gaps in knowledge. Paper One details a systematic review examining relationships between the home environment and adiposity in children ≤12 years. Consistent associations were observed between the home media environment and child adiposity. Paper Two updated and validated a comprehensive measure of the home environment for school-aged children and showed that children living in more obesogenic home environments had poorer diets, engaged in less physical activity, accrued more screen-time, and had higher BMI-SDS at age 12. Paper Three revealed strong tracking of the obesogenic home environment from ages 4-12 years, and that exposure to a more obesogenic home media environment predicted greater increases in child BMI-SDS from 4-12 years. Paper Four presents a systematic review and meta-analysis demonstrating robust cross-sectional and prospective relationships between appetite and adiposity in childhood. Paper Five applied the twin design to test the hypothesis that the heritability of appetite varies by obesogenic risk in the home environment. Findings suggested that the shared environmental influence on appetite was higher in lower-risk home media environments, suggesting that an environment with less access to media may buffer the genetic expression of an avid appetite. This thesis provides evidence for the role of the obesogenic home environment in children’s appetite and weight, and specifically highlights the home media environment as a potential target for future obesity prevention and intervention strategies.