Childhood Psychosocial Home Environment Modifies Genetic and Environmental Influences on Leisure-Time Physical Activity in Young Adulthood

Both genetic factors and childhood home environment explain individual differences in physical activity, but the interaction between them is poorly understood. This study aims to examine to what extent childhood psychosocial... [ view full abstract ]

Both genetic factors and childhood home environment explain individual differences in physical activity, but the interaction between them is poorly understood. This study aims to examine to what extent childhood psychosocial home environment modifies the relative roles of genetic and environmental influences of leisure-time physical activity in young adulthood. The participants were Finnish twins (N=3305) who self-reported their leisure-time physical activity at age 24. Psychosocial childhood home environment was assessed by twins at ages 12, 14 and 17 as well as by parents when the twins were 12 years old. Statistical modeling of gene-environment interaction was carried out with OpenMx software. Twins’ ratings of higher positive home atmosphere at ages 14 and 17 along with lower relational tensions at home at ages 12 and 14 predicted higher leisure-time physical activity levels in young adulthood (regression coefficients from 0.35 (95% CI 0.02–0.67) to 0.84 (95% CI 0.47–1.20). Twins’ perceived positive home atmosphere at age 14 significantly increased both the additive genetic variation (moderation effect 0.59 (95% CI 0.15–0.99)) and specific environmental variation (moderation effect 0.55 (95% CI 0.31–0.74)) of leisure-time physical activity in young adulthood. The lower levels of relational tensions rated by twins at ages 12 and 14 increased also the specific environmental variation in leisure-time physical activity (moderation effects 0.54 (95% CI 0.26–0.69) and 1.41 (95% CI 0.69–1.95), respectively). Similarly, parents’ ratings of lower levels of relational tensions were associated with the increase of specific environmental variation (moderation effect 0.44 (95% CI 0.02–0.62)) in twins’ physical activity, while the additive genetic variation was significantly decreased (moderation effect -0.41 (95% CI -0.80 to -0.02)). Our study suggests that warm and emotionally supportive childhood home environment can increase the level as well as genetic and environmental variability of leisure-time physical activity several years later.