Associations of behavioral, motivational, and socioeconomic factors with BMI among children and adolescents.

Background: Higher weight represents a significant health concern in youth and may be influenced by socioeconomic and behavioral factors. We investigated the relationship between BMI and parental education, nutritional health, eating culture, organized and non-organized physical activity (PA), motives for PA (weight loss/maintenance, enjoyment), and screen-time in children and adolescents.

Methods: 677 2- to 11-year-olds (young-age-group) and 464 12- to 20-year-olds (old-age-group) from Leipzig, a city in Germany, participated. We applied multivariate linear regression analyses to assess associations.

Results: BMI-SDS was negatively associated with parental education (young-age-group: b = -0.25, p < 0.001, old-age-group: b = -0.27, p = 0.02), non-organized PA (young-age-group: b = -0.23, p = 0.029), and PA enjoyment (young-age-group: b = -0.05, p = 0.01, old-age-group: b = -0.05, p = 0.038), but negatively with media use during dinner (old-age-group: b = 0.53, p < 0.001), PA for weight loss/maintenance (young-age-group: b = 0.15, p < 0.001, old-age-group: b = 0.12, p < 0.001), and screen-time (young-age-group: b = 0.11, p = 0.009, old-age-group: b = 0.09, p = 0.001). Significant interactions with age, sex and parental education were observed.

Conclusion: A lower BMI in children is associated with high parental education, screen-free eating, higher participation in non-organized PA and lower screen-time. While measures of motivation were limited and thus findings should be interpreted with caution, intrinsic motivation for PA is associated with lower BMI whereas extrinsic motivation for PA is associated with higher BMI.

Impact: In a German cohort of children and adolescents, lower BMI is associated with high parental education, less screen time, more participation in non-organized physical activity and less media use during dinner. Intrinsic and extrinsic motives for physical activity are directly linked to the weight status of children and adolescents. These associations are particularly strong in families with low/medium formal education.