Parent-child resemblance in BMI and obesity status and its correlates in China

Objective: Examine mother-son, mother-daughter, father-son and father-daughter resemblance in weight status, and potential modifying effects of socio-demographic and childcare characteristics. Design: Cross-sectional study. Setting: School. Participants: 1973 school-age children and their parents from five mega-cities across China in 2017. Results: Pearson correlation coefficients (r) for BMI of father-son, father-daughter, mother-son and mother-daughter pairs were 0·16, 0·24, 0·26 and 0·24, respectively, while their weighted kappa coefficients (k) were 0·09, 0·14, 0·04 and 0·15, respectively. Children aged 6-9 years (r ranged from 0·30 to 0·35) had larger BMI correlation with their parents than their counterparts aged 10-14 years or 15-17 years (r ranged from 0·15 to 0·24). Children residing at home (r ranged from 0·17 to 0·27) had greater BMI correlations with their parents than children residing at school/other places. BMI correlation coefficients were significant if children were mainly cared for by their mothers (r ranged from 0·17 to 0·29) but non-significant if they were mainly cared for by others. Only children who ate the same meal as their parents 'most times' (r ranged from 0·17 to 0·27) or had dinner with their parents 'at most times' (r ranged from 0·21 to 0·27) had significant BMI correlation with their parents. Similarly, children who had dinner with their parents 'most times' but not 'sometimes,' had significant BMI correlation coefficients. Conclusions: Parent-child resemblance in weight status was modest and varied by child age, gender, primary caregiver, whether having similar food or dinner with parents in China.