Associations between family circumstance and weight status of Australian children.

OBJECTIVE: To examine associations between weight status and multiple indicators of family circumstance in Australian elementary school children.
METHODS: Data were combined from the 2001 Children's Leisure Activities Study (CLAS Study) and 2002/3 Health, Eating and Play Study (HEAP Study), involving 2520 children in Grades Prep (mean age 6 years) and 5-6 (mean age 11 years) in Melbourne, Australia. Children's body mass index (BMI) was calculated from measured height and weight. Weight status (non-overweight or overweight) was determined according to International Obesity Taskforce cut-off points and BMI was transformed to z-scores based on the 2000 US growth chart data. Parents reported family circumstance (number of parents in the home, marital status, presence of siblings, parental education, parental employment status, parental work hours [HEAP Study only]) and parental BMI. Regression analyses were conducted for the sample overall and separately for young girls, young boys, older girls and older boys.
RESULTS: Children in single-parent homes, those without siblings, and those with less educated mothers and fathers tended to have higher z-BMIs (p=0.002, p=0.003, p<0.001 and p<0.001, respectively) and were more likely to be overweight (p=0.003, p<0.001, p<0.001 and p=0.02, respectively). Associations were stronger for older children. Parental employment and work hours were not consistently associated with child weight status. The multivariable models did not demonstrate a cumulative explanatory effect (R(2)=0.02), except when maternal BMI was included (R(2)=0.07).
CONCLUSIONS: Individual measures of family circumstance were differentially associated with child weight status and appeared to be largely independent of other measures of family circumstance. Childhood overweight interventions may need to be tailored based on the age, gender, maternal BMI and family circumstances of the target group.