Risk of child obesity from parental obesity: analysis of repeat national cross-sectional surveys.

OBJECTIVE

To estimate the potential to reduce childhood obesity through targeted interventions of overweight households.

DESIGN

Cross-sectional nationally representative samples of the Scottish population.

SETTING

Households in Scotland during 2008 and 2009.

PARTICIPANTS

A total of 1651 households with parents and children aged 2-15 years.

MAIN OUTCOME MEASURES

The WHO cut-off points for adult body mass index (BMI): overweight (25 to <30 kg/m2) and obese (≥30 kg/m2). Overweight and obesity in childhood respectively defined as a BMI 85th to <95th percentile and ≥95th percentile based on 1990 reference centiles.

RESULTS

Thirty-two percent (600/1849) of children and 75% (966/1290) of adults were overweight or obese. Seventy-five percent (1606/2128) of all children lived with a parent who was overweight or obese. Among obese children, 58% (185/318) lived with an obese parent. The population attributable risk percentage of child obesity associated with parental obesity was 32.5%. Targeting obese households would require substantial falls in adult weight and need to reach 38% of all children; it might achieve a reduction in the prevalence of childhood obesity of 14% in these households (from 26% to 12%). Targeting parents with BMI ≥ 40 might reduce the overall prevalence of child obesity by 9%. Such an intervention would require large weight loss, consistent with approaches used for morbidly obese adults; it would involve 4% of all children and lead to a reduction in the prevalence of obesity in these households from 57% to 16%.

CONCLUSIONS

Family-based interventions for obesity would be most efficiently targeted at obese children whose parents are morbidly obese.