Overweight and obesity in childhood and risk of mental disorder: A 20-year cohort study

Objective: Very little is known about whether overweight and obese children have long-term risk for mental health problems. This study examined the association between overweight and obesity in childhood and DSM-IV mood, anxiety, and substance use disorders in young adulthood. Method: Participants in a national Australian school survey when aged 7–15 years in 1985 were re-interviewed 20 years later as young adults aged 26–36 years (1135 women, 1108 men). Body mass index (BMI) was calculated from measured height and weight in childhood and adulthood. Children were classified as overweight or obese based on a BMI ≥85th centile for age and sex-specific height and weight. Obesity in adulthood was defined as BMI of ≥30. Twelve-month DSM-IV diagnoses of mood, anxiety and substance use disorders were obtained from the Composite International Diagnostic Interview. The relative risk (RR) for each class of mental disorder was estimated for childhood overweight/obesity versus non-overweight, and for four weight trajectories: non-overweight in childhood and non-obese in adulthood; overweight in childhood and non-obese in adulthood; non-overweight in childhood and obese in adulthood; and overweight in childhood and obese in adulthood. Results: Childhood overweight and obesity was associated with an increased risk of mood disorder in adulthood (RR = 1.54, 95%CI 1.06–2.23, p = 0.03), with a similar risk observed among girls and boys. When weight in adulthood was taken into consideration, increased risk of mood disorder was observed only among overweight girls who were obese in adulthood (adjusted RR = 2.03, 95%CI 1.22–3.66, p = 0.006), with childhood overweight or obesity in non-obese adults not associated with any mental disorder. Conclusions: Childhood overweight may increase risk for mood disorder in adulthood, especially among overweight girls who become obese women. These results suggest that prevention of childhood overweight is equally important in both sexes for reducing risk of diagnosed mood disorder in adulthood