Sociodemographic associations of 4-year overweight and obese incidence among a racially diverse cohort of healthy weight 18-year-olds.

BACKGROUND: Emerging adulthood is a critical time for excess weight gain. Risk can be masked if recommended overweight and obesity cut-points for Asians are not employed.

OBJECTIVES: To determine the associations among sociodemographic factors and occurrence of overweight and obesity among normal weight 18-year olds.

METHODS: Normal weight (body mass index < 25 kg m-2 ; <23 kg m-2 for Asians) 18-year-old (9037 boys, 13 786 girls, 36% Hispanic, 34% non-Hispanic Whites, 10% Black, 5% Asian) members of a healthcare organization in 2008 were followed through 2012 to identify incidence of overweight and obesity. Hazard ratios (HR) and 95% confidence intervals (CI) were determined controlling for sex, race/ethnicity, neighbourhood education, neighbourhood income and smoking status.

RESULTS: After 3 years of follow-up, the HR for overweight was 1.28 (95% CI: 1.12, 1.45) in the lowest quartile of neighbourhood education compared with the highest. Asians and Pacific Islanders had greater risk of overweight (HR 2.89, 95% CI: 2.55, 3.28; HR 3.13, 95% CI 2.23, 4.38) than non-Hispanic Whites. Girls and Blacks were more likely to become obese than boys and non-Hispanic Whites, as were those living in the lowest neighbourhood education quartile and lower neighbourhood income quartiles.

CONCLUSIONS: Girls, Asians, Blacks and those living in low education and income neighbourhoods during adolescence are at risk for excessive weight gain trajectories.