Young Children's Weight Trajectories and Associated Risk Factors: Results From the Early Childhood Longitudinal Study-Birth Cohort

Purpose. To estimate the prevalence of US. children's overweight risk and obesity at age 9 months and at age 2 years, to assess weight changes between the two periods, and to examine relationships between weight status (i.e., normal, at risk, or obese) changes and demographic variables. Design. Analyses of children's early weight trajectories and related demographic characteristics from the Early Childhood Longitudinal Study Birth Cohort (ECLS-B) are presented. Setting. United States. Subjects. The 9-month-old (n = 8900) and 2-year-old (n = 7500) ECLS-B waves were used to generate nationally representative estimates of obese and at-risk children born in 2001. Measures. Measures included child's sex, race/ethnicity, socioeconomic status, community locale, geographic region, and weight status. Analysis. Logistic and multinomial logistic regression models were used to determine the odds of children's demographic characteristics being related to weight persistence, loss, or gain. Results. Approximately one-third of U.S. children were either at risk or obese at 9 months (31.9%) and at 2 years (34.3%). Some children were at greater risk (e.g., Hispanics and low socioeconomic status children), while others had reduced risk (e.g., females and Asian/Pacific Islanders). Additional results from two trajectory models generally corroborated patterns of status change due to weight gain. Conclusions. Between age 9 months and age 2 years, U.S. children consistently moved toward less desirable weight status. Obesity risk was not uniform across demographic subgroups, suggesting that health policy might focus on those children at greatest risk. (Am J Health Promot 2011;25 [3] : 190-198.)