Young children's weight trajectories and associated risk factors: results from the Early Childhood Longitudinal Study-Birth Cohort

Abstract

Purpose: To estimate the prevalence of U.S. 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.