Evaluating Coincident Relationships Between Obesity Incidence and Normal Weight Incidence From Birth Through...

We examine the concurrent relationship between obesity incidence and normal weight status incidence and prevalence in children between 9 months and kindergarten.

Multistage, probability sample from the Early Childhood Longitudinal Study-Birth cohort.

United States.

Representative sample of US preschool children (n = 9950) followed from birth through kindergarten.

From direct, anthropometric measures, we reported prevalence and incidence rates across 4 follow-up periods.

In addition to prevalence and incidence rates, we reported risk ratios based on multiple definitions and estimated predicted probabilities of obesity and normal weight status using clinically meaningful body mass index (BMI)-for-age percentiles.

Obesity prevalence (13%-20%) was much smaller than normal weight status prevalence (66%-70%). Lower socioeconomic status, Hispanic, and non-Hispanic black children had greater risk of obesity. During 9 months to kindergarten, obesity incidence decreased two-thirds (15.6%), while normal weight status incidence decreased almost one-half (44.6%). Coincidently, normal weight status incidence (ranged from 23% to 45%) was consistently and substantially higher than obesity incidence (ranged from 5% to 15%). During 4 years to kindergarten, the obesity risk for overweight children was 13 times higher than that for normal weight status children.

Overall rates of obese and normal weight incidence were substantial at 9 months, trended lower, but remained high through kindergarten. At 4 years to kindergarten, children with relatively high initial BMI were very likely to become obese but far less likely to achieve normal weight status.