Obesity in Early Childhood

Identifying Risk for Obesity in Early Childhood

Philip R. Nader, MD(a), Marion O'Brien, PhD(b), Renate Houts, PhD(c), Robert Bradley, PhD(d), Jay Belsky, PhD(e), Robert Crosnoe, PhD(f), Sarah Friedman, PhD(g), Zuguo Mei, MD(h), Elizabeth J. Susman, PhD(i) for the National Institute of Child Health and Human Development Early Child Care Research Network

a) Division of Community Pediatrics, University of California, San Diego, California;
b) Department of Human Development and Family Studies, University of North Carolina, Greensboro, North Carolina
c) Statistics and Epidemiology, Research Triangle Institute, Research Triangle Park, North Carolina
d) Center for Applied Studies in Education, University of Arkansas, Little Rock, Arkansas
e) Institute for Study of Children, Families and Social Issues, Birkbeck University of London, London, United Kingdom
f) Department of Sociology and Population Research Center, University of Texas, Austin, Texas
g) National Institute of Child Health and Human Development, Bethesda, Maryland
h) Division of Nutrition and Physical Activity, Centers for Disease Control and Prevention, Atlanta, Georgia
i) Department of Biobehavioral Health, Pennsylvania State University, University Park, Pennsylvania

OBJECTIVES. Our aim with this study was to assist clinicians by estimating the predictive value of earlier levels of BMI status on later risk of overweight and obesity during the middle childhood and early adolescent years.

METHODS. We present growth data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development, a longitudinal sample of 1042 healthy US children in 10 locations. Born in 1991, their growth reflects the secular trend of increasing overweight/obesity in the population. Height and weight of participating children in the study were measured at 7 time points. We examined odds ratios for overweight and obesity at age 12 years comparing the frequency with which children did versus did not reach specific BMI percentiles in the preschool- and elementary-age periods. To explore the question of whether and when earlier BMI was predictive of weight status at age 12 years, we used logistic regression to obtain the predicted probabilities of being overweight or obese (BMI 85%) at 12 years old on the basis of earlier BMI.

RESULTS. Persistence of obesity is apparent for both the preschool and elementary school period. Children who were ever overweight (>85th percentile), that is, 1 time at ages 24, 36, or 54 months during the preschool period were >5 times as likely to be overweight at age 12 years than those who were below the 85th percentile for BMI at all 3 of the preschool ages. During the elementary school period, ages 7, 9, and 11 years, the more times a child was overweight, the greater the odds of being overweight at age 12 years relative to a child who was never overweight. Sixty percent of children who were overweight at any time during the preschool period and 80% of children who were overweight at any time during the elementary period were overweight at age 12 years. Follow-up calculations showed that 2 in 5 children whose BMIs were 50th percentile by age 3 years were overweight at age 12 years. No children who were <50th>6 times more likely to be overweight at age 12 years than those <50th>85th percentile, as well as with BMIs in the high reference range are more likely than children whose BMI is <50th percentile to continue to gain weight and reach overweight status by adolescence. Pediatricians can be confident in counseling parents to begin to address the at-risk child's eating and activity patterns rather than delaying in hopes that overweight and the patterns that support it will resolve themselves in due course. Identifying children at risk for adolescent obesity provides physicians with an opportunity for earlier intervention with the goal of limiting the progression of abnormal weight gain that results in the development of obesity-related morbidity.

Key Words: BMI • childhood obesity • longitudinal growth

Abbreviations: CDC—Centers for Disease Control and Prevention • NICHD—National Institute of Child Health and Human Development • OR—odds ratio • CI—confidence interval

PEDIATRICS Vol. 118 No. 3 September 2006, pp. e594-e601 (doi:10.1542/peds.2005-2801)