OBJECTIVE: To estimate differences in skeletal maturity and stature from birth to age 18 years between individuals who are overweight vs normal weight in young adulthood. PATIENTS AND METHODS: Weight, length and height, and relative skeletal age (skeletal - chronological age) were assessed annually from birth to age 18 years in 521 subjects (255 women) in the Fels Longitudinal Study who were overweight or obese (body mass index (BMI) >25 kg m -2, n=131) or normal weight (n=390) in young adulthood (18-30 years). Generalized estimating equations were used to test for skeletal maturity and stature differences by young adult BMI status. RESULTS: Differences in height increased during puberty, being significant for girls at ages 10 to 12 years, and for boys at ages 11 to 13 years (P-values<0.001), with overweight or obese adults being ∼3 cm taller at those ages than normal weight adults. These differences then diminished so that by age 18 years, overweight or obese adults were not significantly different in stature to their normal weight peers. Differences in skeletal maturity were similar, but more pervasive; overweight or obese adults were more skeletally advanced throughout childhood. Skeletal maturity differences peaked at chronological age 12 in boys and 14 in girls (P-values <0.001), with overweight or obese adults being ∼1 year more advanced than normal weight adults. CONCLUSIONS: This descriptive study is the first to track advanced skeletal maturity and linear growth acceleration throughout infancy, childhood and adolescence in individuals who become overweight, showing that differences occur primarily around the time of the pubertal growth spurt. Increased BMI in children on a path to becoming overweight adults precedes an advancement in skeletal development and subsequently tall stature during puberty. Further work is required to assess the predictive value of accelerated pubertal height growth for assessing obesity risk in a variety of populations.
Bibliographical noteFunding Information:
This study was supported by National Institutes of Health Grants R01-HD012252 and R01-HD053685. We acknowledge the life-long contributions of the Fels Longitudinal Study participants, and the study staff members, without whose commitment and enthusiasm the work of the study could never have been completed. In particular, we would like to thank Frances Tyleshevski for her help in the creation of the data set, Carol Cottom for the skeletal age assessments, and the past and present Lifespan Health Research Center data collection team for their contributions. We also acknowledge Peter Hannan from the University of Minnesota for providing statistical consultation and advice.
- body height
- critical period
- longitudinal studies
- skeletal age measurement