Longitudinal Changes in Weight Status from Childhood and Adolescence to Adulthood

To study the change in body mass index (BMI) from childhood and adolescence and development of obesity into adulthood.

We performed a longitudinal study of 480 individuals (49% male; 67% white) with height and weight measures in childhood (mean age 7 years), repeated in adolescence (mean age 16 years) and adulthood (mean age 39 years). Weight status in childhood was defined as low normal weight (0-<50 BMI percentile); high normal weight (50-<85 BMI percentile); overweight (85-<95 BMI percentile); obese (≥95 BMI percentile). Adult weight status was defined as normal weight (18.5-<25 kg/m²); overweight (25-<30 kg/m²); obese (>30 kg/m²).

Adult obesity (%) increased with weight status in childhood (low normal weight 17%; high normal weight 40%; overweight 59%; obesity 85%) and similarly with adolescence. Children in a lower category in adolescence than in childhood had lower risk of having adult obesity than did those who maintained their childhood category. Among adults with obesity, 59% (111 out of 187) were normal weight as children, with 75% (83 out of 111) from the high normal weight children; and 50% of adults with obesity were normal weight (n = 94/187) as adolescents, with 84% (81 out of 94) from the high normal weight adolescents. Only 6% of 143 normal weight adults had either overweight (n = 9) or obesity (n = 0) during childhood.

This study shows the high risk for adult obesity in children and adolescents who have overweight or obesity. A majority of adults with obesity had a 50-85 BMI percentile as children. Those who did not move to higher weight status between childhood and adolescence had lower probability of adult obesity.