The Relationship of Pre-pubertal BMI Status to Post-pubertal BMI Status: An 8 Year Cohort Study

Objective: To investigate body mass index (BMI) percentile trends in a longitudinal cohort through puberty and to identify factors associated with post-pubertal overweight/obese BMI percentile status. Methods: A retrospective cohort study of 760 children over eight years in a large academic healthcare system. Each child had one pre-puberty visit during 1999-2000 while aged 6-11 and one post-puberty visit during 2006-2007. Demographic and BMI data was collected on all subjects. For pre-pubertal overweight/obese subjects (BMI ≥ 85th percentile), additional data was reviewed. Results: Overall, rates of overweight/obesity increased from 39% to 46% from pre to post puberty, respectively. Neither race/ethnicity nor gender was associated with increased post-pubertal BMI percentile. Twenty percent of children with normal pre-puberty BMI percentile progressed to being overweight/obese. A high normal pre-pubertal BMI (72nd-84th percentile) was predictive of post-pubertal overweight/obese status. Having a post-puberty overweight/ obese BMI percentile was 20.4 times more likely if the pre-puberty BMI was ≥ 85th percentile. Pre-puberty overweight/ obese subjects were less likely to be obese post-puberty if they met with a nutritionist/dietician. Few overweight/obese subjects had a provider-documented diagnosis of overweight/obese pre-puberty and weight related co-morbidities doubled through puberty, but neither influenced post-pubertal BMI percentile status. Conclusions: A pre-pubertal BMI at high normal (72nd-84th percentile), or a BMI ≥ 85th percentile, but not race/ ethnicity or gender, are risk factors for an overweight/obese BMI status post-puberty. Most children do not out grow their overweight/obese status through puberty, signifying the need for improved, earlier identification of and intervention for the pre-pubertal overweight/obese children and those near overweight (BMI ≥ 72nd percentile).