Unclear relationship observed between male pubertal onset and weight

1. Using Tanner staging of genital development and testicular volume as markers for puberty, this study found that overweight white and African American boys had earlier onset of puberty compared with normal weight boys.

2. Obese white and African American boys had later onset of puberty compared with overweight boys. There was no significant relationship between onset of puberty and weight among Hispanic boys.

Evidence Rating Level: 2 (Good)

Study Rundown: The positive relationship between body fat and onset of puberty has been well established among girls. However, there are few studies assessing pubertal timing with body fat among boys. Existing studies have presented a mixed picture in the relationship between obesity and puberty among boys. Given the increasing prevalence of obesity among children and adolescents, elucidating any connection between body fat and pubertal timing becomes clinically relevant. This study uses the largest sample size to date to analyze any connections between normal, overweight, and obese boys and the onset of puberty. Overall, overweight white and African American boys were found to have earlier onset of puberty than normal weight boys, as indicated by Tanner staging of genital development (GD).  Obese white and African American boys were found to have later onset of puberty compared with overweight boys. There were no significant differences among Hispanic boys’ weight and pubertal development. Using testicular volume (TV) as a measure of pubertal development, puberty occurred earlier in overweight compared with normal weight white boys. While this study helps clarify the relationship between weight and puberty among boys, it is limited by its use of body mass index (BMI) as a measurement for adiposity. Future studies should incorporate a wider breadth of components that contribute to weight, such as body fat percentage.

Click to read the study published today in Pediatrics

Relevant Reading: Timing of puberty and physical growth in obese children: a longitudinal study in boys and girls

Study Author, Dr. Joyce M. Lee, MD, MPH, talks to 2 Minute Medicine: University of Michigan, Pediatric Endocrinology/Child Health Evaluation and Research Unit

“In girls, excess weight is associated with earlier onset of puberty, but for boys we saw a mixed picture, with overweight boys having earlier puberty and obese boys having later puberty.  This is novel information about the relationship between excess weight and timing of puberty, which underscores the need for more studies to understand these sex differences.”

In-Depth [cross-sectional study]: This study included data from the American Academy of Pediatrics’ Pediatrics Research in Office Settings study. A total of 3872 boys ages 6 through 16 years were included in the study (49.9% white, 25.8% black, 24.3% Hispanic). This study used calculated BMI from the data set to differentiate among weight categories, and clinician-assessed testicular volume (TV) and Tanner staging for genital development (GD) as pubertal indicators. Overweight white boys reached GD2 or greater at 9.3 years versus 10 years in normal weight boys (p = .008), and GD5 or greater at 14.5 years versus 15.2 years (p = .001). Obese white boys reached puberty later than overweight and normal weight boys GD5 or greater (15.4 years versus 14.5 and 15.2 years, respectively; p = .001). A similar trend was found among African American boys, with obese boys reaching puberty later compared to overweight boys (11.6 years vs 10.6 years for GD3; p = .0005, and 13.2 years vs 12.2 years for GD4; p = .002). There were no significant differences between timing of puberty and weight in Hispanic boys. Using TV, there was evidence of earlier puberty in overweight white boys compared to normal weight (10.3 years vs 11.3 years; p = .0001), but no significant differences among African American or Hispanic boys.

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