New University of Michigan study finds boys with higher body fat more likely to delay puberty

Posted: Feb 1, 2010 at 4:00 PM [Feb 1, 2010]

High body fat may delay the onset of puberty in boys, University of Michigan researchers say.

A new report, published in this month’s issue of the Archives of Pediatrics and Adolescent Medicine, found boys with a higher body mass index were more likely to reach puberty at a later age than those with a lower BMI.

Researchers followed 401 boys from diverse socio-economic backgrounds in 10 regions of the United States and measured their height and weight from 2 to 12 years old. They found 14 percent of the boys with a high BMI had a later onset of puberty, compared with 13.3 percent of boys with an intermediate BMI and 7 percent of boys with a low BMI.

U-M Pediatric Endocrinologist Joyce Lee, the study’s lead author, said the findings are different than similar studies done on girls.

“Heavier girls tend to develop earlier, rather than later,” she said in a statement. “Our study shows that the relationship between body fat and timing of puberty is not the same in boys as it is in girls."

Lee said with childhood obesity rates more than doubling in the U.S. during the past 20 years, it has become increasingly important to understand how excess body fat affects children’s growth and development.

This research is one of the few longitudinal studies examining the connection between body fat and puberty on boys. But, Lee said, more studies are still needed.

“Our findings have important implications for understanding sex differences in physiological mechanisms of puberty," Lee said in a statement. "Given the recent childhood obesity epidemic, additional studies are needed to further investigate the epidemiological link between fat and pubertal initiation and progression in boys as well as physiological mechanisms responsible."

Erica Hobbs can be reached at ericahobbs@annarbor.com.