Obesity Linked to Later Puberty in Boys

ANN ARBOR, Mich.Higher body mass index (BMI) during early and mid-childhood for boys has been linked to later onset of puberty, according to a new study published in the February issue of the Archives of Pediatrics and Adolescent Medicine.

We found that increased body fatness is associated with a later onset of puberty in boys, the opposite of what we have seen in girls, as heavier girls tend to develop earlier, rather than later. Our study shows that the relationship between body fat and timing of puberty is not the same in boys as it is in girls, said University of Michigan Health Systems lead researcher pediatric endocrinologist Joyce M. Lee, MD, MPH, the studys lead author.

Researchers studied 401 boys from diverse socioeconomic backgrounds in 10 regions of the United States using data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development. The study recruited full-term singleton children born in 1991 in 10 geographic areas and measured their height and weight from ages 2 to 12 years.

The study examined childrens BMI trajectories, which is the way childrens body fatness changes over the course of childhood. Children were divided into low, intermediate and high BMI trajectories. Children in the low group were on the thinner side throughout childhood, while children in the high group were on the heavier side. Of boys in the low BMI trajectory group (91 boys), 7 percent had later onset of puberty. Of boys in the intermediate BMI trajectory group (196 boys), 13.3 percent had later onset of puberty. Of boys in the high BMI trajectory group (114 boys), 14 percent had later onset of puberty.