Increasing rates of obese and overweight children in the US may be contributing to a delayed onset of puberty in boys, research says.

University of Michigan (U-M) researchers show that a higher body mass index (BMI) or height to weight ratio, during early and mid-childhood for boys is associated with delayed onset of puberty.

This is one of the first studies in the US to examine the association between weight status and timing of puberty in boys.

"We found that increased body fat 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," says U-M paediatric endocrinologist Joyce M. Lee, who led the study.

"Our study shows that the relationship between body fat and timing of puberty is not the same in boys as it is in girls," she says.

With childhood obesity rates more than doubling in the US during the past two decades, it has become increasingly important to better understand the ways in which excess body fat can impact children`s growth and development, she adds.

"Although there have been a number of studies looking at the link between body fat and puberty in girls, few studies have been performed in boys. The results of our study suggest that excess weight may lead to a later onset of puberty in boys," Lee says.

"Our findings have important implications for understanding sex differences in physiological mechanisms of puberty," says Lee, who is assistant professor in paediatrics and communicable diseases, according to a U-M release.

Lee and her colleagues studied 401 boys from diverse socioeconomic backgrounds in 10 regions of the US using data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development.

Source: IANS