• Posted May 10, 2023

Overweight Boys May Be Grow Up to Be Less Fertile Men

Men who were overweight as boys may have infertility issues in adulthood, according to new research.

Researchers studying the issue of male infertility, often a mystery, looked at health data from 268 young people between 2 and 18 years of age. They had been referred to the University of Catania in Sicily for weight control.

"Although the prevalence of childhood obesity is increasing worldwide, the impact of obesity and associated metabolic disorders on testicular growth is not well known,"said study co-author Dr. Rossella Cannarella, a research fellow at the Glickman Urological & Kidney Institute in Cleveland.

For the study, published May 10 in the European Journal of Endocrinology, the researchers collected data on testicular volume, body mass index and insulin resistance. They found that boys with normal weight had testicular volume that was 1.5 times higher than those who were overweight or obese before puberty.

Young people in the study with normal insulin levels had 1.5 to 2 times higher testicular volume compared to those with hyperinsulinemia, which is often associated with type 2 diabetes.

Lower testicular volume is a predictor of poorer sperm production in adulthood, the researchers said.

About 48 million couples struggled with infertility in 2010, according to the World Health Organization. Male infertility is a contributor in about half of all infertility cases, researchers said, but its cause is often a mystery.

Existing research has pointed to decreasing sperm concentration and total sperm count over the past 40 years. Over that time, childhood obesity has increased worldwide to 42 million.

Researchers also noted that surveys from Italy have found testicular shrinkage in almost a quarter of 18- and 19-year-olds. Various environmental conditions, including exposure to endocrine-disrupting chemicals, and more sedentary lifestyles have been among the changes over the past few decades.

Researchers who produced this new study said weight loss in childhood could help prevent infertility later in life.

"In this study, we found that being overweight or obese was associated with a lower peri-pubertal testicular volume," Cannarella said in a journal news release, adding that obesity-related conditions including insulin resistance have been found to influence testicular volume before and after puberty.

"Therefore, we speculate that more careful control of body weight in childhood could represent a prevention strategy for maintaining testicular function later in life," she said.

More information

The U.S. National Institutes of Health has more on male infertility.

SOURCE: European Journal of Endocrinology, news release, May 10, 2023