Childhood obesity is rising, and the health issues that often accompany it — diabetes, metabolic problems and high blood pressure — are well-known.
Now it appears there’s a new risk that won’t show up until kids are older: male infertility.
It is estimated that infertility affected the lives of over 48 million couples in 2020. Male infertility is often overlooked, or at least seen as secondary to women’s fertility, but it is believed to be a factor contributing to couple infertility in about half of all cases.
The reason for male infertility is unclear in many instances, but a recent study found that overweight boys tend to have lower testicular volume, putting them at risk for infertility in adulthood.
Italian surveys have found that almost a quarter of young men aged 18 to 19 showed signs of a loss of testicular volume.
The 268 children and adolescents in the retrospective, cross-sectional study of children and adolescents aged 2 to 18 years had been referred to the Unit of Pediatric Endocrinology at the University of Catania, in Sicily, for help with weight control. When investigators collected data on them — age, body mass index, testicular volume and insulin resistance — they noticed that boys with normal weight had a 1.5 times higher testicular volume compared to those who were overweight or obese before hitting puberty.
Children and adolescents in the study who had normal insulin levels also had testicular volumes that were 1.5-2 times higher compared to those with higher insulin levels in their blood, a condition known as hyperinsulinemia and which is often associated with type 2 diabetes. Overweight or obese boys with hyperinsulinemia or insulin resistance had lower testicular volume than their healthy peers.
The exact impact of obesity and obesity-related metabolic disorders on testicular growth in childhood is not known, but Italian surveys have found that almost a quarter of young men aged 18 to 19 showed signs of testicular hypotrophy, in which the testicles shrink, but not the scrotum, a factor which could put their future fertility at risk.
Various environmental conditions such as exposure to endocrine-disrupting chemicals and lifestyle choices such as sugar consumption and being sedentary have also risen over the past few decades. These, too, could contribute to men’s fertility.
“[W]e found that being overweight or obese was associated with a lower peri-pubertal testicular volume,” Rossella Cannarella, one of the authors, explained. “In addition, obesity-related comorbidities, such as hyperinsulinemia and insulin resistance, have been found to influence testicular volume in pre- and post-puberty.” Since lower testicular volume predicts poorer sperm production in adulthood, the University of Catania researchers believe that weight loss could help patients avoid infertility later in life.
The study is published in the European Journal of Endocrinology.