Childhood obesity is associated with infertility in men

Data published in the European Journal of Endocrinology suggest that children and adolescents with a higher body mass index (BMI), hyperinsulinemia, and insulin resistance exhibit diminished testicular volume compared with their peers, which increases their risk of developing infertility later in life.^1,2

Peri-pubertal boys considered to be at a normal BMI had testicular volume 1.5 times greater than that of boys considered to be overweight.

"Although the prevalence of childhood obesity is increasing worldwide, the impact of obesity and related metabolic disorders on testicular growth remains poorly understood. Our study discovered that being overweight or obese was linked with reduced testicular volume during the peri-pubertal stage,” said study author Rosella Cannarella, MD, PhD, in a news release on the findings.² “Additionally, obesity-related conditions such as hyperinsulinemia and insulin resistance have been shown to affect testicular volume during both pre- and post-pubertal stages. Thus, we believe that more thorough body weight control in childhood could serve as a preventive measure for preserving testicular function in adulthood." Cannarella is a clinical andrologist at the University of Catania in Italy.

In total, 268 male children and adolescents ranging from 2-18 years were included in the study. Data on testicular size, age, BMI, and insulin resistance were obtained retrospectively. Participants were categorized as pre-pubertal (< 9 years), peri-pubertal (9-14 years), and post-pubertal (14-16 years). Among all participants, 62 were considered a normal weight, 54 were overweight, 79 were obese, and 73 were severely obese.

Investigators observed that peri-pubertal boys considered to be at a normal BMI had testicular volume 1.5 times greater than that of boys considered to be overweight. There were no significant differences in testicular volume observed among the other age groups when data was grouped by BMI.

Data were then analyzed in regard to insulin levels, with an insulin level above 20 µIU/µL indicating hyperinsulinemia. Findings showed that pre- and post-pubertal children and adolescents with normal insulin levels had a testicular volume 1.5-2 times higher than that of participants with hyperinsulinemia, regardless of BMI. Conversely, peri-pubertal boys with normal insulin levels had significantly lower testicular volume compared to those with hyperinsulinemia.

Further, peri-pubertal boys with insulin resistance had a higher testicular volume than those without insulin resistance. However, post-pubertal participants with insulin resistance were found to have a significantly lower testicular volume than those without insulin resistance. There was no impact of insulin resistance on testicular volume found among participants less than 9 years.

“Since a lower [testicular volume] is predictive of worse sperm production, these results help to understand the reason for the high prevalence of testicular hypotrophy in young men. We speculate that more careful control of body weight in this time window could represent a prevention strategy to pursue the maintenance of testicular function later in life,” stated the authors.

They suggest that further studies are needed to confirm the findings, such as extending the follow-up to adulthood.

References

1. Cannarella R, Carusa M, Condorelli RA, Timpanaro TA, Caruso MA, La Vignera A, Calogero AE. Testicular volume in 268 children and adolescents followed-up for childhood obesity—a retrospective cross-sectional study. Eur J Endocrinol. Published April 5, 2023. Accessed May 24, 2023. doi:10.1093/ejendo/lvad033

2. Overweight boys more likely to be infertile men. News release. Oxford University Press. May 10, 2023. Accessed May 24, 2023. https://www.newswise.com/articles/obese-boys-at-risk-of-infertility?sc=mwhr&xy=10016681