Boys with Overweight/Obesity Have Lower Testicular Volume, According to New Study

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Boys with overweight or obesity have lower testicular volume (TV) than their healthy peers, putting them at risk for infertility later in adulthood, according to a new study published in the European Journal of Endocrinology.

Findings also showed that boys with overweight/obesity and with obesity-related comorbidities, such as hyperinsulinemia and insulin resistance, had lower TV than their healthy peers.

“Since a lower TV is predictive of worse sperm production, these results help to understand the reason for the high prevalence of testicular hypotrophy in young men,” wrote researchers. “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.”

Infertility impacts both the psychological health and the economic and social aspects of millions of persons of childbearing age. According to a report from the World Health Organization (WHO), 48 million couples were affected by infertility in 2010. In most cases, however, the reason for male infertility is unclear, according to investigators. For example, a German study that evaluated the etiology of infertility in over 20 000 men referred to a fertility center found that no diagnosis could be made in approximately 70% of them.

Previous research also suggests decreasing sperm concentration and total sperm count over the past 4 decades. In parallel with the decrease in sperm count, the prevalence of childhood obesity has increased worldwide from 32 to 42 million, according to the WHO.

“Predictive modeling also indicates that 60% of children will be obese by the age of 35,” added investigators. “However, it is currently unknown whether childhood obesity can affect the testicular function and increase the risk of future infertility.”

Researchers conducted a retrospective, cross-sectional study to evaluate the impact of overweight, obesity, and related comorbidities, eg, hyperinsulinemia, and insulin resistance, on TV in prepubertal (aged <9 years), peripubertal (aged 9-14 years), and post-pubertal (aged 14-16 years) periods. Data on TV, age, standard deviation score of the body mass index (BMI), insulin, and fasting glycemia was collected.

A total of 268 boys were included in the study, of whom 206 were overweight or obese and 62 were normal weight.

Investigators observed that boys with normal weight had a significantly higher TV compared to those who were overweight or obese in peripubertal age. No difference was found in the other age ranges when data were grouped according to BMI.

Participants with normal insulin levels had significantly higher TV compared to those with hyperinsulinemia in pre- and post-pubertal age. Moreover, peripubertal boys with hyperinsulinemia had significantly higher TV compared to those with normal insulin levels.

Postpubertal participants with insulin resistance had lower TV and peripubertal boys had higher TV compared to those without insulin resistance. Investigators did not note a difference in prepuberty.

“If further studies will confirm our findings, there will be room for primary prevention of male infertility in pediatric clinics (pediatric andrology). Indeed, an accurate assessment of TV at each visit and the construction of TV growth curves would help identify early deviations in TV growth in children and adolescents,” concluded authors.

Reference: Cannarella R, Caruso M, Condorelli RA, et al. Testicular volume in 268 children and adolescents followed-up for childhood obesity—a retrospective cross-sectional study. Eur J Endocrinol. 2023;188:331-342.