Mínguez-Alarcón L, et al. - Researchers investigated the association between self-reported type of underwear worn and markers of testicular function among men at a fertility center. Outcomes of this study revealed higher sperm concentration and total count, and lower FSH levels among men who reported most frequently wearing boxers vs men who did not.

Methods

• In this cross-sectional study, researchers included 656 male partners of couples seeking infertility treatment at a fertility center (2000–2017).
• Via a take-home questionnaire, they collected self-reported information on type of underwear worn.
• They followed World Health Organization guidelines to analyze semen samples.
• Reproductive hormone levels and sperm DNA damage were assessed using enzyme immunoassays and neutral comet assays, respectively.
• The association between underwear type and testicular function was evaluated via fitting linear regression models, adjusting for covariates and accounting for multiple semen samples.

Results

• Median (interquartile range) age of the men was 35.5 (32.0, 39.3) years and BMI was 26.3 (24.4, 29.9) kg/m².
• Boxers were reported to be frequently worn by about half of the men (53%; n = 345).
• Compared to men who reported not primarily wearing boxers, men who reported primarily wearing boxers had a 25% higher sperm concentration (95% CI = 7, 31%), 17% higher total count (95% CI = 0, 28%) and 14% lower serum FSH levels (95% CI = −27, −1%).
• They identified an inverse correlation of sperm concentration and total count with serum FSH.
• Furthermore, after adjustment for serum FSH, attenuation of the differences in sperm concentration and total count according to type of underwear was noted.
• They observed no associations with other measured reproductive outcomes.