A comprehensive Danish study revealed a potential association between semen quality and life span, in which men with higher sperm counts may live nearly 3 years longer compared with those with poorer semen parameters.

In the study, published in Human Reproduction, investigators followed 78,284 men for up to 50 years post–semen analysis, finding that men with a total motile sperm count exceeding 120 million could expect to live 80.3 years compared with 77.6 years among men with counts between 0 to 5 million—a difference of 2.7 years.

"We observed clear negative dose-response associations between all semen parameters and all-cause mortality," the study authors reported. "The associations were not explained by educational levels or diseases registered at the time of semen evaluation," they added.

The study, led by Lærke Priskorn, MD, of the Copenhagen University Hospital—Rigshospitalet, included men who underwent semen analyses between 1965 and 2015 as a result of reported couple infertility. During the median follow-up period of 23 years, 8,600 deaths (11.0% of participants) occurred.

All semen parameters—including volume, concentration, motility, and morphology—showed consistent negative associations with mortality in dose-response patterns. The relationship persisted even after adjusting for educational level and prior diagnoses.

For the total motile sperm count parameter, compared with men with counts exceeding 120 million (reference group), adjusted hazard ratios for all-cause mortality were:

• Azoospermia: 1.39 (95% confidence interval [CI] = 1.05–1.85)
• 0 to 5 million: 1.61 (95% CI = 1.42–1.83)
• 5 to 10 million: 1.38 (95% CI = 1.14–1.68)
• 10 to 40 million: 1.27 (95% CI = 1.13–1.42)
• 40 to 80 million: 1.16 (95% CI = 1.03–1.29)
• 80 to 120 million: 1.19 (95% CI = 1.06–1.34).

Notably, the investigators found that these associations remained robust even when excluding deaths occurring within 5 years of semen analysis, suggesting the relationship was not linked to reverse causality from existing health conditions affecting semen quality.

"Thus, some men with impaired semen quality may experience less healthy aging than men with better semen quality and could benefit from being identified at the time of semen quality evaluation," the study authors emphasized, adding that "finding relevant biomarkers to identify the subgroups of men at increased risk will be key to initiating relevant prevention strategies."

The study's strengths included its large sample size, extensive follow-up period, and ability to link semen quality data with comprehensive national registries. However, the investigators acknowledged limitations such as a lack of information on lifestyle factors and inability to distinguish between different types of azoospermia.

These findings suggested that semen quality may serve as a broader biomarker of general health and longevity, extending beyond its traditional role in fertility assessment.

The authors declared no conflicts of interest.