The team followed the subjects through time, noting their health status up to about three years out from their diagnoses. They monitored whether the men developed metabolic or vascular disorders.

Compared with men without varicoceles, men with the condition had a significantly higher incidence of heart disease, the researchers found. They also had a higher incidence of diabetes and hyperlipidemia, or high concentrations of fat in their blood.

For the most part, only symptomatic varicoceles are treated in the clinic. Asymptomatic varicoceles — those that don’t cause pain or impair reproductive function — are only monitored. But the researchers wondered whether both types increase men’s risk of developing other diseases and decided to look closer at the data to answer this question.

The team categorized the men with varicoceles by the symptoms they showed, if any, and found that men with asymptomatic varicoceles had no increase in their incidence of heart disease, diabetes or hyperlipidemia relative to men without varicoceles. Only men with symptoms, especially fertility problems and scrotal pain, showed increased risk of developing these diseases.  

The results suggest that monitoring for asymptomatic varicoceles remains reasonable, said Eisenberg. “If it’s truly asymptomatic, observation remains appropriate,” he said.

Although the study produced strong results, it also had limitations, the researchers wrote. The MarketScan Database collects data from a subset of privately insured individuals and may not represent all American men. Those diagnosed with varicoceles are known to have sought out specialist care, which constricts the sample further. In addition, the data lack details about how the varicoceles were diagnosed and how specific symptoms were recorded, and follow-up data was limited to a few years after diagnosis; disease development beyond that window was not available.

In the last few decades, the rates of cardiac, metabolic and vascular diseases have increased across the United States. This study holds out the possibility that varicoceles may provide a window into the future health of men.

“The development of these diseases is usually pretty silent,” Wang said. “It’s interesting to think about ways to catch disease early, or see risk factors you can identify, to prevent their development or progression.”

Going forward, Eisenberg hopes to determine the specific role of varicoceles in metabolic and vascular disease. He said he has uncovered a strong correlation but needs to dig deeper to know if varicoceles play a causative role in these conditions. If they do, the question becomes whether varicocele treatment could help prevent later disease.

“While these results make a strong case that varicoceles are associated with higher risks of cardiovascular diseases and diabetes, we do not yet know if we will need to change our present management for the estimated 17 million U.S. men with varicoceles,” said Keith Jarvi, MD, director of the Murray Koffler Urologic Wellness Centre and head of urology at Mount Sinai Hospital in Toronto, who was not involved with the study. “The big question is, ‘Is a varicocele just a marker of men’s health or could repair of the varicocele actually improve men’s health in the long term?’”

Other Stanford co-authors of the study are urology resident Kai Dallas, MD; Laurence Baker, PhD, professor of health research and policy; and statistical programmer Shufeng Li.

The study did not receive outside funding. Stanford’s Department of Urology helped to support the work.