According to research by Danish scientists, the quality of a man's sperm appears to be related to his life expectancy.
HDN Newsroom
Danish scientists analyzed samples from nearly 80,000 men and found that those who produced more than 120 million moving sperm per ejaculation lived two to three years longer than those who produced less than 5 million.
Men with the highest sperm quality lived an average of 80.3 years, while those with the worst quality lived an average of 77.6 years, according to the researchers in the Human Reproduction report.
"It really seems that the better the sperm quality, the longer the survival," said Dr. Lærke Priskorn, an epidemiologist at Copenhagen University Hospital, who led the study along with Dr. Niels Jørgensen, an andrologist at the same hospital.
The findings suggest that sperm quality is a broader reflection of a man's health status and how likely he is to contract a medical condition later in life. The researchers found across all its measurements that worse sperm quality was linked to early death.
The study ran from 1965 to 2015 and studied cases of men who had difficulty starting a family with their partner. The samples were evaluated for sperm volume, sperm concentration, sperm shape and percentage of motile sperm. While some men produced no sperm at all, others had very good sperm quality.
Using national registries, the researchers followed the men's health for up to 50 years after the sperm tests. There were 8,600 deaths during the follow-up period, accounting for 11% of the group. Almost 60,000 of the men provided sperm samples between 1987 and 2015 and their records contained more information, such as their level of education and any medical conditions they had been diagnosed with in the 10 years before the sperm analysis.
How to explain the association between poor sperm quality and premature death
The association between poor sperm quality and premature death cannot be explained by any diseases diagnosed in the decade before the test, nor by the educational level of men, which to some extent reflects socio-economic status and lifestyle (smoking, diet, exercise).
Priskorn said that since the data do not shed light on possible biological mechanisms, the answer may lie in the conditions in the womb.
In this scenario, factors affecting the baby's development would harm both the sperm and its broader health in later life.
Researchers now want to find out which diseases are more common in men with poor sperm quality. If specific conditions are identified, doctors could eventually advise men on preventative action if sperm analysis shows they are at risk.
In an accompanying editorial, Professor John Aitken, a reproductive biologist at Newcastle University in Australia, said:"If sperm are indeed a predictor of male health, the obvious question to ask is why."
Possible causes include genetic abnormalities in sex chromosomes, a weakened immune system, co-existing problems such as heart disease, lifestyle factors and pollutants. Aitken suspects a process called oxidative stress, where highly reactive molecules called free radicals damage sperm quality and body tissues and accelerate aging.
Allan Pacey, professor of andrology at the University of Manchester, said the study adds to a growing body of research suggesting that men with poor sperm quality have an increased risk of getting sick or dying prematurely.
"So far no one has come up with a satisfactory explanation," he said. "It is possible that ... an unrecognised health problem early in life leads to both worse sperm quality in younger men and poor health in later life.Clearly we need to do further work to unravel this."
He went on to stress that it is important that men with poor sperm quality do not panic, but take the opportunity to discuss any concerns with their fertility specialist or family doctor.
Finally, she said that as men get older, they should be encouraged to take part in any health screening offer that is made to them.
