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4 hours ago
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Sperm may be the canaries in the coalmine for male health, according to research that reveals men with higher-quality semen live longer.
Danish scientists analysed samples from nearly 80,000 men and found that those who produced more than 120 million swimming sperm per ejaculate lived two to three years longer than those who produced fewer than 5 million.
The men with the highest-quality sperm lived to 80.3 years old on average, compared with 77.6 for those with the poorest-quality sperm, the researchers report in Human Reproduction.
“It really seems to be that the better the semen quality, the longer the survival,” said Dr Lærke Priskorn, an epidemiologist at Copenhagen university hospital, who led the study with Dr Niels Jørgensen, an andrologist at the hospital.
The finding implies that semen quality reflects a man’s broader health and how likely he is to succumb to medical conditions later in life. On every measure of sperm quality the researchers checked, poorer quality was linked to earlier death.
The men in the study had their semen analysed between 1965 and 2015 after they reported problems starting a family with their partner. The samples were assessed for semen volume, sperm concentration, sperm shape, and the proportion of motile, or swimming, sperm. While some men produced no sperm, others had very good semen quality.
Using national registers, the researchers tracked the men’s health for up to 50 years after their sperm tests. There were 8,600 deaths in the follow-up period, amounting to 11% of the group. Nearly 60,000 of the men provided semen samples between 1987 and 2015 and their records held more information, such as education level and any medical conditions diagnosed in the 10 years prior to the semen analysis.
The link between poor semen quality and an earlier death was not explained by any diseases diagnosed in the decade before testing, nor by the men’s education level, which often reflects socioeconomic status and to some extent lifestyle factors such as smoking, diet or exercise.
Priskorn said that while the data did not shed light on the potential biological mechanisms, conditions in the womb may be important. In this scenario, factors that affect the baby’s development would harm both their sperm and wider health in later life.
The researchers now want to find out which diseases are more common in men with poor semen quality. If particular conditions are identified, doctors could ultimately advise men on preventive action should sperm analysis show they are at risk.
In an accompanying editorial, Prof John Aitken, a reproductive biologist at the University of Newcastle in Australia, said: “If spermatozoa really are the canaries in the coalmine of male health, the obvious question to ask is why.”
Possible drivers are genetic defects on the sex chromosomes, an impaired immune system, coexisting problems such as heart disease, lifestyle factors, and pollutants. Aitken suspects a process called oxidative stress, where highly reactive molecules called free radicals harm semen quality and body tissues and accelerate ageing.
Allan Pacey, a professor of andrology at the University of Manchester, said the study added to a growing body of work suggesting that men with poor semen quality had an increased risk of ill-health or dying early.
“So far no one has come up with a satisfactory explanation,” he said. “It’s possible that … an unidentified health issue early in life both leads to poorer semen quality in younger men and ill health in later life. We clearly need to do further work to unravel this.
“It’s important that men with poor sperm quality do not panic, but they should take the opportunity to discuss any concerns with their fertility specialist or family doctor. As they get older they should be encouraged to engage with any offer of any healthcare screening which is offered to them.”
