Men with better semen quality may live longer

Better semen quality is associated with a longer lifespan according to a study in Danish men.

Dr Niels Jørgensen, chief andrologist at Copenhagen University Hospital, Denmark, and his team analysed sperm quality data gathered from 78,284 men. They estimated that men who had a high motile sperm count, representing the number of motile spermatozoa per millilitre of semen, lived two to three years longer than those with a low motile count.

'In absolute terms, men with a total motile count of more than 120 million lived 2.7 years longer than men with a total motile count of between zero and five million,' explained Dr Laerke Priskorn, first author of the study, which was published in Human Reproduction.

Data were gathered from the Danish Semen Quality Database, which contains samples taken between 1965 and 2015 from men who had their semen assessed because of fertility problems. The researchers analysed several parameters of semen quality, including volume, sperm count, motility and shape, and cross-referenced them with data from the Danish national registers, which contained information on the death of those individuals, which had already occurred for 8600 of them. Additional data, including educational background and health conditions during the decade preceding the semen testing, were available for 59,657 men who gave samples after 1986.

Dr Priskorn added: 'This association [with life-expectancy] was not explained by any diseases in the ten years before semen quality assessment or the men's educational level.'

Emeritus Professor John Aitken of the University of Newcastle, Australia, who was not involved in the study, reflected on the findings in a commentary accompanying the paper in Human Reproduction. Professor Aitken suggested that oxidative stress, a state of the body in which there are high levels of damaging molecules called 'free radicals', and not enough antioxidants to neutralise them, causing damage to cells and tissues, could explain the association between sperm quality and lifespan. He wrote: 'Any factor (genetic, immunological, metabolic, environmental or lifestyle) that enhances overall levels of oxidative stress, could reasonably be expected to drive changes in the semen quality profile and subsequent patterns of mortality.'

Future studies could reveal whether semen quality can be used as a predictor of men's general health, or even as an indicator of certain health conditions. 'We need to better understand the association between semen quality and men's general health. This study suggests that we can identify subgroups of men with impaired semen quality who are apparently healthy when their semen quality is assessed, but who are at increased risk of developing certain diseases later in life' said Dr Jørgensen, senior author of the study.

He added: '[Fertility evaluations] would serve as an opportunity for detecting and mitigating the risks of other health problems in the longer term. In the current study, we did not analyse whether poor semen quality was associated with earlier deaths from particular causes, such as cancer or heart disease, and this is something we will be studying in the future.'