New Danish research shows that men with reduced semen quality are not more likely to develop osteoporosis, as potentially feared.
Every year, thousands of Danish couples need assisted reproduction to have a child. A common reason for this is poor semen quality (including both the quantity and quality of the sperm), necessitating assisted reproduction.
Previous research has shown that men with reduced semen quality die on average earlier than fertile men, and osteoporosis has been a potential cause.
But the new study concludes that men with unexplained infertility for no obvious reason have the same bone mineral density as fertile men.
“When we determine that a man is infertile, we always check whether this may be caused by illness or perhaps very low testosterone. If not, we send him and his partner to a fertility clinic so they can get help in making the child they dream of. Our new results reassure us because they show that men’s infertility has not yet affected their bone mineral density, so we do not need to do anything else,” explains the researcher behind the new study, Niels Jørgensen, specialist in endocrinology, Department of Growth and Reproduction, Julian Marie Centre, Rigshospitalet, Copenhagen.
The research results were recently published in Andrology.
Infertile men die earlier than fertile men
The background for the new study is research from 2009, in which Niels Jørgensen’s colleagues found that infertile men had excess mortality.
The study, which examined the semen quality of 43,000 Danish men from 1963 to 2001, found that semen quality was associated with mortality.
However, the research did not show why men had a greater risk of dying, and Niels Jørgensen’s new research is just one of many attempts to answer this question.
“People do not die from poor semen quality, so this must be a marker for something else negative. Nor are men with poor semen quality mostly in one specific social group, so something else must increase the mortality of these apparently healthy but infertile men. Nevertheless, we have not yet identified what makes them sick or die earlier,” says Niels Jørgensen.
Examined bone mineral density among 143 infertile men
Low testosterone levels may be the reason for and the possible link between infertility and osteoporosis, which may cause premature death.
When boys reach puberty late, they tend not to reach peak bone mineral density, and low testosterone levels can also lead to reduced sperm production.
Infertile men are normally examined for low levels of testosterone because the levels are clearly linked with fertility and treatment is required. However, the new study investigated whether slightly lower testosterone levels that might not otherwise cause concern could also be linked to osteoporosis.
To investigate whether osteoporosis is generally associated with infertility, Niels Jørgensen and his colleagues conducted a small study using dual X-ray absorptiometry (DXA) to determine the bone mineral density of 143 infertile men and a similar group of men who had just made their partner pregnant.
The results were unequivocal.
“We obtained good results: no difference in bone mineral density at this stage of life, with the average age of our study group being 34 years. In other words, we do not have to worry about the bone mineral density of men who are both infertile and do not have low levels of testosterone,” says Niels Jørgensen.
Major study to find the causes of death among infertile men
The researchers’ next step is to investigate the status of the men later in life and Niels Jørgensen has started analysing data for men who were treated for infertility 10–15 years ago.
These men are being followed up so that researchers can determine whether infertility is associated with reduced bone mineral density among men when they become 45–50 years old.
The research group is also carrying out a very large registry study with 80,000 Danish men who have been examined for infertility.
This major study will link data from fertility studies with health records so that researchers can get an overview of the possible causes of premature death among infertile men.
“We have to sift through a lot of health data to determine whether infertile men have specific diseases and whether these diseases are associated with poor semen quality. However, some groups of men may have specific genetics or specific profiles that increase their risk of infertility. The goal is to be able to inform men with fertility problems at some point whether they have increased risk for various diseases. We may then also be able to prevent a disease or a potential premature death by using medicine or by getting these men to change their lifestyles,” says Niels Jørgensen.
“Bone mineral density is preserved in men with idiopathic infertility” has been published in Andrology. In 2013, the Novo Nordisk Foundation awarded a grant to Niels Jørgensen for the project Is Male Infertility a Risk Factor for Later Occurring Morbidity?