Men with low sperm counts are at higher risk of metabolic disease in later years, according to a study just presented at the European Association of Urology 2016 Congress in Munich, Germany, and recently published in Clinical Endocrinology.
"This study is very interesting, as is the question it poses: whether infertility in men below the age of 50 years might be used as a predictor for development of metabolic diseases, including diabetes and osteoporosis later in life," commented University of Copenhagen Prof Jens Sønksen of the European Association of Urology Scientific Congress Office in a conference statement.
About 15% of all couples experience infertility, and about half the time, this is due to male infertility. Studies have shown a link between men with poor semen quality and a lower life expectancy, but the link is unexplained and no biochemical markers have been discovered.
"There is a significant need for more studies in this field," Dr Sønksen added.
Men With Low Sperm Counts Have 10-Fold Risk of Hypogonadism
First author Johannes Bobjer, MD, of Skåne University Hospital and Lund University in Malmö, Sweden, and colleagues explain that it is not yet known to what degree young subfertile men present with signs of hypogonadism and whether low testosterone concentration, as in older men, is associated with risk of osteoporosis and metabolic derangements in those subjects
To examine this issue, they studied 192 men aged 18 to 50 with a low sperm count (< 20x106/mL) who were attending the Reproductive Medicine Center at Skåne and compared them with an age-matched control group of 199 men.
They compared sex hormone levels and other markers such as bone mineral density (BMD) and HbA1c levels.
The rate of hypogonadism — low testosterone levels — was 10 times higher among the men with fertility problems than among the men in the control group.
One-third of the subfertile men had low testosterone levels, and the latter was associated with higher HbA1c concentration (mean difference, 2.8 mmol/mol; P = .011) and lower lumbar spine BMD (mean difference, 0.05 g/cm2; P = .032) compared with those with normal testosterone levels.
Furthermore, subfertile men with subnormal testosterone concentration presented with higher triglycerides and signs of insulin resistance as well as increased risk of manifest metabolic syndrome compared with subfertile men with testosterone and luteinizing hormone (LH) levels within the normal range.
Researchers say the main strength of the study, in addition to the age-matched control group, is that it includes relatively young subjects with low prevalence of concurrent systemic diseases, which might be the cause and not consequence of low testosterone production.
Check Hormones in Subfertile Men, but Don't Give Testosterone
Senior author Aleksander Giwercman, MD, PhD, of the Reproductive Medicine Center at Skåne University Hospital, told Medscape Medical News that since the findings indicate that a significant proportion of men from infertile couples present with biochemical signs of hypogonadism, "All men with fertility problems and any abnormality in semen quality should have their [reproductive] hormones checked at their first visit."
And given the risk for developing diabetes, those with low testosterone who are obese may want to increase weight-reduction efforts and increase physical activity he said.
But as to whether testosterone treatment is warranted to avoid metabolic disease, he said this isn't a good idea.
Testosterone should be avoided as long as a couple is receiving treatment for infertility, since administration of testosterone may additionally suppress sperm production.
Also, he said, "It remains to be proved that testosterone treatment as such can give a long-term improvement of metabolic parameters and bone mineralization."
Dr Giwercman said his team would like to follow the men in the study to see whether their symptoms worsen without intervention.
What About Older Men?
The link between low testosterone and metabolic disturbances such as metabolic syndrome, type 2 diabetes, cardiovascular disease, and osteoporosis is well established in older men, but the causes are not well understood, and the issue of testosterone treatment is the subject of much controversy.
"Some studies suggested that low testosterone is merely a marker of poor general health in elderly men," the authors write.
Dr Giwercman said physicians may be reluctant to start testosterone therapy in older men because of the uncertainty regarding the risk/benefit profile, but he recommended the treatment if testosterone levels are really low and there are no contraindications against it (eg, prostate cancer).
"Overt metabolic or cardiovascular problems should be treated according to existing guidelines," he concluded.
The study was supported by the Swedish Research Council, Skåne University Hospital Foundation, and the Swedish government. The authors declared no relevant financial relationships.
Clin Endocrinol. Published online February 29, 2016. Abstract
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Cite this: Infertile Men Have Higher Risk of Diabetes, Osteoporosis - Medscape - Mar 16, 2016.