Infertile men have an increased risk of metabolic diseases as they age, according to a new study.

A team of Swedish researchers recruited 192 male participants from the Reproductive Medicine Center at Skåne University Hospital, Malmö, who had low sperm count. The researchers measured their sex hormone levels, bone mineral density and HbA1c, which is a biomarker for diabetes, and compared these measurements to a control group of 199 men. The participants were between the ages of 18 and 50.

The team found that men with fertility problems were seven times more likely than men in the control group to have low sex hormone levels (hypogonadism). Men from the low sperm count group also had low bone density, higher levels of HbA1c and more evidence of insulin resistance.

The researchers reported that hypogonadism could be tied to an increased risk for these factors, which contribute to the men's risk of metabolic disease, diabetes, fractures and osteoporosis.

"We found that a significant proportion of men from infertile couples show biochemical signs of hypogonadism," lead study author Aleksander Giwercman said. "This may be affecting their fertility, but they can also serve as early warning signs for metabolic diseases in later life, such as osteoporosis or diabetes. We would recommend that levels of reproductive hormones should be checked in all men seeking advice for fertility problems. Those at risk of serious disease should be followed after the completion of fertility treatment. "

Although the study did not find a causal relationship, the researchers noted that their findings could explain why men with semen quality issues tend to have a shorter life expectancy in comparison to men who have normal semen.

"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. There is a significant need for more studies in this field," said professor Jens Sønksen of the European Association of Urology Scientific Congress Office, who was not involved with the research.

The study was presented at the European Association of Urology conference and published in the Feb. 29 issue of the journal Clinical Endocrinology.