CHICAGO – Low testosterone levels alone didn’t account for the finding, said , professor of reproductive endocrinology at the University of Brescia, Italy.
“So at the end, we showed that, independent of testosterone, low sperm count could be a marker of general male health, in particular for cardiovascular risk factors or metabolic derangement,” said Dr. Ferlin in an interview following a press conference at the annual meeting of the Endocrine Society.
The Italian , which Dr. Ferlin said was the largest of its kind to date, studied 5,177 males who were part of an infertile couple, comparing men with low sperm count (less than 39 million sperm per ejaculate) with those with normal sperm count (at least 39 million sperm per ejaculate). In all, 2,583 of the participants had low sperm counts.
“Our main aim was to understand if semen analysis and, in general, the reproductive function of a man, could be a marker of his general cardiovascular and metabolic health,” said Dr. Ferlin.
Only men with a comprehensive work-up were included, so all participants had a medical history and physical exam, and semen analysis and culture. Additional components of the evaluation included blood lipid and glucose metabolism testing, reproductive hormone levels, ultrasound of the testes and, for men diagnosed with hypogonadism, bone densitometry.
The study, said Dr. Ferlin, found that among men with a low total sperm count, there was a high prevalence of hypogonadism, defined as both low testosterone and elevated levels of luteinizing hormone. Additionally, these men had a high prevalence of elevated luteinizing hormones with normal testosterone – “so-called subclinical hypogonadism,” said Dr. Ferlin.
In men with a low sperm count – defined as fewer than 39 million sperm per ejaculate – the prevalence of biochemical hypogonadism was about 45%, compared with just 6% in men with normal sperm counts, said Dr. Ferlin. Men with infertility had an odds ratio for hypogonadism of 12.2, said Dr. Ferlin (95% confidence interval, 10.2-14.6).