Men who are unable to produce sperm are much more likely to develop cancer, new research has revealed.
Men who are diagnosed as azoospermic – infertile because of an absence of sperm – before they are 30 are eight times more likely to develop cancer than the general population, the research has shown.
The cancers that these men developed were not limited to their reproductive organs either - with the risk affecting men's chances of developing stomach cancer and even leukaemia.
Men who are diagnosed as azoospermic - infertile because of an absence of sperm - before they are 30 are eight times more likely to develop cancer that the general population is
Experts at Stanford University School of Medicine found that azoospermic men have about the same cancer risk as would be typical for someone ten years older than they are.
In the U.S., about 15 per cent of men between the ages of 15 and 45 are infertile.
Dr Michael Eisenberg, assistant professor of urology at the medical school, said: ‘There is evidence that infertility may be a barometer for men's overall health.
‘A few studies have found an association of male infertility with testicular cancer.’
However, he added that the new study suggests that the risk extends beyond testicular cancer.
Dr Eisenberg conducted the study using data gathered from the Texas Cancer Registry and the Baylor College of Medicine in Houston.
He looked at 2,238 infertile men who were seen at a Baylor andrology clinic from 1989 to 2009.
Their average age was 35.7 when they were first evaluated for the cause of their infertility. Of those men, 451 had azoospermia, and 1,787 did not.
After undergoing a semen analysis, the men were followed for an average of 6.7 years to see which of them turned up in the Texas Cancer Registry.
Men who are unable to produce sperm have about the same cancer risk as would be typical for someone ten years older than they are
Their rates of diagnosed cancer incidence were then compared with age-adjusted cancer diagnosis statistics for men in Texas in general.
In all, 29 of the 2,238 infertile men developed cancer during the study period.
This contrasted with an expected 16.7 cases – an estimate that was based on the male Texan population as a whole.
This meant that infertile men were 1.7 times as likely to develop cancer as men in the general population. This is considered a moderately increased risk.
However, comparing the cancer risk of azoospermic and non-azoospermic infertile men revealed a major disparity.
Genetic defects that result in azoospermia may also broadly increase a man's vulnerability to cancer
The azoospermic men were at a substantially elevated risk — nearly three times as likely to receive a diagnosis of cancer as men in the overall population.
By excluding men whose cancer diagnosis came within two or three years of their infertility evaluation, the researchers were able to rule out the possibility that azoospermia caused by an undiagnosed cancer had affected the statistics.
While the study wasn't large enough to delineate which specific types of cancer pushed azoospermic men's incidence rates up, the diagnoses they received covered a wide range of cancers - brain, prostate and stomach tumours, as well as melanoma, lymphoma, testicular cancer and cancer of the small intestine.
The findings suggest that the genetic defects that result in azoospermia may also broadly increase a man's vulnerability to cancer, Dr Eisenberg said, supporting the notion that azoospermia and cancer vulnerability may share common genetic causes.
Most striking of all, said Dr Eisenberg, was the cancer risk among azoospermic men who first had their semen analysed before they reached the age of 30.
They were more than eight times more likely to subsequently develop cancer than Texan males of the same age in the general population.
The good news, Dr Eisenberg said, is that while the cancer risk among young azoospermic men was quite large compared to their peers, their relative youth means that their absolute risk of contracting cancer during the follow-up period remained small.
Azoospermia can arise for two reasons. Obstructive azoospermia is caused by a blockage that prevents otherwise plentiful, fit sperm produced in the testes from reaching the ejaculate.
But a screen of about one-fourth of the azoospermic men in the study population indicated that the vast majority suffered from the non-obstructive variety.
This meant their testes didn't produce enough sperm for any to reach their ejaculate, most likely because of genetic deficiencies of one sort or another.
Read more: http://www.dailymail.co.uk/health/article-2345828/Infertile-men-EIGHT-times-likely-cancer-fertile-peers-researchers-claim.html#ixzz2X3qg7Cj6
Follow us: @MailOnline on Twitter | DailyMail on Facebook
