When a man has no measurable level of sperm in his semen he has azoospermia, he is azoospermic. Fertility experts estimate that approximately 1% of men are azoospermic, and that about 20% of male infertility problems are because of azoospermia.
According to the study, men who are diagnosed with azoospermia before thirty years of age are eight times more likely to develop cancer, compared to other men.
Lead author Michael Eisenberg, MD, PhD, said "An azoospermic man's risk for developing cancer is similar to that for a typical man 10 years older."
Approximately 15% (4 million) of all men aged from 15 to 45 in the USA are infertile. About 600,000 of them are azoospermic - 1% of the male population of the country. The researchers believe that infertility could well be a bellwether for a male's overall health.
While previous studies had linked male infertility to testicular cancer risk, this latest one has found an association between male infertility and other cancers too.
Eisenberg and team gathered and analyzed data from the Baylor College of Medicine in Houston and the Texas Cancer Registry. This included 2,238 men who were seen or treated at a Baylor andrology clinic between 1989 and 2009 - they were all infertile. 451 of them had azoospermia and 1,787 didn't. The authors added that there were no otherwise apparent initial differences between those with and without azoospermia.
Azzospermia has two main causes:
- Obstructive azoospermia - there is a blockage which stops the flow of otherwise plentiful and healthy sperm in the testes from reaching the ejaculate
- Non-obstructive azoospermia - the testes did not produce enough (or any) sperm to reach the ejaculate.
One quarter of all the genes in the human genome play some kind of part in reproduction. This means that there are a huge number of genetic ways a man can be azoospermic.
The men underwent a semen analysis and were followed for 6.7 years (average) to find out how many of them ended up in the Texas Cancer registry. Fortunately for the researchers, most Texans tend to stay in their state long term. The team then compared their incidence of diagnosed cancer with age-adjusted cancer-diagnosis statistics of Texas males overall.
The researchers found that over a 5.8-year period:
- 29 of 2,238 infertile men developed cancer
- 16 fertile men developed cancer, after gathering data for a similar sample-sized population of men of the same age and overall health in Texas. The scientists added that Texas statistics are similar to the rest of the country
- Therefore, infertile men are 1.7 times as likely to develop cancer, compared to the rest of the male population
Large Difference between Azoospermic and Nonazoospermic Infertile MenWhen comparing azoospermic and non-azoospermic infertile males with the general male population, the researchers found that:
- Azoospermic infertile men were 3 times as likely to develop cancer
- Non-azoospermic infertile men were 1.4 times as likely to develop cancer - not a statistically significant difference
The study was not large enough to determine specifically and by how much each cancer rates went up by because of infertility. However, the following cancers developed among those men:
- Brain cancer
- Prostate cancer
- Stomach cancer
- Testicular cancer
- Cancer of the small intestine
Dr. Eisenberg said:
"Most striking of all was the cancer risk among azoospermic men who first had their semen analyzed before age 30. They were more than eight times as likely to subsequently develop cancer than Texas males in the general population of the same age. In contrast, there was no relationship between age of semen analysis and risk of cancer for non-azoospermic men."
Eisenberg said there is good and bad news for young men with azoospermia:
- The good news - although their risk of developing cancer is relatively higher compared to other men of the same age "their relative youth means that their absolute risk of contracting cancer during the follow-up period remained small."
- The bad news - many males in their 30s have no primary health care provider. Eisenberg advises young men diagnosed as azoospermic to be aware of their higher risk of cancer and to have regular check ups.
Household products and medications may raise risk of infertility and cancer - the European Environmental Agency warned that certain foods, drugs, cosmetics and household products contain EDCs (endocrine disrupting chemicals) which have been associated with an increased risk of infertility, obesity, cancer, and diabetes.
Over the last thirty years, the rates of infertility among males, as well as diabetes, breast and prostate cancers have increased considerably. Some scientists believe that this could be partly due to the increasing levels of exposure to mixtures of several chemicals which are in widespread use.
Written by Christian Nordqvist