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The alteration of male reproductive health is linked to lifestyle or environmental changes, including increasing exposure to endocrine disruptors, according to a study by Public Health France.
The deterioration of sperm quality and cases of early puberty probably have environmental causes, but they are difficult to disentangle, said Tuesday Public Health France. The health agency looks in its weekly epidemiological bulletin (BEH) on this "global indicator of public health" that is sperm.
The trend observed by the agency is worrying. Between 1989 and 2005, the sperm concentration dropped by almost one-third (-32.2%), or nearly 2% per year, according to measurements made on nearly 27,000 men consulting with their partner center procreation medical badistance (MPA). "It is possible that this decline began in the 1970s if we take into account a previous study conducted in the Paris region from 1973 to 1992," further stressed the researchers.
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For Prof. Bernard Jégou, director of the Institute for Research in Health, Environment and Work (Rennes), these results are to be qualified. "There are geographical differences that need to be taken into account. We can not say today that this decline is homogeneous throughout the territory, "explains Figaro the specialist.
Professor Patrick Fénichel, head of the department of diabetology, endocrinology and reproductive medicine at the University Hospital of Nice, points to another limit: the profile of the men studied. "The researchers relied on data collected from men consulting an MPA center because their couple can not have children. They do not represent the general population, "he says.
A trend found all over the world
Nevertheless, like the report of Public Health France, it emphasizes that this trend is global. "The phenomenon is so well known that WHO has changed the normal sperm count. It has gone from 20 to 15 million sperm per ml of semen, "he says.
"Various causal hypotheses can be evoked, including exposure to PE" (endocrine disruptors), argue the authors. "Other causes are possible or may be intricate with previous ones, such as smoking in pregnant women (…), nutritional or metabolic factors, air pollution or lifestyle changes (sedentary lifestyle, stress, heat , sleep), "they add.
Rising birth defects
At the same time, the authors of this report note that cases of cryptorchidism (non descent of the testicle) are on the rise in France. The same phenomenon would be found in Korea, United Kingdom and Denmark. "During the fetal life, during a very short window of time, exposure to hormonal factors or testosterone deficiency may result in testes not falling. Cryptorchidism is known to be the leading risk factor for male infertility, and is badociated with an increased risk of testicular cancer, "said Professor Jégou. The number of testicular cancer is also rising, according to this research.
Public Health France researchers point out that experimental studies in animals have shown that this "insufficient hormonal impregnation in androgen" could depend on endocrine disruption. A hypothesis fueled by discoveries made by Pr Fénichel's team.
For 3 years, doctors followed more than 6,000 boys born in the maternity hospital of Nice University Hospital. About 2% of them developed this malformation. "The umbilical cord blood test showed that some endocrine disruptors were more prevalent in mothers who gave birth to boys with cryptorchidism than other mothers," says the reproductive specialist. However, further work is needed to demonstrate a causal link with these substances.
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