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06 December 2012

Decline in French Sperm Count Should Be Considered Global Warning

A study, published in the journal Human Reproduction, revealing a significant decline in sperm concentration among French men should be considered a health warning, and could be linked to environmental factors, say its authors. Regarding environmental factors, an article in the Tribune de Genève about the study stated: “Studies have mentioned a correlation with smoking, the consumption of saturated fats or even the use of Wi-Fi!” Perhaps Geneva is waking up!  Read the next post.
Decline in French sperm count should be considered global warning 
by Liat Clark, wired.co.uk, 5 December 2012

A study revealing a significant decline in sperm concentration among French men should be considered a health warning, and could be linked to environmental factors, say its authors.

The paper, published in the journal Human Reproduction, calculated the results after comparing 26,600 samples from France's national register on in vitro fertilisation. The samples, derived from 126 assisted reproduction technology (ART) centres in France, covered the period 1989 to 2005 and were all from men whose partners had chosen in vitro because their fallopian tubes were blocked or missing -- the man's sperm was not considered an issue in any of these cases. This latter point is important because many male fertility studies have, over the years, solely analysed men with pre-existing fertility problems; this study should therefore be a truer representation of the wider population.

The results showed an annual decrease in semen concentration of 1.9 percent, with an overall drop of 32.2 percent. This equates to a drop from 73.6 million sperm cells per millilitre in 1989 to 49.9 in 2005 in 35-year-olds. This still falls within "fertile" realms, according to World Health Organisation guidelines, concedes the study's author Joëlle Le Moal, an environmental health epidemiologist at the Institut de Veille Sanitaire. However, the figure is still an average, so other samples were well below this range and the 49.9 figure is considerably lower than the 55-million-per-millimetre point at which reproduction is considered more difficult.

The team also found there was a 33.4 percent decrease in the percentage of normally-formed sperm, and a slight improvement in sperm motility.

"To our knowledge, it is the first study concluding a severe and general decrease in sperm concentration and morphology at the scale of a whole country over a substantial period," reads the paper. "This constitutes a serious public health warning. The link with the environment particularly needs to be determined."

Despite this bold statement, there has been some controversy surrounding male fertility studies in the past, so the results may need be tempered a little. It's been argued, for instance, that methods of measuring "normal" sperm have changed over the years and may differ from centre to centre. The same goes for measuring concentration. Speaking to the Guardian, Jens Peter Bonde, a professor of occupational medicine at Copenhagen University, points to a 1995 French study that found average sperm counts to be 89 million per millilitre in 1973 and 60 million in 1992 -- the most recent study records far higher numbers.

"Sperm counting is difficult," Bonde told the Guardian. "This conflicting data illustrates the problems with comparing sperm counting across centres without strict control of counting methods. Unfortunately, I don't think this new study helps much to settle the ongoing controversy."

Le Moal and her colleagues, however, argue that the figures represent an overwhelming trend that cannot be ignored. Furthermore, though it was impossible to account for socioeconomic factors that could have contributed to the decline -- such as smoking and weight -- the team argues that in France those who seek out in vitro treatments tend to be well-educated and consequently less likely to smoke and be overweight. That is of course a broad statement in itself, and calculations derived from this assumption that "sperm parameters in the general population could be slightly lower" should be taken with a pinch of salt. Le Moal and his team did, however, take things like age and seasons into account (factors that cause sperm count to fluctuate).

Whether or not the figures are 100 percent accurate, it's hard to ignore the sharp decline that appears to be ongoing. Particularly, says Le Moal, if chemicals that affect the body's hormones such as endocrine disruptors are to blame. If they are, it could lead to irreversible changes in how an individual's genes and cells function, which could then be inherited by their offspring.

"In the UK this issue has never been viewed as any sort of health priority, perhaps because of doubts as to whether falling sperm counts was real," commented Richard Sharpe of Edinburgh's Medical Research Council, not involved in the study. "Now, there can be little doubt that it is real, so it is a time for action.

"Armed with such knowledge, we can potentially prevent or reverse the adverse changes in sperm counts. Without it, we have to expect that sperm counts will continue to decrease. Doing nothing will ensure that couple fertility and average family size will decline below even its present low level and place ever greater strains on society."

Until recently one type of endocrine disruptor, Bisphenol A, was commonly found in plastic bottles including the type used for feeding infants. It has since been banned by the EU, US and Canada, but only as recently as 2010. It's understandable, then, that the French team feel the need to issue a public warning and, as Le Moal says, "help health authorities to reinforce their actions on endocrine disruptors".

Le Moal and her team plan to launch a nationwide monitoring system through the Biomedicine Agency and have called for an international monitoring system.   

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