Obesity blamed for male infertility
Europe is facing a male fertility crisis and the rise in obesity could be a primary cause, leading scientists revealed Sunday.
They have found that 40 percent of European men aged 18-25 have sperm counts below that needed to achieve pregnancy easily. Of those, more than half have sperm counts so low that many will be able to have children only through IVF.
A report from the European Science Foundation (ESF) suggested there are several factors contributing to the decline, but rising obesity was among the most important.
This was because men with higher levels of fat seem to produce less testosterone, the hormone whose levels influence many aspects of masculinity, including sperm production.
The report said recent studies had shown “remarkably poor semen quality among young men from general populations in northern Europe.”
It added: “Approximately 20 percent of young men in various European countries had a sperm concentration below the lower WHO [World Health Organization] reference level and 40 percent of the men had a sperm concentration below the level that has been associated with prolongation of the waiting time to pregnancy.”
The ESF represents 79 leading science bodies including British government research organizations such as the Medical Research Council (MRC). Its report brings together the results of 70 original science papers.
It finds correlations between the decline in male fertility and rises in testicular cancer and the number of genital deformities in baby boys, suggesting there could be common factors.
Such trends, also seen in America and other western countries, have been recognized for some time, but the exact causes have eluded doctors.
The latest research suggests, however, that obesity is a clear linking factor. It found that average testosterone levels across all men are lower than in the past and that the decline is proportionately greater for younger and fatter men.
The report said: “Abdominal obesity is clearly associated with reduced testosterone levels and it is also established that obesity is associated with an approximate 20 percent reduction in sperm counts, although it is not clear if it is the obesity that causes the low sperm counts or whether there is an underlying common cause for both.”
In Britain, evidence from MRC researchers and others suggests British men’s average sperm count has fallen from an estimated 113m sperm per milliliter in 1945 to about 62m per milliliter now, a decline of 45 percent. Such dramatic figures have to be treated cautiously because counting methods have changed, but the trend is clear.
The ESF report warns other factors could also be at work, especially exposure to endocrine disruptors - man-made chemicals that interfere with the working of hormones such as testosterone. Potential sources of exposure include food wrapping, cosmetics, pesticides and cigarette smoke. Baby boys exposed through their mothers smoking while pregnant are especially vulnerable.
Earlier this year, an National Health Service study showed that 42 percent of British men are overweight, meaning they have a body mass index greater than 25. About 24 percent of men also count as obese, meaning their body mass index exceeds 30.
In Britain the rise in infertility means about one in six couples needs medical help to conceive. About 14,000 babies - one in 80 - are born through artificial conception.