The
latest scientific surveys and studies indicate that sperm count in men of the
developed world, especially North America, Australia, New Zealand and Europe,
have dropped substantially over the years. According to the researchers, in
less than 40 years, collective sperm count among western men has declined more
than 50%. Sperm count is regarded as a major indication of male fertility.
The
new study indicates that men’s sperm counts are on a continued decline. “The results are indeed
very profound, and even shocking,” says researcher Dr. Hagai Levine, head of
the environmental health track at the Hebrew University-Hadassah Braun School
of Public Health and Community Medicine in Jerusalem.
Eventhough
the study is not the first to arrive upon such a finding, the researchers say
it’s the first ever meta-analysis on the subject. The new findings have
limitations—they don't include men from non-Western countries, for one—but the
researchers say the study adds to a growing body of research on how changes in
environments might be affecting male fertility.
“The impact of the modern environment on
health of populations and individuals is clearly huge, but remains largely
unknown." says Dr.Levine
The
researchers screened 7,500 studies and found 185 that met their criteria.
Studies were included in the analysis if they looked at either men who were
unaware of their fertility (for example, men who had never tried to conceive)
or men who were deemed fertile (for instance, men known to have conceived a
pregnancy). They excluded studies with men who had been included for suspected
infertility, such as men attending an IVF clinic.
They
found that from 1973 to 2011, there was a steep decline of more than 50% in
both sperm concentration and total sperm count among men from Western
countries. The researchers also restricted the analysis to studies after 1995
and reported that the decline does not appear to be abating.
“This has been a recognized phenomenon for
over 50 years. This is a serious problem” says Dr. Enrique Schisterman, chief
of the epidemiology branch at the National Institute of Child Health and Human
Development at the the National Institutes of Health and a male fertility
expert. (Schisterman was not involved in the study.)
The
study did not explain why sperm counts might be down in this group of men, but
there are several theories based on prior research performed by the researchers
and other groups. Levine says that drops in sperm counts have, in the past,
been associated with environment and lifestyle factors including prenatal
chemical exposures, adult pesticide exposures, smoking, stress and obesity.
One conclusion that can be arrived upon
through the study is that men residing in Western countries were exposed to new
manmade chemicals during their life course, and there is more and more evidence
that these chemicals hurt their reproductive function. The researchers
expressed their hope that their findings should drive massive scientific effort
to identify the causes and modes of prevention.
Dr.
Schisterman also suspects that environmental factors may be having an impact on
the rapid decline of male fertility and not genetics.
Dr.
Levine points out that the root causes have to be identified. Moreover, every
man can live a healthier life by reducing stress, not smoking, being physically
active and keeping a good diet and weight.”
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