Smoking and drinking have little impact on sperm quality but wearing tight pants does, study finds

An
unhealthy lifestyle may not affect sperm quality as much as previously thought.

A
study in the journal Human Reproduction indicates that smoking, high alcohol
consumption and being overweight have little effect on
semen quality. Wearing tighter underpants, on the other
hand, did reduce levels of swimming sperm, a strong indicator of male
fertility.

Researchers asked
2,249 men at 14 UK fertility clinics to fill in detailed questionnaires about
their lifestyle. They compared the answers of the 939 men with low sperm
quality with the 1,310 men with normal sperm and found that even a 20-a-day
smoking habit did not significantly affect swimming sperm levels.

Study leader Dr
Andrew Povey at the University of Manchester emphasised that lifestyle choices
were 'important for other aspects of our
health' but said that the research 'potentially overturns much of
the current advice given to men about how they might improve their fertility
and suggests that many common lifestyle risks may not be as important as we
previously thought'.

Current advice
from the National Institute for Health and Clinical Excellence
(NICE) suggests doctors should warn men of the negative impact of smoking and
drinking on sperm quality. Fertility treatment is sometimes delayed so couples
can alter their lifestyles.

Dr
Povey said that the study suggested that such a delay 'is unlikely to
improve [couples'] chances of conception and, indeed, might be prejudicial for
couples with little time left to lose'.

A NICE spokesperson told the
BBC that 'the draft update of our fertility guideline is currently open for
consultation. However, until the update of this guideline is published later
this year, the NHS should continue to follow the recommendations in the current
fertility guideline'.

Study
co-author Dr Allan Pacey, from the University of Sheffield, said that lifestyle
factors may affect other aspects of sperm quality - such as the size and shape
of the sperm - not measured in the study. He said it was therefore 'important
that men continue to follow sensible health advice and watch their weight, stop
smoking and drink alcohol within sensible limits. But there is no need for them
to become monks just because they want to be a dad'.

On
the finding that tighter underwear did slightly impact levels of swimming
sperm, he said that if a man trying for a baby was 'a fan of
tight Y-fronts, then switching underpants to something a bit looser for a few
months might be a good idea'.