Certain
lifestyle factors are linked to higher rates of damage in the genetic material
in men’s sperm, a study suggests. The damage – which may stem from factors like obesity,
stress and even cell phone use – could affect men’s ability to conceive as well
as the genes passed to their children, researchers say.
Semen analysis usually looks at the numbers and the
condition of whole sperm. But the authors of a small study in Poland believe
the degree of breakage, or fragmentation, in DNA strands in the sperm might be
a better indicator of fertility. DNA carries the cell’s genetic information and
hereditary characteristics.
Men with fragmentation have lower odds of conceiving naturally and
through procedures like in vitro fertilization, they write in the International
Journal of Impotence Research.
Researchers have noticed before that lifestyle factors can
influence the level of sperm DNA fragmentation, said Ricardo P. Bertolla of Sao
Paulo Federal University in Brazil, who was not part of the new study.
“More importantly, we do expect that environmental and
lifestyle factors may influence male fertility, but the degree of response is
highly variable among individuals,” Bertolla told Reuters Health by email.
Dr. Marian Radwan of Gameta Hospital in Rzgow, Poland,
focused their study on 286 men under age 45 who were attending an infertility
clinic.
Radwan did not respond to a request for comment.
Most of the men were overweight, nonsmokers, and with moderate levels
of work stress and life stress. Half had been using a cell phone for 6 to 10
years.The men all had normal semen concentrations, but older men and those with higher work stress had more fragmentation of the DNA in their sperm.
Men who were obese or had used a cell phone for more than
10 years also tended to have a higher percentage of immature sperm than others.
Coffee or alcohol use, smoking and physical activity levels
were not linked to DNA fragmentation, the researchers report.
There is some evidence that DNA damage, beyond affecting a
man’s fertility, may be passed along to offspring, raising their risk of gene
mutations linked to various illnesses, the study team notes.
Even men with otherwise normal sperm parameters, like
ejaculate volume and sperm concentration, may have increased levels of free
radicals and DNA damage in their sperm, said Rima Dada of the All India
Institute of Medical Sciences in New Delhi, who was not part of the new study.
Up to 40 percent of reproductive-age men have some issue
with sperm production, Dada told Reuters Health by email.
But they wouldn’t know it, because standard semen analysis
does not involve testing for DNA damage in sperm, she added.
“The important thing is that majority of factors which
cause oxidative stress which result in DNA damage are due to our poor social
habits and unhealthy lifestyle, and simple lifestyle interventions and quitting
smoking and doing yoga and meditation can reduce both psychological stress and
oxidative stress and oxidative DNA damage,” she said.
Bertolla, however, is “currently not convinced” that cell
phone use damages sperm. “I do not see any definitive proof that this is true,”
he said.
The new study does not prove that any lifestyle factors
cause DNA damage in sperm, only that they are associated with each other, he
noted.
“There are some companies that produce antioxidants
specifically designed to improve male fertility, but it is my opinion that
antioxidants are useful only for those men that need it,” he said. “I know this
sounds very simple and obvious, but there are many men that end up taking
antioxidants without a real need for them (or who will not benefit from them),
and this ends up giving a general notion that antioxidant supplementation will
not work.”
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