All right, it's all over the news today, so men all over the
world are wondering if they should father children if they have diabetes. So,
let's break this down and interpret it. Scientists have found that sperm from
type 1 diabetic men have greater levels of DNA damage than sperm from men who
do not have the disease. They warn that such DNA damage might affect a man's
fertility.
Researchers from Belfast, Northern Ireland showed that the
DNA in the nuclei of the sperm cells had greater levels of fragmentation in
diabetic men (52%, versus 32% in non-diabetic men), and that there were more
deletions of DNA that would affect the tiny, energy-generating structures in
the cells called mitochondria (4 versus 3).
First of all, this is the first study to explore this issue.
Second, it involved 27 men with diabetes - not a large number. Not large enough
in My Diabetes Information's opinion to get all uptight about. Third, DNA
fragments all of the time. It can be a big deal. However, the DNA from a sperm
cell is often repaired during conception as it shares DNA from an egg cell. So,
there are about 30,000 genes that they can sort through and figure out what
this means to men with diabetes. It will be a while.
Dr. Ishola Agbaje, who undertook the research published
online this week in the journal Human Reproduction, said, "As far as we
know, this is the first report of the quality of DNA in the nucleus and
mitochondria of sperm in diabetes. Our study identifies important evidence of
increased DNA fragmentation of nuclear DNA and mitochondrial DNA deletions in
sperm from diabetic men. These findings cause concern, as they may have
implications for fertility."
The truth is that they could have implications for more than
just fertility. This is such a new finding from such a small study that it is
very early to speculate about what it might mean. What Dr. Agbaje should do is
try to find a colleague who can replicate the study with a larger group of
patients. The group definitely needs to be composed of at least 30 men with
diabetes. It would be even more helpful to involve more than 60 men with
diabetes.
Professor Sheena Lewis of Queen's Reproductive Medicine
Research Group was one of the researchers involved in the study. Her comments
provided a better interpretation of what this might all mean when she said,
"Our study shows increased levels of sperm DNA damage in diabetic men.
From a clinical perspective this is important, particularly given the
overwhelming evidence that sperm DNA damage impairs male fertility and
reproductive health. Other studies have already shown that, while the female
egg has a limited ability to repair damaged sperm DNA, fragmentation beyond
this threshold may result in increased rates of embryonic failure and pregnancy
loss. In the context of spontaneous conception, sperm DNA quality has been
found to be poorer in couples with a history of miscarriages."
However, Lewis said that it was not possible to say from
this current study whether the DNA damage caused by diabetes would have the
same effect on men's fertility and the health of future children as DNA damage
caused by other factors such as smoking.
"This is just one, relatively small study
that highlights a possible concern," she said. "Further studies need
to be carried out in order to understand the precise nature of the
diabetes-related damage, the causal mechanisms and the clinical significance.
Given the global rise in the prevalence of diabetes, it is also vital to
examine the reproductive outcomes of pregnancies fathered by diabetic men, and
the prevalence of diabetes amongst men attending for infertility
treatment."
