Researchers at Queens University, Belfast, have found that sperm from diabetic men shows more DNA damage than the sperm from men without diabetes.
It was the first time medical researchers had compared the sperm of healthy men with those who had diabetes and their findings suggest that men with diabetes may experience problems with their fertility.
Of 27 diabetic men who had their sperm samples examined, semen volume was significantly less than in samples from healthy men. Although the sperm looked normal, when it was measured for DNA damage it was found to have greater levels of fragmentation and more deletions in DNA – in the mitochondria, or energy generating structures in the cells.
Diabetes May Cause Infertility
Queen’s research fellow, Dr Ishola Agbaje, 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 incidence of type one and type two diabetes is increasing rapidly worldwide. Type two diabetes (late onset) is usually related to poor diet and obesity. Type one diabetes is usually diagnosed in childhood or in the teen years and the number of European children with type one diabetes is increasing by 3% every year. The reason is unclear, but scientists think that a combination of factors may be at play, such as genes and environmental factors like exposure to viruses.
Because there is such a large and growing community of people affected by diabetes, this could potentially cause a substantial number of male factor infertility cases.
Dr. Agbaje added, “One in six couples require specialist investigation to conceive. The last 50 years have seen a decline in semen quality. Sperm disorders may cause or contribute to infertility in 40-50% of infertile couples. The increasing incidence of systemic diseases like diabetes may further exacerbate this decline in male fertility.”
Professor Sheena Lewis, of Queen’s Reproductive Medicine Research Group, said: “Our study shows increased levels of DNA damage in sperm from diabetic men. From a clinical perspective this is important, given the growing body of evidence that sperm DNA damage can impair male fertility and even the health of future generations.”
Fragmented sperm can cause failure to implant, failure of the embryo to develop, early miscarriage or even failure to get pregnant in the first place.
Further studies with men who have diabetes are being planned to determine whether DNA damage caused by diabetes has the same detrimental affect on fertility that DNA damage caused by smoking does.
Source: Insulin Dependent Diabetes Mellitus: Implications for Male Reproductive Function. Human Reproduction, 3rd May 2007.