3 May 2007
Diabetes Damages Sperm DNA
by Kate Melville
Diabetic men have greater levels of DNA damage to their sperm, which may affect their fertility and their offspring's future health, say researchers at Queen's University, Belfast.
Comparing the quality of DNA in sperm from diabetic and non-diabetic men, the study found that DNA fragmentation was greater in diabetic men (52 percent, versus 32 percent in non-diabetic men), and that there were more deletions of DNA in the cell mitochondria. Additionally, the researchers observed that semen volume from diabetic men was considerably less than that from men not suffering the disease.
Reporting the findings in the journal Human Reproduction, researcher Ishola Agbaje explained that the findings could have important implications given that the incidence of type 1 and type 2 diabetes is increasing rapidly worldwide. While diet and obesity are known to be key factors in the increase of type 2 diabetes, type 1 diabetes is also increasing, most markedly in European children.
The reasons for the increase in type 1 diabetes are not entirely clear. Other studies speculate that genetic or environmental factors could play a role.
"If the increasing trend in the incidence of type 1 diabetes continues, this will result in a 50 percent increase over the next ten years. As a consequence, diabetes will affect many more men prior to, and during, their reproductive years," said Agbaje. Infertility is already a major concern for health authorities, with up to one-in-six couples requiring specialist treatment in order to conceive. Coupled with the apparent decline in semen quality over the last 50 years, the findings could portend a looming crisis in human reproductive health.
"This [study] 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," said co-researcher Sheena Lewis. "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. It is also vital to examine the reproductive outcomes of pregnancies fathered by diabetic men," she concluded.
Source: European Society for Human Reproduction and Embryology