Insulin dependant diabetes mellitus: implications for male reproductive function.

Background: Diabetes mellitus (DM) is increasing in men of reproductive age. Despite this, the prevalence of diabetes in men attending fertility clinics is largely unknown. Furthermore, studies examining the effects of DM on sperm fertility potential have been limited to conventional semen analysis.

Methods: Conventional semen analysis (semen volume, sperm count, motility and morphology) was performed for 27 diabetic (mean age 34+/-2 years) and 29 non-diabetic subjects (control group, men undergoing routine infertility investigations, mean age 33+/-1 years). Nuclear DNA (nDNA) fragmentation was assessed using the alkaline Comet assay and mitochondrial DNA (mtDNA) deletions by Long-PCR.

Results: Other than a small, but significant, reduction in semen volume in diabetic men (2.6 versus 3.3 ml; P<0.05), conventional semen parameters did not differ significantly from control subjects. Diabetic subjects had significantly higher mean nDNA fragmentation (53 versus 32%; P<0.0001) and median number of mtDNA deletions (4 versus 3; P<0.05) compared with control subjects.

Conclusions: Diabetes is associated with increased sperm nuclear and mtDNA damage that may impair the reproductive capability of these men.