Diabetes and gender

It is often assumed that there is little or no sex bias within either Type I (insulin-dependent) or Type II (non-insulin-dependent) diabetes mellitus. This review considers evidence that sex effects of interest and importance are present in both forms of the disease. Type I diabetes is the only majo r organ-specific autoimmune disorder not to show a strong female bias. The overall sex ratio is roughly equal in children diagnosed under the age of 1 5 but while populations with the highest incidence all show male excess, th e lowest risk populations studied, mostly of non-European origin, character istically show a female bias. In contrast, male excess is a consistent find ing in populations of European origin aged 15-40 years, with an approximate 3:2 male:female ratio. This ratio has remained constant in young adults ov er two, or three generations in some populations. Further, fathers with Typ e I diabetes are more likely than affected mothers to transmit the conditio n to their offspring. Women of childbearing age are therefore less likely t o develop Type I diabetes, and - should this occur are less likely to trans mit it to their offspring. Type II diabetes showed a pronounced female exce ss in the first half of the last century but is now equally prevalent among men and women in most populations, with some evidence of male preponderanc e in early middle age. Men seem more susceptible than women to the conseque nces of indolence and obesity, possibly due to differences in insulin sensi tivity and regional fat deposition. Women are, however, more likely to tran smit Type II diabetes to their offspring. Understanding these experiments o f nature might suggest ways of influencing the early course of both forms o f the disease.