Does the time of diagnosis of Type 2 diabetes have a seasonal variation?

This prospective, observational study from 1987 to 1990 inclusive, set in hospital diabetes clinics in Leicester City, England (population 287,000), sought to establish whether or not Type 2 diabetes has a seasonal variation in incidence. The dates of diagnosis of 833 newly diagnosed Type 2 diabetic patients were recorded and total monthly incidence over the four year period calculated. Seasonal incidence was assessed by the Edward's test and the test for uniformity on a circle. No seasonal variation in the incidence of Type 2 diabetes was demonstrated, X²=4.32, p=0.11 and X²=3.32, p=0.19 respectively. These findings suggest that, unlike Type 1 diabetes, seasonality plays no significant role in the presentation of Type 2 diabetes. No increase in health care provision is required to cope with seasonal variation in Type 2, unlike that for Type 1 diabetes.