In this week's BMJ, two studies by Eborall and colleagues assess the psychological impact of screening for diabetes mellitus in primary care.1 2 Screening for diabetes is primarily aimed at preventing cardiovascular disease. The risk of cardiovascular disease increases proportionally as concentrations of glucose increase, with no threshold below which the risk remains constant.3 This is in contrast with other complications of diabetes—such as retinopathy, neuropathy, and nephropathy—the risk of which sharply increases when glucose concentrations exceed the threshold of 11 mmol/l. At this concentration the typical diagnostic signs of diabetes are usually present—thirst, polyuria, and weight loss.

Population based mass screening for diabetes has been proposed for several years.4 This has been fuelled by rising plasma glucose concentrations in most populations worldwide, as a result of increasing body weight associated with a more sedentary lifestyle and changes in diet. Arguments for mass screening include the fact that …