Fasting plasma glucose and subsequent macrovascular disease after 10 yearsfollow-up: a collaborative study on two populations

The American Diabetes Association recently proposed a new, lower, cut-point of 7.0 mmol/l for diagnosis of diabetes mellitus. We examined data from th e Caerphilly and Speedwell cohorts to determine possible cut-points of fast ing plasma glucose for increased risk of subsequent ischaemic heart disease (IHD). Men (n=4860) from the general population of a town in South Wales a nd a practice-based population in Bristol aged 45-63 years were first exami ned in 1979-83, and re-examined at intervals, and these data relate to foll ow-up at about 10 years (120 months, Caerphilly) (112 months, Speedwell). c linically recognized diabetics (n=94) experienced a higher mortality rate a nd an excess number of major IHD events. Among non-diabetics, mean blood gl ucose was 5.0 mmol/l and a significant excess of major IHD events occurred above this point even when the data were fully adjusted for all other IHD r isk factors. Risk of major IHD was greatest for non-diabetic men with plasm a glucose levels between 7.0 and 7.7 mmol/l. Under 7.0 mmol/l, the excess e vent rate was modest, however. Glucose levels were not associated with exce ss all-cause mortality among these non-diabetic men. These data, based on t he excess risk of macrovascular disease experienced by a British cohort of non-diabetic men, accord with the proposals to base the diagnosis of diabet es on a cut point of 7.0 rather than 7.8 mmol/l.