Glucose tolerance and the risk of cardiovascular disease: the Zutphen Study

The impact of glucose tolerance on the incidence of ischemic heart disease (IHD), cerebrovascular disease (CVA), and peripheral arterial disease (PAD) was investigated in the Zutphen Study. In 1970 a complete oral glucose tolerance test (GTT) was carried out on 400 normoglycemic men aged 50-70 yr. A morbidity follow-up was completed in 1985. With GTT classified as the dichotomous variable using the median value of the area under the curve, elevated risks for IHD (RR = 1.6, p < 0.05), fatal IHD (RR = 2.3, p < 0.01), and CVA (RR = 1.9, p < 0.10) were observed, adjusted for potential confounders. No association with PAD was found. Also the risk among non-insulin-dependent diabetics (n = 46) was assessed. These men were clinically diagnosed between 1960 and 1985, median year of diagnosis being 1973, at age 61 yr. Compared with 230 matched non-diabetics increased risks were observed for fatal IHD (p = 0.05), CVA (p = 0.10) as well as PAD (p = 0.05). Thus an elevated risk for IHD, and possibly CVA, may have been found with lower levels of glucose than assumed previously, suggesting a continuous risk gradient. For PAD the relations with glucose tolerance are more complex.