It was the purpose of this study to report the natural history of glucose tolerance during a five-year follow-up among elderly Finnish men, and to evaluate the role of age and body-mass index in explaining the variation in glucose tolerance both cross-sectionally and longitudinally. In the survivors of the Finnish cohorts of the Seven-Countries Study, aged 65 to 84 years at baseline, a two-hour oral glucose-tolerance test was performed according to current WHO criteria. Subjects with fasting blood glucose > 10 mmol/l were directly classified as having diabetes at baseline.--
Findings: At baseline, of the 637 men 216 had normal and 234 had impaired glucose tolerance, 187 were diabetic. At follow-up, 172 men had died; 38 (18%) of the subjects with normal glucose tolerance at baseline had either impaired glucose tolerance or diabetes; 17 (7%) of the men with initially impaired glucose tolerance had developed diabetes, and 79 (34%) were normalized. 25 (13%) and 22 (12%) of the initially diabetic subjects had reverted to impaired or normal glucose tolerance, respectively. The age was able to explain 1-2% of variation in blood glucose level in cross-sectional but not in longitudinal comparison. Body-mass index was an important predictor of abnormal glucose tolerance in previously normally responding men. By contrast, obesity did not contribute to the development of diabetes among men with impaired glucose tolerance.--
Principal conclusions: The incidence of impaired glucose tolerance was high in these elderly Finnish men as compared with studies in middle-aged Caucasoid subjects.(ABSTRACT TRUNCATED AT 250 WORDS)