Changes in glucose tolerance during three years' follow-up in an elderly population

The aim of this study was to describe changes in glucose tolerance over 3 y and to establish the prevalence of diabetes and impaired glucose tolerance in an unselected non-institutionalised elderly population aged 70 y or over at the beginning of the study. Diabetes was assessed on the basis of self-reports and 2 h oral glucose tolerance tests which were classified according to the 1985 WHO criteria. At the end of the follow-up period, 15% (n=14) of the men were diagnosed as having previously diagnosed diabetes, 8% (n=7) as having previously undiagnosed diabetes, 36% (n=33) as having IGT and the remaining 41% (n=38) as having normal glucose tolerance. The corresponding figures for the women were: 22% (n=37), 8% (n=13), 37% (n=61) and 34% (n=56), respectively. More than one third of the people with baseline normal glucose tolerance (NGT) had progressed to impaired glucose tolerance (IGT) or diabetes mellitus (DM) (n=44). Almost one third of those with baseline IGT had reverted to NGT (n=24), half had persisting IGT (n=41) and one fifth had progressed to DM (n=14). Almost one fifth of the subjects with baseline DM had reverted to IGT (n=12), and only one had reverted to NGT. In conclusion, a comparatively high proportion of both previously diagnosed diabetes, previously undiagnosed diabetes and IGT were found in the follow-up examinations of this elderly study population. The rate of deterioration of glucose tolerance during 3 y follow-up was also moderately high among these elderly subjects.