AIMS

To study the extent and determinants of undiagnosed diabetes mellitus (DM) in Taiwanese subjects with impaired fasting glycemia (IFG) defined by the newly proposed WHO criteria.

METHODS

Oral glucose tolerance tests were carried out for 306 IFG subjects identified from 6632 adult participants of two large scale community-based studies: Nutrition and Health Survey in Taiwan (1993-1996) and the Cardiovascular Disease Two-township Study (1994-1997). Similar protocols were used in these two studies to collect data on glycemic status, anthropometric measurements, and other data used in the present study.

RESULTS

Subjects with IFG had a non-trivial undiagnosed diabetes mellitus rate (30% in men and 42% in women) and a high rate of glucose intolerance and undiagnosed DM combined (75% in men and 86% in women). Women with IFG had a 1.6 fold higher risk (p = 0.04) for undiagnosed DM and a 2.1 fold higher risk (p = 0.01) for glucose intolerance and DM when compared to men. There were more women than men with an elevated body mass index in undiagnosed DM patients. Among IFG subjects, undiagnosed DM patients were significantly (p < 0.05) older, more centrally obese and shorter than their normal IFG counterparts, irrespective of gender. In men, height was independent of age and waist circumference in predicting undiagnosed DM (p = 0.037).

CONCLUSIONS

A high proportion of impaired glucose tolerance and undiagnosed DM was found in subjects with IFG. Its public health impact should not be overlooked. Central obesity, female sex, and short stature were associated with undiagnosed DM status in IFG subjects.