Occurrence of oral leukoplakia and lichen planus in diabetes mellitus.

The occurrence of oral leukoplakia and lichen planus in 1600 patients with diabetes mellitus (815 type 1: insulin-dependent, 761 type 2: non-insulin-dependent)-under care at the International Medicine Department-was studied. Precancerous lesions and conditions were diagnosed and grouped according to internationally accepted criteria. The prevalence of oral leukoplakia in diabetic patients was 6.2%, as compared to 2.2% in the healthy controls, that of oral lichen was 1.0% in the test-, and 0.0% in the control group. Leukoplakia and lichen both showed the highest occurrence in the second year of established diabetes, and their prevalence was higher among insulin-treated diabetics. Smokers were more often affected, by both kind of lesions, oral lichen showed a more frequent association with candidiasis. The prevalence of oral leukoplakia and lichen in diabetes mellitus patients was higher, than average ratios in population samples from the same country.