Leukoplakia, lichen planus, and other oral keratoses in 23,616 white Americans over the age of 35 years.

This investigation provides the first detailed population-based reporting of white keratotic lesions of the oral mucosa in a United States population. More than 21% of 3,783 oral mucosal and connective tissue lesions reported from 23,616 white Americans, usually over 35 years of age, were keratotic lesions, representing 3.4% of the entire group of examinees. Leukoplakia was the most common of all lesions diagnosed and was the most common of the keratotic lesions (85.5% of the latter). The prevalence rate for leukoplakia was 28.9/1,000 white Americans over 35 years of age and was twice as high for males as for females (43.2/1,000 males versus 20.9/1,000 females). Age-specific leukoplakia prevalence rates demonstrated a tenfold increase for males from the third to the eighth decade of life, and twofold increase for females from the fourth to the seventh decade. Sites of leukoplakia involvement, in decreasing order of frequency, were lip vermillion, buccal mucosa, mandibular gingiva, tongue, oral floor, hard palate, maxillary gingiva, lip mucosa, and soft palate. Almost 7% of leukoplakias demonstrated carcinoma or severe dysplasia microscopically. Prevalence rates for other white oral mucosal lesions were tobacco/snuff pouch keratosis, 1.6/1,000; chronic cheek bite, 1.2/1,000; lichen planus, 1.1/1,000; palatitis nicotina, 0.7/1,000; and leukoedema, 0.3/1,000.