Correlation of bronchial epidermoid metaplasia with level of tobacco consumption in heavy smokers.

One hundred forty-four heavy-smoker (125 males, 19 females) volunteers with at least 15 packet-year of smoking experience (number of daily packets of cigarettes X number of years of smoking) underwent bronchoscopy with systematic biopsies in ten sites of the bronchial tree. No morbidity was related to the fibroscopy procedure. Each biopsy was cut into ten sections and an index of metaplasia (IM) was calculated: IM = number of sections with epidermoid metaplasia/number of sections examined X 100. A highly significant statistical correlation was observed (P = 10(-4)) between the IM and the amount of cigarettes smoked (slope of the curve: 0.23). Sex appeared to play an important role in the incidence of metaplasia, since 84% of the examined females had an IM less than 15% versus 48% of the males (P adjusted for individual tobacco consumption in packet-years less than 0.01). Early study of HLA phenotype (locus A) failed to detect a link between HLA and risk of tobacco-induced epidermoid metaplasia.