title: Smoking and tuberculosis among silicotic patients.
abstract: The aim of the present study was to investigate the relationship between smoking and tuberculosis (TB) among high-risk silicotic patients in Hong Kong. A cohort of 435 silicotic patients tuberculin tested from 1995-2002 was prospectively followed-up until the end of 2005. Baseline characteristics were analysed with respect to positive tuberculin reaction (> or =10 mm) at baseline and subsequent development of TB. Smoking, alcohol use and body mass index were independent predictors of positive tuberculin reaction at baseline in multiple logistic regression analysis. Total cigarette pack-yrs did not demonstrate any significant effect. The annual incidences of TB were 1,841, 2,294 and 4,181 per 100,000 for never-, ex- and current smokers, respectively. On Cox proportional hazard analysis, current smokers have a significantly higher risk of TB than other silicotic patients (adjusted hazard ratio (95% confidence interval (CI)): 1.96 (1.14-3.35)) after controlling for age, alcohol use, tuberculin status, treatment for latent TB infection and other relevant background/disease factors. A significant dose-response relationship was also observed with the daily number of cigarettes currently smoked. Smoking cessation may reduce 32.4% (95% CI: 6.5-54.0) of the risk. Smoking increases the risk of both tuberculosis infection and subsequent development of the disease among silicotic patients.
authors.affiliation: Tuberculosis and Chest Service, Centre for Health Protection, Department of Health, Grantham Hospital, Hong Kong, China. cc_leung@dh.gov.hk
authors.forename: C C
authors.initials: CC
authors.lastname: Leung
authors.forename: W W
authors.initials: WW
authors.lastname: Yew
authors.forename: W S
authors.initials: WS
authors.lastname: Law
authors.forename: C M
authors.initials: CM
authors.lastname: Tam
authors.forename: M
authors.initials: M
authors.lastname: Leung
authors.forename: Y W
authors.initials: YW
authors.lastname: Chung
authors.forename: K W
authors.initials: KW
authors.lastname: Cheung
authors.forename: K W
authors.initials: KW
authors.lastname: Chan
authors.forename: F
authors.initials: F
authors.lastname: Fu
mesh_terms: D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D012829:Silicosis / Q000150:complications* / Q000453:epidemiology / Q000209:etiology; D012907:Smoking / Q000009:adverse effects*; D014376:Tuberculosis / Q000150:complications* / Q000453:epidemiology / Q000209:etiology