Lung cancer risk and cigarette smoking, lung tuberculosis according to histologic type and gender in a population based case-control study

We examined whether the strength of the association of cigarette smoking differs according to histological type and gender, and assessed other risk factors, in particular, tuberculosis. We recruited cases from the Korean Academy of Tuberculosis and Respiratory Diseases and controls from Chungju, a local site of the Korean Multi-Center Cancer Cohort. We matched one case to one control for females and two cases to one control for males according to age (≤44, 45-69, and ≥70 years old). We used unconditional logistic regression to calculate the odds ratio (OR) and 95% confidence interval (CI) to estimate lung cancer risk by histologic type for males and females separately. The OR (95% CI) of 40 or more pack-years smoked relative to never smokers was 6.78 (4.17-11.00), 3.49 (1.83-6.33), and 2.72 (1.57-4.72) for males, and 13.72 (3.23-58.18), 12.18 (3.12-47.57), and 7.11 (1.78-28.43) for females for squamous cell, adenocarcinoma, and small cell carcinoma, respectively. Among males, the respective OR (95% CI) for past and current history of lung tuberculosis was 3.21 (2.12-4.90), 2.69 (1.63-4.45), and 1.52 (0.83-2.78), and for females was 2.40 (1.30-4.42), 4.20 (2.75-6.39), and 1.37 (0.61-3.06). Our findings provide additional evidence that women are more susceptible to the carcinogenic effects of tobacco, smoking has a higher risk for squamous cell and small cell carcinoma than adenocarcinoma, and tuberculosis is a potential risk factor for certain lung cancer histologic types.