Purpose: Results from studies of smoking and non-Hodgkin lymphoid neoplasms (NHL) are inconsistent. This study assessed whether this inconsistency might be due to the heterogeneous nature of the disease, to different relationships in subpopulations such as gender, or to chance.
Methods: We examined cigarette smoking status, initiation, intensity, and duration in relation to the risk of NHL, and subtypes of NHL in men and women from the American Cancer Society Cancer Prevention Study II Nutrition Cohort. From 1992 to 2007, 1,926 NHL cases were identified among 152,958 subjects. Extended Cox regression was used to compute multivariable rate ratios (RR) and 95 % confidence intervals (95 % CI).
Results: The RR (95 % CI) for current smoking associated with NHL incidence in women was 1.37 (1.04-1.81) and in men was 0.88 (0.65-1.19). Among current smokers, there was a positive relationship between years smoked and risk of NHL in women (p-trend < 0.01), but no association in men. In women, the positive associations with current smoking were strongest for follicular lymphoma (RR 2.13, 95 % CI 1.20-3.77) and chronic lymphocytic leukemia/small lymphocyte lymphoma (RR 1.75, 95 % CI 1.03-2.96). In men and women combined, current smoking was associated with an increased risk of T-cell lymphoma and a decreased risk of diffuse large B-cell lymphoma.
Conclusions: This study supports an association of current smoking with risk of NHL that varies by gender and subtype. Future studies should focus on differences by gender and disease subtype to better clarify the smoking and NHL relationship.