Association of alcohol intake and smoking with malignant lymphoma risk in Japanese: A hospital-based case-control study at Aichi Cancer Center

Given the lower incidence and differences in distribution of malignant lymphoma in Asian than western populations, the association of alcohol intake and smoking with malignant lymphoma risk in Asian populations merits investigation. Here, we conducted a sex- and age-matched case-control study of a Japanese population using two data sets, the first and second versions of the Hospital-based Epidemiological Research Program at Aichi Cancer Center Hospital (HERPACC-I and HERPACC-II, respectively), in 452 and 330 cases of histologically diagnosed malignant lymphoma and 2,260 and 1,650 noncancer controls, respectively. Odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using a conditional logistic regression model that incorporated smoking exposure and alcohol intake. Compared with nondrinking, consumption of ≥50 g/d by frequent drinkers was associated with significantly decreased risk in both data sets [OR (95% CI), 0.70 (0.53-0.93) for HERPACC-I and 0.40 (0.23-0.68) for HERPACC-II]. Given similar findings among groups, we used pooled data sets in subsequent analyses. For any alcohol intake versus nondrinking, point estimates of OR were less than unity for all four malignant lymphoma subtypes. In contrast, pack-years of smoking were associated with increased malignant lymphoma risk: relative to the reference (0-4 pack-years), OR (95% CI) were 1.32 (1.02-1.71), 1.39 (1.07-1.80), and 1.48 (1.12-1.95) for 5 to 19, 20 to 39, and ≥40 pack-years, respectively. This association with smoking was less apparent for all subtypes, except Hodgkin's lymphoma. In conclusion, we found that alcohol had an inverse association with malignant lymphoma risk across all malignant lymphoma subtypes in our Japanese subjects. Smoking appeared to be positively associated with malignant lymphoma risk, but this finding may vary by subtype.