Smoking and alcohol and subsequent risk of myelodysplastic syndromes in Japan: the Japan Public Health Centre-based Prospective Study.

Smoking and alcohol are important modifiable risk factors for human cancers. However, few epidemiological studies have investigated their association with the risk of myelodysplastic syndromes (MDS). Here, we investigated the association of smoking and alcohol consumption and the risk of MDS in a large-scale population-based cohort study in Japan. We included 95 510 Japanese subjects (45 451 men and 50 059 women; age 40-69 years at baseline) and identified 70 MDS cases (50 men and 20 women) during 18·3 years of follow-up. Hazard ratios (HRs) and 95% confidence intervals (95% CI) were estimated using a Cox regression model adjusted for potential confounders. Smoking was marginally associated with an increased risk of MDS among men, with a HR for current smokers relative to never smokers of 2·11 (95% CI: 0·91-4·89). In contrast, alcohol consumption was associated with a dose-dependent decrease in the risk of MDS among men (nondrinkers: reference, occasional drinkers: HR = 0·48, 0·16-1·41; 0-299 g/week: HR = 0·37, 0·19-0·73; ≥300 g/week: HR = 0·49, 0·22-1·08, P for trend = 0·010). This study showed that alcohol has a significant protective effect on the risk of MDS. In addition, this study might indicate that smoking increases the risk of MDS among Japanese population, as it does in Western populations.