Novel hazards of waterpipe tobacco and the benefits of stop smoking in men, a prospective cohort study.

Waterpipe smoking is an emerging epidemic and a severe public health problem worldwide. Observational studies on the hazards of a specific new waterpipe tobacco product are timely needed. The objectives were to analyze how dangerous waterpipe tobacco smoking is on the causes of all mortality, including cancer, and how effective smoking cessation is for improving health. We analyzed the hazards of exclusive waterpipe smoking through a prospective cohort study in Northern Vietnam. We obtained exposure data on the smoking status of specific cigarette and waterpipe and smoking cessation histories from each study participant. The outcome includes deaths due to all causes. The cause of death for each case is determined based on medical records. HR (95%CI) was estimated using a Cox proportional-hazards-regression analysis for overall mortality and all cancers. The ever-cigarette smoking group as the reference group, the exclusive waterpipe smoking group had a statistical increase in the risk for overall mortality HR (95% CI): 1.63 (1.32, 2.00), and all cancers HR (95%CI): 1.67 (1.18, 2.38). The risk of death increased statistically in the group of waterpipe smoking over 20 years for overall mortality HR (95%CI): 1.82 (1.45, 2.29), and all cancers HR (95%CI): 1.91 (1.27, 2.88). After stopping smoking, the risk of death decreased steadily. The risk of death was reduced by 41% for overall mortality HR (95%CI): 0.59 (0.39, 0.89), and 74% for death from cancers HR (95%CI): 0.26 (0.08, 0.83) after ten years or longer of cessation. Life expectancy was shortened by more than six years for the group of exclusive waterpipe smokers compared to non-smokers. This study found new novel hazards of exclusive waterpipe tobacco smoking. The findings are scientific evidence for developing strategies, policies, and budget allocations to control this novel tobacco product and promote cessation to improve life expectancy.