Waterpipe tobacco smoking tied to increased cancer mortality risk

Use of waterpipe tobacco (WTP), alone or with cigarettes, contributes to a heightened risk of death from liver, lung, nasopharyngeal, and stomach cancers, according to a study.

For the study, researchers used data from the Hanoi Prospective Cohort Study (HPCS), an ongoing study that involves participants at least 15 years of age in Northern Vietnam. Tobacco smoking and WTP smoking statuses were identified.

The analysis included 39,401 HPCS participants (mean age 40.4 years, 52.3 percent female), with 554 cancer deaths occurring over a median follow-up of 11.01 years. Of the participants, 30,089 were never smokers, 3,079 practiced exclusive WTP smoking, 3,519 practiced exclusive cigarette smoking, and 2,723 practiced dual WTP and cigarette smoking.

Compared with never smokers, smokers were older, tended to be male, had a higher BMI, and were more likely to drink alcohol. Additionally, WTP smokers had lower education levels than never smokers.

Multivariable Cox proportional hazards regression models showed that compared with never smokers, ever smokers had an elevated risk of cancer mortality (hazard ratio [HR], 1.87, 95 percent confidence interval [CI], 1.48–2.35). Exclusive WTP smokers had the highest risk of cancer mortality (HR, 2.66, 95 percent CI, 2.07–3.43), followed by dual smokers of WTP and cigarettes (HR, 2.06, 95 percent CI, 1.53–2.76) and exclusive cigarette smokers (HR, 1.86, 95 percent CI, 1.41–2.45). These associations were more pronounced in males than in females, given that 95.6 percent of smokers were male.

Compared with never smokers, male exclusive WTP smokers were at increased risk of death from liver cancer (HR, 3.92, 95 percent CI, 2.25–6.85), lung cancer (HR, 3.49, 95 percent CI, 2.08–5.88), nasopharyngeal carcinoma (HR, 2.79, 95 percent CI, 1.27–6.12), and stomach cancer (HR, 4.11, 95 percent CI, 2.04-8.27).

In the group of exclusive WTP smokers, the risk of cancer mortality was highest among those who smoked 11–15 sessions per day (HR, 3.42, 95 percent CI, 2.03–5.75), started smoking at age 26 to 30 years (HR, 4.01, 95 percent CI, 2.63–6.11), smoked for 9 to 20 years (HR, 4.04, 95 percent CI, 2.16-7.56), and smoked 61–160 sessions annually (HR, 3.68, 95 percent CI, 2.38–5.71).

Finally, males who had quit smoking for more than 10 years had a lower risk of cancer death than those who quit smoking within 1 year (HR, 0.27, 95 percent CI, 0.11–0.66; p<0.001).

The findings underscore a need for a tailored program to control WTP smoking in Vietnam, as well as in low- and middle-income countries with a high prevalence of smoking and modest resources to address smoking-related issues.