Water pipe smoking increases the risk of nasopharyngeal cancer

A Vietnamese cohort study found a clear impact of waterpipe smoking on the development of nasopharyngeal cancer.

The nasopharynx is the part of the pharynx located just behind the nose. Nasopharyngeal cancer is quite rare worldwide, around one case per 100,000 inhabitants, with an incidence rate two to three times higher in men than in women. This type of cancer is particularly prevalent in Asia (85% of cases), notably in southern China and the Canton region, but is also reported in Southeast Asia, North Africa, the Middle East and the Arctic region. In Vietnam, it is the ninth most common cause of cancer, with 6,040 new cases occurring in 2020.

Several risk factors for this cancer have been identified, including being male, of Cantonese ethnicity, carrying the Epstein-Barr virus (EBV) or human leukocyte antigens, having a family history, eating a lot of smoked fish but few fresh vegetables or fruits, and smoking.

With waterpipe tobacco consumption accounting for 30.9% of smokers in Vietnam, a team of Vietnamese researchers attempted to distinguish this risk from that of other smoked tobacco products.[1].

A cohort study conducted over twelve years

The researchers set up a cohort study including 52,325 individuals from nine communes in Northern Vietnam, over a period of twelve years, between 2007 and 2019. After excluding women – who represented only 1.9% of smokers –, children under 10 years old and people who had moved, the study retained 20,144 male participants and analyzed 39 cases of death from nasopharyngeal cancer.

Exclusive cigarette smokers (16.6 %) were distinguished from exclusive waterpipe smokers (14.5 %) and smokers of both products (13.1 %). Ex-smokers were themselves distinguished from people who had never smoked (55.8 %) who constituted the control group. Face-to-face questionnaires assessed tobacco consumption patterns, as well as sociodemographic data, dietary habits, cooking methods and alcohol consumption.

A clear impact of water pipes on the appearance of this cancer

The results show a clear excess mortality from nasopharyngeal cancer among exclusive waterpipe users, and a higher but non-significant risk among dual cigarette and waterpipe users. Having started smoking before the age of 21 was also an aggravating factor, as were the duration of smoking, its intensity and the quantities of tobacco smoked over a lifetime. Exclusive cigarette use, however, seemed to play only a limited role in the onset of this type of cancer. Epstein-Barr virus infection, a major risk factor in the development of nasopharyngeal cancer, could be explained by the sharing of waterpipes, as highlighted by work by the World Health Organization (WHO).[2].

The authors believe that nasopharyngeal cancer is a risk specifically linked to waterpipe smoking, alongside other risks already demonstrated for this type of tobacco consumption: cancers of the mouth, esophagus, bladder, lung, cardiovascular risk and chronic obstructive pulmonary disease (COPD). The concentrations of toxins such as arsenic, chromium or lead in the aerosol of waterpipes would explain, according to them, this toxicity, which is even greater than that of cigarettes, while waterpipes are generally perceived as less toxic by their users.

Keywords: Vietnam, nasopharyngeal cancer, waterpipe, EBV.

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[1] Nguyen, TG, Kieu, HD, Truong, DTT et al. Exclusive waterpipe smoking and the risk of nasopharynx cancer in Vietnamese men, a prospective cohort study. SciRep 13, 13237 (2023). https://doi.org/10.1038/s41598-023-40253-y

[2] Meleigy M, Waterpipe and communicable diseases link, says WHO. Lancet Infect. Say. 7(7), 448. https://doi.org/10.1016/S1473-3099(07)70150-0.