Cigarette smoking and the risk of nasopharyngeal carcinoma: a meta-analysis of epidemiological studies

Abstract

ObjectiveThe role of cigarette smoking as an independent risk factor for patients with nasopharyngeal carcinoma (NPC) is controversial. We attempted to provide evidence of a reliable association between cigarette smoking and the risk of NPC.DesignMeta-analysis.Data sourcesPubMed online and the Cochrane Library of relevant studies published up to February 2016.Eligibility criteriaAll studies had to evaluate the relationship between NPC and cigarette smoking with never smokers as the reference group.OutcomesThe primary outcome was the adjusted OR, RR or HR of NPC patients comparing smoking with never-smoking; the second was the crude OR, RR or HR.ResultsWe identified 17 case–control studies and 4 cohort studies including 5960 NPC cases and 429 464 subjects. Compared with never smokers, current smokers and ever smokers had a 59% and a 56% greater risk of NPC, respectively. A dose–response relationship was identified in that the risk estimate rose by 15% (p<0.001) with every additional 10 pack-years of smoking, and risk increased with intensity of cigarette smoking (>30 cigarettes per day). Significantly increased risk was only found among male smokers (OR, 1.36; 95% CI 1.15 to 1.60), not among female smokers (OR, 1.58; 95% CI 0.99 to 2.53). Significantly increased risk also existed in the differentiated (OR, 2.34; 95% CI 1.77 to 3.09) and the undifferentiated type of NPC (OR, 1.15; 95% CI 0.90 to 1.46). Moreover, people who started smoking at younger age (<18 years) had a greater risk than those starting later for developing NPC (OR, 1.78; 95% CI 1.41 to 2.25).ConclusionsCigarette smoking was associated with increased risk of NPC, especially for young smokers. However, we did not find statistical significant risks of NPC in women and in undifferentiated type, which might warrant further researches.

Correlation of Histopathological Types of Laryngeal and Nasopharyngeal Mass with PCR Detected Epstein - Barr virus (LMP-1) – A Hospital Based Prospective Study

“…11.11% male non smoker has keratinizing squamous cell carcinoma and 22.22% female non smoker patient has non-Hodgkin lymphoma and 22.2% male smoker and 44.44% male non smoker patients have juvenile nasopharyngeal angiofibroma. A study by M Long et al showed that significantly increased risk was only found among male smokers (OR 1.36), not among female smokers (OR 1.58) and significantly increased risk also existed in the differentiated (OR 2.34) and the undifferentiated type of NPC (OR 1.15) [17].…”

Interleukin-18 promoter genotype is associated with the risk of nasopharyngeal carcinoma in Taiwan

“…In 2017, Long et al reported that cigarette smoking was associated with an increased risk for NPC, especially for subjects who are young, male, and had early-onset, long-term, and undifferentiated type of NPC. 4 However, the authors did not examine the effect of interaction between genotypes (such as IL-18 -607) and smoking on the risk of NPC. Therefore, further investigations are needed to elucidate the detailed mechanisms underlying the interaction between IL-18 and other molecules and environmental factors related to the etiology of NPC.…”

“… 2 Furthermore, studies have shown that cigarette smoking and alcohol consumption constitute the environmental risk factors for NPC. 3 , 4 Mounting evidence indicates that the variant genotypes of the genes related to inflammatory cytokines could modulate the susceptibility of individuals to cancers. 5 – 8 Polymorphisms of these genes may affect the cellular responses to inflammation and the secretion of cytokines by altering the expression and function of the genes.…”

Correlation of Histopathological Types of Laryngeal and Nasopharyngeal Mass with PCR Detected Human Papilloma Virus -16, 18 – A Hospital Based Prospective Study

“…11.11% male nonsmoker has keratinizing squamous cell carcinoma and 22.22% female nonsmoker patient has non-Hodgkin lymphoma and 22.2% male smoker and 44.44% male nonsmoker patients have juvenile nasopharyngeal angiofibroma. A study by M Long et al showed that significantly increased risk was only found among male smokers (OR 1.36), not among female smokers (OR 1.58) and significantly increased risk also existed in the differentiated (OR 2.34) and the undifferentiated type of NPC (OR 1.15) [26].…”