Smoking and nasopharyngeal cancer: individual data meta-analysis of six prospective studies on 334 935 men

Jia Huang Lin, Chi Pang Wen, Chao Qiang Jiang, Jian-Min Yuan, Chien Jen Chen, Sai Yin Ho, Wayne Gao, Weisen Zhang, Renwei Wang, Yin-Chu Chien, Lin Xu, Xifeng Wu, Ya Li Jin, Woon-Puay Koh, Wan-Lun Hsu, Feng Zhu, Christopher Wen, Tong Zhu, June Han Lee, Zhi-Ming MaiMaria Li Lung, Tai-Hing Lam

Research output: Contribution to journalArticlepeer-review


The role of smoking in nasopharyngeal carcinoma (NPC) remains uncertain, especially in endemic regions. We conducted an individual participant data (IPD) meta-analysis of prospective cohort studies to investigate the associations between smoking exposure and risk of NPC.We obtained individual participant data of 334 935 male participants from six eligible population-based cohorts in NPC-endemic regions, including two each in Guangzhou and Taiwan, and one each in Hong Kong and Singapore. We used one- and two-stage approaches IPD meta-analysis and Cox proportional hazard models to calculate hazard ratios (HRs) and 95\CIs) of NPC for smoking exposure adjusting for age and drinking status.During 2 961 315 person-years of follow-up, 399 NPC evens were ascertained. Risks of NPC were higher in ever versus never smokers (HRone-stage = 1.32, 95\.07-1.63, P = 0.0088; HRtwo-stage = 1.27, 1.01-1.60, 0.04). These positive associations appeared to be stronger in ever smokers who consumed 16+ cigarettes/day (HRone-stage = 1.67, 95\.29-2.16, P = 0.0001), and in those who started smoking at age younger than 16 (2.16, 1.33-3.50, 0.0103), with dose-response relationships (P-values for trend = 0.0028 and 0.0103, respectively). Quitting (versus daily smoking) showed a small reduced risk (stopped for 5+ years: HRone-stage = 0.91, 95\.60-1.39, P = 0.66; for former smokers: HRtwo-stage = 0.84, 0.61-1.14, 0.26).This first IPD meta-analysis from six prospective cohorts in endemic regions has provided robust observational evidence that smoking increased NPC risk in men. NPC should be added to the 12–16 cancer sites known to be tobacco-related cancers. Strong tobacco control policies, preventing young individuals from smoking, would reduce NPC risk in endemic regions.
Original languageEnglish
Pages (from-to)975-986
Number of pages12
JournalInternational Journal of Epidemiology
Issue number3
Publication statusPublished - Mar 2021


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