title: Household inhalants exposure and nasopharyngeal carcinoma risk: a large-scale case-control study in Guangdong, China.
abstract: BACKGROUND
  Epidemiological studies show that cigarette smoking increase the risk of nasopharyngeal carcinoma (NPC), however, whether other common, potentially adverse household inhalants increase NPC risk remains uncertain.
  
  
  METHODS
  We conducted a large case-control study to explore the effects of household inhalants, such as incense, mosquito coil, cooking fumes, and wood combustion, on NPC risk. We recruited 1,845 cases and 2,275 controls from Guangdong province, a high-risk area for NPC in China, to obtain the demographic data and relevant exposure information through face-to-face interviews.
  
  
  RESULTS
  We found that incense burning was associated with NPC risk by comparing frequent incense use with never using incense [OR and 95% confidence interval (CI) = 1.73, (1.43, 2.09)]. Wood fuel use was also associated with NPC risk compared with non-wood fire use [OR and 95% CI = 1.95, (1.65, 2.31)]. More intriguingly, we observed a significant addictive interaction between frequent incense burning and heavy cigarette smoking on NPC risk [synergistic index (SI) = 1.67; 95% CI: 1.01, 2.76]. We also found a significant joint effect between wood fuel use and NPC family history for NPC risk (SI = 1.77; 95% CI: 1.06, 2.96). However, neither mosquito oil nor cooking fumes were associated with NPC risk.
  
  
  CONCLUSIONS
  Our study shows that incense smoke is not only the potential independent risk factor but also co-contributes with cigarette smoking to NPC risk. Moreover, wood combustion is another potential environmental risk factor and exerts a joint effect with NPC family history on NPC.
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, 651 Dongfengdong Road, Guangzhou, Guangdong, 510060, China. heyq@sysucc.org.cn.
authors.forename: Yong-Qiao
authors.initials: YQ
authors.lastname: He
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, 651 Dongfengdong Road, Guangzhou, Guangdong, 510060, China. xuewq@sysucc.org.cn.
authors.forename: Wen-Qiong
authors.initials: WQ
authors.lastname: Xue
authors.affiliation: Department of Radiation Oncology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, 510060, China. shenguop@mail.sysu.edu.cn.
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, 651 Dongfengdong Road, Guangzhou, Guangdong, 510060, China. 314373000@qq.com.
authors.forename: Ling-Ling
authors.initials: LL
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, 651 Dongfengdong Road, Guangzhou, Guangdong, 510060, China. zengyx@sysucc.org.cn.
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-Sen University Cancer Center, 651 Dongfengdong Road, Guangzhou, Guangdong, 510060, China. jiawh@sysucc.org.cn.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Jia
mesh_terms: D000328:Adult; D016902:Air Pollution, Indoor / Q000009:adverse effects*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005260:Female; D006795:Household Products / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects