title: Oral Hygiene and Risk of Nasopharyngeal Carcinoma-A Population-Based Case-Control Study in China.
abstract: The association between oral health and risk of nasopharyngeal carcinoma (NPC) is largely unknown. Further understanding could shed light on potential pathogenic mechanisms and preventive measures.
  
  
  
  We conducted a population-based case-control study in southern China between 2010 and 2014. We enrolled 2,528 incident NPC cases, aged 20-74 years, and 2,596 controls, randomly selected from the total population registers, with frequency matching to the 5-year age and sex distribution of the cases by geographic region. We interviewed subjects using a structured questionnaire inquiring about oral health indicators and potential confounding factors. We used unconditional logistic regression to estimate multivariate-adjusted ORs with 95% confidence intervals (CI).
  
  
  
  A higher number of filled teeth was associated with an elevated risk of NPC. Individuals with 1 to 3 and more than 3 teeth filled versus none had adjusted ORs of 1.25 (95% CI, 1.06-1.49) and 1.55 (95% CI, 1.13-2.12), respectively (Ptrend = 0.002). Conversely, the adjusted OR for those who brushed teeth twice or more per day versus once or less per day was 0.62 (95% CI, 0.55-0.70). We detected a borderline significant positive association with earlier age at first adult tooth loss.
  
  
  
  Our study suggested a positive association between some indicators of poor oral health and risk of NPC. Further studies are needed to confirm whether the findings are causal and, if so, to further explain the underlying mechanisms.
  
  
  
  Improvement of oral hygiene might contribute to reducing NPC risk. Cancer Epidemiol Biomarkers Prev; 25(8); 1201-7. ©2016 AACR.
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Exponent, Inc., Health Sciences Practice, Menlo Park, California. Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California.
authors.forename: Ellen T
authors.initials: ET
authors.lastname: Chang
authors.affiliation: Department of Cancer Prevention Center, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China. State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Clinical Laboratory, Wuzhou Red Cross Hospital, Wuzhou, Guangxi, China. Wuzhou Health System Key Laboratory for Nasopharyngeal Carcinoma Etiology and Molecular Mechanism, Wuzhou, Guangxi, China.
authors.forename: Yonglin
authors.initials: Y
authors.lastname: Cai
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China. Key Laboratory of High-Incidence-Tumor Prevention & Treatment (Guangxi Medical University), Ministry of Education, Nanning, Guangxi, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: State Key Laboratory for Infectious Diseases Prevention and Control, Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Guomin
authors.initials: G
authors.lastname: Chen
authors.affiliation: Department of Cancer Prevention Center, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China. State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China.
authors.forename: Shang-Hang
authors.initials: SH
authors.lastname: Xie
authors.affiliation: Department of Cancer Prevention Center, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China. State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China.
authors.forename: Su-Mei
authors.initials: SM
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China.
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China.
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Jia
authors.affiliation: Department of Clinical Laboratory, Wuzhou Red Cross Hospital, Wuzhou, Guangxi, China. Wuzhou Health System Key Laboratory for Nasopharyngeal Carcinoma Etiology and Molecular Mechanism, Wuzhou, Guangxi, China.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Cangwu Institute for Nasopharyngeal Carcinoma Control and Prevention, Wuzhou, Guangxi, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liao
authors.affiliation: Key Laboratory of High-Incidence-Tumor Prevention & Treatment (Guangxi Medical University), Ministry of Education, Nanning, Guangxi, China.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ingemar
authors.initials: I
authors.lastname: Ernberg
authors.affiliation: Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington. Department of Epidemiology, University of Washington, Seattle, Washington.
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Vaughan
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts.
authors.forename: Hans-Olov
authors.initials: HO
authors.lastname: Adami
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China. Key Laboratory of High-Incidence-Tumor Prevention & Treatment (Guangxi Medical University), Ministry of Education, Nanning, Guangxi, China.
authors.forename: Guangwu
authors.initials: G
authors.lastname: Huang
authors.affiliation: State Key Laboratory for Infectious Diseases Prevention and Control, Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
authors.forename: Yi
authors.initials: Y
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, Guangzhou, Guangdong, China.
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Zeng
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. weimin.ye@ki.se.
authors.forename: Weimin
authors.initials: W
authors.lastname: Ye
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000209:etiology*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D003731:Dental Caries / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000209:etiology*; D016017:Odds Ratio; D009909:Oral Health / Q000706:statistics & numerical data; D009910:Oral Hygiene / Q000706:statistics & numerical data*; D011159:Population Surveillance; D011247:Pregnancy; D012307:Risk Factors; D011795:Surveys and Questionnaires; D016388:Tooth Loss / Q000453:epidemiology; D055815:Young Adult