title: Tobacco smoking, family history, and the risk of nasopharyngeal carcinoma: a case-referent study in Hong Kong Chinese.
abstract: OBJECTIVE
  This study aimed to investigate the associations of tobacco smoking and family history of nasopharyngeal carcinoma (NPC) with the risk of NPC in Hong Kong Chinese.
  
  
  METHODS
  Between June 2010 and December 2012, we conducted a case-referent study with 352 incident cases and 410 referents in Hong Kong. We collected information on tobacco smoking and family history of NPC via face-to-face interviews.
  
  
  RESULTS
  There were 174 (49.4%) and 131 (32.0%) ever-smokers among cases and referents, respectively. The adjusted odds ratio (OR) for NPC related to current smoking was 1.67 [95% confidence interval (CI) 1.06, 2.61]. Exposure-response relationships were observed between years and total pack-years of smoking, and NPC risk (p = 0.001 and p = 0.018, respectively). History of NPC in first-degree relatives was associated with an increased NPC risk (adjusted OR = 4.52, 95% CI 2.39, 8.55). The increased NPC risk associated with sibling history (adjusted OR = 6.80, 95% CI 2.63, 17.56) was higher than that for parental history (adjusted OR = 3.04, 95% CI 1.27, 7.25). The adjusted OR for ever-smokers with family history using never-smokers without family history as the reference was 4.54 (95% CI 1.67, 12.34).
  
  
  CONCLUSIONS
  This study verified the important roles of tobacco smoking and family history on NPC risk among Hong Kong Chinese. The provided evidence supported the knowledge that both environmental exposures and inherited susceptibility contributed to the risk of NPC.
authors.affiliation: The Jockey Club School of Public Health and Primary Care, The Chinese University of Hong Kong, 4/F, School of Public Health Building, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China, shaohua1983-man@163.com.
authors.forename: Shao-Hua
authors.initials: SH
authors.lastname: Xie
authors.forename: Ignatius Tak-Sun
authors.initials: IT
authors.lastname: Yu
authors.forename: Lap Ah
authors.initials: LA
authors.lastname: Tse
authors.forename: Joseph Siu Kie
authors.initials: JS
authors.lastname: Au
authors.forename: June Sze Man
authors.initials: JS
authors.lastname: Lau
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics; D002277:Carcinoma / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D016022:Case-Control Studies; D004781:Environmental Exposure; D005260:Female; D020022:Genetic Predisposition to Disease; D006723:Hong Kong; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000235:genetics; D055815:Young Adult