title: Cancer risks from betel quid chewing beyond oral cancer: a multiple-site carcinogen when acting with smoking.
abstract: OBJECTIVE
  This cohort study is to assess the extent of cancer risks of betel quid chewing (without tobacco added) beyond oral cancer, as such information was limited from case-control studies.
  
  
  METHODS
  The cohort, selected from participants in a medical screening program since 1994, consisted of 177,271 adult men with 19.2% chewers of betel quid. As of 2006, out of 4,840 deaths, 1,901 cancer deaths were identified. Mortality hazard ratios (HR) were estimated by Cox proportional hazard model. Life expectancy was calculated by life table method.
  
  
  RESULTS
  One-third of smokers chewed (33%) but most of chewers smoked (90%). Risk for all cancer doubled among chewers (HR = 2.00). Risks of at least six cancer sites were increased among chewers: oral cavity (HR = 12.52), esophagus (HR = 5.64), liver (HR = 2.27), pancreas (HR = 2.67), larynx (HR = 6.24), and lung (HR = 2.43) with risks increased with increasing betel quid amount consumed. All-cancer age-adjusted mortality rates in Taiwan increased 25%, including 223% increase in oral cancer, during the last 20 years when chewing rate increased five- to tenfolds. Chewing on top of smoking increased the risks synergistically, and these two were responsible for at least half (50%) of all cancer deaths among 2 million chewers in Taiwan. Life expectancy of chewers was shorter than non-chewers by 5.93 years at age 20 and 5.55 years at age 40.
  
  
  CONCLUSIONS
  In addition to oral cancer, significant increases were seen among chewers for cancer of the esophagus, liver, pancreas, larynx, lung, and all cancer. Chewing and smoking, as combined by most chewers, interacted synergistically and was responsible for half of all cancer deaths in this group. They were responsible for the recent increases in oral, esophageal, pancreatic, and liver cancer in Taiwan. Chewing and smoking shortened their life span by nearly 6 years.
authors.affiliation: Division of Health Policy Research and Development, Institute of Population Health Sciences, National Health Research Institutes, Zhunan, Miaoli County, Taiwan. cwengood@nhri.org.tw
authors.forename: Chi Pang
authors.initials: CP
authors.lastname: Wen
authors.forename: Min Kuang
authors.initials: MK
authors.lastname: Tsai
authors.forename: Wen Shen Isabella
authors.initials: WS
authors.lastname: Chung
authors.forename: Hui Ling
authors.initials: HL
authors.lastname: Hsu
authors.forename: Yen Chen
authors.initials: YC
authors.lastname: Chang
authors.forename: Hui Ting
authors.initials: HT
authors.lastname: Chan
authors.forename: Po Huang
authors.initials: PH
authors.lastname: Chiang
authors.forename: Ting-Yuan David
authors.initials: TY
authors.lastname: Cheng
authors.forename: Shan Pou
authors.initials: SP
authors.lastname: Tsai
mesh_terms: D000328:Adult; D000368:Aged; D001114:Areca / Q000009:adverse effects*; D002273:Carcinogens / Q000494:pharmacology*; D016022:Case-Control Studies; D015331:Cohort Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000139:chemically induced* / Q000401:mortality; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013624:Taiwan; D055815:Young Adult
chemical_list: D002273:Carcinogens