title: Gastric cancer risk in relation to tobacco use and alcohol drinking in Kerala, India--Karunagappally cohort study.
abstract: OBJECTIVE
  To assess the risk of gastric cancer (GC) in relation to tobacco use and alcohol drinking in the Karunagappally cohort in Kerala, South India.
  
  
  METHODS
  This study examined the association of tobacco use and alcohol drinking with GC incidence among 65553 men aged 30-84 in the Karunagappally cohort. During the period from 1990-2009, 116 GC cases in the cohort were identified as incident cancers. These cases were identified from the population-based cancer registry. Information regarding risk factors such as socioeconomic factors and tobacco and alcohol habits of cohort members were collected from the database of the baseline survey conducted during 1990-1997. The relative risks (RRs) and the corresponding 95% confidence intervals (95%CIs) for tobacco use were obtained from Poisson regression analysis of grouped survival data, considering age, follow-up period, occupation and education.
  
  
  RESULTS
  Bidi smoking was associated with GC risk (P = 0.042). The RR comparing current versus never smokers was 1.6 (95%CI: 1.0-2.5). GC risk was associated with the number of bidis smoked daily (P = 0.012) and with the duration of bidi smoking (P = 0.036). Those who started bidi smoking at younger ages were at an elevated GC risk; the RRs for those starting bidi smoking under the age of 18 and ages 18-22 were 2.0 (95%CI: 1.0-3.9) and 1.8 (95%CI: 1.1-2.9), respectively, when their risks were compared with lifetime non-smokers of bidis. Bidi smoking increased the risk of GC among never cigarette smokers more evidently (RR = 2.2; 95%CI: 1.3-4.0). GC risk increased with the cumulative amount of bidi smoking, which was calculated as the number of bidis smoked per day x years of smoking (bidi-year; P = 0.017). Cigarette smoking, tobacco chewing or alcohol drinking was not significantly associated with GC risk.
  
  
  CONCLUSIONS
  Among a male cohort in South India, gastric cancer risk increased with the number and duration of bidi smoking.
authors.affiliation: Padmavathy Amma Jayalekshmi, Natural Background Radiation Cancer Registry, Karunagappally, Kerala 690536, India.
authors.forename: Padmavathy Amma
authors.initials: PA
authors.lastname: Jayalekshmi
authors.affiliation: Padmavathy Amma Jayalekshmi, Natural Background Radiation Cancer Registry, Karunagappally, Kerala 690536, India.
authors.forename: Soroush
authors.initials: S
authors.lastname: Hassani
authors.affiliation: Padmavathy Amma Jayalekshmi, Natural Background Radiation Cancer Registry, Karunagappally, Kerala 690536, India.
authors.forename: Athira
authors.initials: A
authors.lastname: Nandakumar
authors.affiliation: Padmavathy Amma Jayalekshmi, Natural Background Radiation Cancer Registry, Karunagappally, Kerala 690536, India.
authors.forename: Chihaya
authors.initials: C
authors.lastname: Koriyama
authors.affiliation: Padmavathy Amma Jayalekshmi, Natural Background Radiation Cancer Registry, Karunagappally, Kerala 690536, India.
authors.forename: Paul
authors.initials: P
authors.lastname: Sebastian
authors.affiliation: Padmavathy Amma Jayalekshmi, Natural Background Radiation Cancer Registry, Karunagappally, Kerala 690536, India.
authors.forename: Suminori
authors.initials: S
authors.lastname: Akiba
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects* / Q000453:epidemiology; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D013274:Stomach Neoplasms / Q000453:epidemiology*; D013997:Time Factors; D062789:Tobacco Products / Q000009:adverse effects*
keywords: Alcohol drinking; Bidi smoking; Gastric cancer; India; Kerala; The Karunagappally cohort