title: Effects of bidi smoking on all-cause mortality and cardiorespiratory outcomes in men from south Asia: an observational community-based substudy of the Prospective Urban Rural Epidemiology Study (PURE).
abstract: Bidis are minimally regulated, inexpensive, hand-rolled tobacco products smoked in south Asia. We examined the effects of bidi smoking on baseline respiratory impairment, and prospectively collected data for all-cause mortality and cardiorespiratory events in men from this region.
  
  
  
  This substudy of the international, community-based Prospective Urban Rural Epidemiology (PURE) study was done in seven centres in India, Pakistan, and Bangladesh. Men aged 35-70 years completed spirometry testing and standardised questionnaires at baseline and were followed up yearly. We used multilevel regression to compare cross-sectional baseline cardiorespiratory symptoms, spirometry measurements, and follow-up events (all-cause mortality, cardiovascular events, respiratory events) adjusted for socioeconomic status and baseline risk factors between non-smokers, light smokers of bidis or cigarettes (≤10 pack-years), heavy smokers of cigarettes only (>10 pack-years), and heavy smokers of bidis (>10 pack-years).
  
  
  
  14 919 men from 158 communities were included in this substudy (8438 non-smokers, 3321 light smokers, 959 heavy cigarette smokers, and 2201 heavy bidi smokers). Mean duration of follow-up was 5·6 years (range 1-13). The adjusted prevalence of self-reported chronic wheeze, cough or sputum, dyspnoea, and chest pain at baseline increased across the categories of non-smokers, light smokers, heavy cigarette smokers, and heavy bidi smokers (p<0·0001 for association). Adjusted cross-sectional age-related changes in forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) ratio were larger for heavy bidi smokers than for the other smoking categories. Hazard ratios (relative to non-smokers) showed increasing hazards for all-cause mortality (light smokers 1·28 [95% CI 1·02-1·62], heavy cigarette smokers 1·59 [1·13-2·24], heavy bidi smokers 1·56 [1·22-1·98]), cardiovascular events (1·45 [1·13-1·84], 1·47 [1·05-2·06], 1·55 [1·17-2·06], respectively) and respiratory events (1·30 [0·91-1·85], 1·21 [0·70-2·07], 1·73 [1·23-2·45], respectively) across the smoking categories.
  
  
  
  Bidi smoking is associated with severe baseline respiratory impairment, all-cause mortality, and cardiorespiratory outcomes. Stricter controls and regulation of bidis are needed to reduce the tobacco-related disease burden in south Asia.
  
  
  
  Population Health Research Institute, Canadian Institutes of Health Research, and Heart and Stroke Foundation of Ontario.
authors.affiliation: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada; Department of Medicine, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada. Electronic address: duongmy@mcmaster.ca.
authors.forename: MyLinh
authors.initials: M
authors.lastname: Duong
authors.affiliation: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Sumathy
authors.initials: S
authors.lastname: Rangarajan
authors.affiliation: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Medicine, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Kieran
authors.initials: K
authors.lastname: Killian
authors.affiliation: Division of Epidemiology and Population Health, St John's Research Institute, Bengaluru, India.
authors.forename: Prem
authors.initials: P
authors.lastname: Mony
authors.affiliation: Division of Epidemiology and Population Health, St John's Research Institute, Bengaluru, India.
authors.forename: Sumathi
authors.initials: S
authors.lastname: Swaminathan
authors.affiliation: Division of Epidemiology and Population Health, St John's Research Institute, Bengaluru, India.
authors.forename: Ankalmadagu Venkatsubbareddy
authors.initials: AV
authors.lastname: Bharathi
authors.affiliation: Department of Pulmonary Medicine, Medical College, Thiruvananthapuram, Kerala, India; Health Action by People, Thiruvananthapuram, Kerala, India.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Nair
authors.affiliation: Health Action by People, Thiruvananthapuram, Kerala, India; Dr Somervell Memorial CSI Medical College, Karakonam, Thiruvananthapuram, Kerala, India.
authors.forename: Krishnapillai
authors.initials: K
authors.lastname: Vijayakumar
authors.affiliation: Fortis Escorts Hospitals, JLN Marg, Jaipur, India.
authors.forename: Indu
authors.initials: I
authors.lastname: Mohan
authors.affiliation: Fortis Escorts Hospitals, JLN Marg, Jaipur, India.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Madras Diabetes Research Foundation, Chennai, India.
authors.forename: Deepa
authors.initials: D
authors.lastname: Mohan
authors.affiliation: Madras Diabetes Research Foundation, Chennai, India.
authors.forename: Shanthi
authors.initials: S
authors.lastname: Rani
authors.affiliation: Madras Diabetes Research Foundation, Chennai, India.
authors.forename: Viswanathan
authors.initials: V
authors.lastname: Mohan
authors.affiliation: Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan; Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Romaina
authors.initials: R
authors.lastname: Iqbal
authors.affiliation: Department of Medicine, Aga Khan University, Karachi, Pakistan.
authors.forename: Khawar
authors.initials: K
authors.lastname: Kazmi
authors.affiliation: Independent University, Dhaka, Bangladesh.
authors.forename: Omar
authors.initials: O
authors.lastname: Rahman
authors.affiliation: Independent University, Dhaka, Bangladesh.
authors.forename: Rita
authors.initials: R
authors.lastname: Yusuf
authors.affiliation: Post Graduate Institute of Medical Education and Research (PGIMER) School of Public Health, Chandigarh, India.
authors.forename: Lakshmi Venkata Maha
authors.initials: LV
authors.lastname: Pinnaka
authors.affiliation: Post Graduate Institute of Medical Education and Research (PGIMER) School of Public Health, Chandigarh, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Medicine, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: O'Byrne
authors.affiliation: Population Health Research Institute, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada; Department of Medicine, McMaster University and Hamilton Health Sciences, Hamilton, ON, Canada.
authors.forename: Salim
authors.initials: S
authors.lastname: Yusuf
mesh_terms: D000328:Adult; D001459:Bangladesh / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000150:complications* / Q000401:mortality; D002423:Cause of Death; D003430:Cross-Sectional Studies; D016021:Epidemiologic Studies; D005541:Forced Expiratory Volume; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D015995:Prevalence; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000150:complications* / Q000401:mortality; D012307:Risk Factors; D012424:Rural Population; D013147:Spirometry; D011795:Surveys and Questionnaires; D062789:Tobacco Products / Q000009:adverse effects*; D000073869:Tobacco Smoking / Q000009:adverse effects*; D014029:Tobacco Use Disorder / Q000150:complications*; D014797:Vital Capacity