Article Text

Download PDFPDF
Quantifying the association of low-intensity and late initiation of tobacco smoking with total and cause-specific mortality in Asia
  1. Jae Jeong Yang1,
  2. Danxia Yu1,
  3. Xiao-Ou Shu1,
  4. Neal D Freedman2,
  5. Wanqing Wen1,
  6. Shafiur Rahman3,4,
  7. Sarah K Abe5,
  8. Eiko Saito6,
  9. Prakash C Gupta7,
  10. Jiang He8,
  11. Shoichiro Tsugane5,
  12. Yu-Tang Gao9,
  13. Yong-Bing Xiang9,
  14. Jian-Min Yuan10,11,
  15. Yasutake Tomata12,
  16. Ichiro Tsuji12,
  17. Yumi Sugawara12,
  18. Keitaro Matsuo13,14,
  19. Yoon-Ok Ahn15,
  20. Sue K Park15,16,17,
  21. Yu Chen18,
  22. Wen-Harn Pan19,
  23. Mangesh Pednekar7,
  24. Dongfeng Gu20,
  25. Norie Sawada5,
  26. Hui Cai1,
  27. Hong-Lan Li9,
  28. Woon-Puay Koh21,22,
  29. Renwei Wang10,11,
  30. Shu Zhang12,
  31. Seiki Kanemura12,
  32. Hidemi Ito23,24,
  33. Myung-Hee Shin25,
  34. Pei-Ei Wu19,
  35. Keun-Young Yoo15,
  36. Habibul Ahsan26,
  37. Kee Seng Chia22,
  38. Paolo Boffetta27,
  39. Manami Inoue5,
  40. Daehee Kang15,16,17,
  41. John D Potter28,29,30,
  42. Wei Zheng1
  1. 1Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA
  2. 2Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
  3. 3Research Center for Child Mental Development, Hamamatsu University School of Medicine, Hamamatsu city, Shizuoka, Japan
  4. 4Division of Prevention, Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
  5. 5Epidemiology and Prevention Group, Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
  6. 6Division of Cancer Statistics and Integration, Center for Cancer Control and Information Services, National Cancer Center, Tokyo, Japan
  7. 7Healis Sekhsaria Institute for Public Health, Navi Mumbai, Maharashtra, India
  8. 8Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA, USA
  9. 9State Key Laboratory of Oncogene and Related Genes & Department of Epidemiology, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
  10. 10The University of Pittsburgh Cancer Institute, Pittsburgh, PA, USA
  11. 11Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA
  12. 12Division of Epidemiology, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
  13. 13Division of Cancer Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya, Japan
  14. 14Division of Cancer Epidemiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
  15. 15Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, South Korea
  16. 16Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, South Korea
  17. 17Cancer Research Institute, Seoul National University, Seoul, South Korea
  18. 18Department of Population Health, New York University School of Medicine, New York, NY, USA
  19. 19Institute of Biomedical Sciences, Academia Sinica BRC, Taipei, Taiwan
  20. 20Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
  21. 21Health Services and Systems Research, Duke-NUS Graduate Medical School, Singapore
  22. 22Saw Swee Hock School of Public Health, National University of Singapore, Singapore
  23. 23Division of Cancer Information and Control, Aichi Cancer Center Research Institute, Nagoya, Japan
  24. 24Division of Descriptive Cancer Epidemiology, Nagoya University Graduate School of Medicine, Nagoya, Japan
  25. 25Department of Social and Preventive Medicine, Sungkyunkwan University School of Medicine, Seoul, South Korea
  26. 26Department of Health Studies, Center for Cancer Epidemiology and Prevention, University of Chicago, Chicago, IL, USA
  27. 27Icahn School of Medicine at Mount Sinai, New York, NY, USA
  28. 28Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
  29. 29Centre for Public Health Research, Massey University, Wellington, New Zealand
  30. 30Department of Epidemiology, University of Washington, Seattle, WA, USA
  1. Correspondence to Dr Wei Zheng, Division of Epidemiology, Department of Medicine, Vanderbilt Epidemiology Center, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232-2102, USA; wei.zheng{at}


Background Little is known about the health harms associated with low-intensity smoking in Asians who, on average, smoke fewer cigarettes and start smoking at a later age than their Western counterparts.

Methods In this pooled analysis of 738 013 Asians from 16 prospective cohorts, we quantified the associations of low-intensity (<5 cigarettes/day) and late initiation (≥35 years) of smoking with mortality outcomes. HRs and 95% CIs were estimated for each cohort by Cox regression. Cohort-specific HRs were pooled using random-effects meta-analysis.

Findings During a mean follow-up of 11.3 years, 92 068 deaths were ascertained. Compared with never smokers, current smokers who consumed <5 cigarettes/day or started smoking after age 35 years had a 16%–41% increased risk of all-cause, cardiovascular disease (CVD), respiratory disease mortality and a >twofold risk of lung cancer mortality. Furthermore, current smokers who started smoking after age 35 and smoked <5 cigarettes/day had significantly elevated risks of all-cause (HRs (95% CIs)=1.14 (1.05 to 1.23)), CVD (1.27 (1.08 to 1.49)) and respiratory disease (1.54 (1.17 to 2.01)) mortality. Even smokers who smoked <5 cigarettes/day but quit smoking before the age of 45 years had a 16% elevated risk of all-cause mortality; however, the risk declined further with increasing duration of abstinence.

Conclusions Our study showed that smokers who smoked a small number of cigarettes or started smoking later in life also experienced significantly elevated all-cause and major cause-specific mortality but benefited from cessation. There is no safe way to smoke—not smoking is always the best choice.

  • smoking caused disease
  • prevention
  • socioeconomic status

Statistics from


  • Contributors WZ conceived, designed and supervised the study. JJY, DY, X-OS, NDF, WW and WZ contributed to data analysis, data interpretation and writing the manuscript. X-OS, SR, SKA, ES, PCG, JH, ST, Y-TG, Y-BX, J-MY, YT, IT, YS, KM, Y-OA, SKP, YC, W-HP, MP, DG, NS, HC, H-LL, W-PK, RW, SZ, SK, HI, M-HS, P-EW, K-YY, HA, KSC, PB, MI, DK, JDP and WZ contributed to data collection and provided study materials and administrative/technical support. All authors contributed to critical revision of the manuscript for important intellectual content and approved the final version of the manuscript.

  • Funding This work was supported by research funds from the Anne Potter Wilson Chair endowment and National Institutes of Health grants (UM1CA182910 to Dr Zheng and UM1CA173640 to Dr Shu) at Vanderbilt University Medical Center. Participating cohort studies (funding sources) in the consortium are: China National Hypertension Survey Epidemiology Follow-up Study (CHEFS, funding sources: American Heart Association (9750612N), NHLBI (U01-HL072507), Chinese Academy of Medical Sciences); Shanghai Cohort Study (SCS, funding sources: NIH (R01CA0403092, R01CA144034, UM1CA182876)); Shanghai Men’s Health Study (SMHS, funding sources: NIH (R01-CA82729)); Shanghai Women’s Health Study (SWHS, funding sources: NIH (R37-CA70867)); Korea Multicenter Cancer Cohort (KMCC, funding sources: Ministry of Education, Science and Technology, Korea, National Research Foundation of Korea grant 2009-0087452); Seoul Male Cancer Cohort (Seoul Male, funding sources: National R&D Program for Cancer Control, Ministry of Health & Welfare, Republic of Korea (0520160-1)); Singapore Chinese Health Study (SCHS, funding sources: NIH (R01CA55069, R35CA53890, R01CA80205, R01CA144034, UM1CA182876)); CardioVascular Disease risk FACtor Two-township Study (CVDFACTS, funding sources: Department of Health, Taiwan (DOH80-27, DOH81-021, DOH8202-1027, DOH83-TD-015 and DOH84-TD-006)); Mumbai Cohort Study (Mumbai, funding sources: International Agency for Research on Cancer, Clinical Trials Service Unit/Oxford University, World Health Organization) and Health Effects of Arsenic Longitudinal Study (HEALS, funding sources: NIH grants P42ES010349, R01CA102484 and R01CA107431). All Japanese cohorts—three Prefecture Cohort Study Aichi (3-Prefecture Aichi), Japan Public Health Center-based Prospective Study (JPHC1 and JPHC2), Three Prefecture Cohort Study Miyagi (3-Prefecture Miyagi), Miyagi Cohort Study (Miyagi) and Ohsaki National Health Insurance Cohort Study (Ohsaki)—are supported by the Grant-in-aid for Cancer Research, the Grant for the Third Term Comprehensive Control Research for Cancer, the Grant for Health Services, the Grant for Medical Services for Aged and Health Promotion, the Grant for Comprehensive Research on Cardiovascular and Lifestyle-Related Diseases from the Ministry of Health, Labour and Welfare, Japan and the Grant for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan. Japan Public Health Center-Based Prospective Study (JPHC1 and JPHC2) are also supported by the National Cancer Center Research and Development Fund. The corresponding author had full access to all the data and had final responsibility for the decision to submit for publication.

  • Disclaimer The funder of the study had no role in study design, data collection, data analysis, data interpretation or writing of the report.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Ethics approval The current pooling project and individual cohort studies were approved by relevant Institutional Review Boards and ethics committees.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available on reasonable request. Data access can be through permission from the Asia Cohort Consortium only; please find more details on and send any inquiries to the Asia Cohort Consortium Coordinating Center at

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.