Quantifying the association of low-intensity and late initiation of tobacco smoking with total and cause-specific mortality in Asia

Jae Jeong Yang, Danxia Yu, Xiao Ou Shu, Neal D. Freedman, Wanqing Wen, Shafiur Rahman, Sarah K. Abe, Eiko Saito, Prakash C. Gupta, Jiang He, Shoichiro Tsugane, Yu Tang Gao, Yong Bing Xiang, Jian Min Yuan, Yasutake Tomata, Ichiro Tsuji, Yumi Sugawara, Keitaro Matsuo, Yoon Ok Ahn, Sue K. ParkYu Chen, Wen Harn Pan, Mangesh Pednekar, Dongfeng Gu, Norie Sawada, Hui Cai, Hong Lan Li, Woon Puay Koh, Renwei Wang, Shu Zhang, Seiki Kanemura, Hidemi Ito, Myung Hee Shin, Pei Ei Wu, Keun Young Yoo, Habibul Ahsan, Kee Seng Chia, Paolo Boffetta, Manami Inoue, Daehee Kang, John D. Potter, Wei Zheng

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish (US)
Pages (from-to)328-335
Number of pages8
JournalTobacco control
Issue number3
StatePublished - May 1 2021


  • prevention
  • smoking caused disease
  • socioeconomic status
  • Prospective Studies
  • Humans
  • Middle Aged
  • Adult
  • Asia/epidemiology
  • Smoking/adverse effects
  • Tobacco Smoking/adverse effects
  • Cause of Death

ASJC Scopus subject areas

  • Health(social science)
  • Public Health, Environmental and Occupational Health


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