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Mortality and smoking in Hong Kong: case-control study of all adult deaths in 1998

BMJ 2001; 323 doi: https://doi.org/10.1136/bmj.323.7309.361 (Published 18 August 2001) Cite this as: BMJ 2001;323:361
  1. T H Lam (commed{at}hkucc.hku.hk), chair professor in community medicinea,
  2. S Y Ho, postdoctoral fellowa,
  3. A J Hedley, chair professor in community medicinea,
  4. K H Mak, consultant in community medicineb,
  5. R Peto, co-directorc
  1. a Department of Community Medicine, University of Hong Kong, Patrick Manson Building South Wing, 7 Sassoon Road, Hong Kong
  2. b Department of Health, Government of the Hong Kong Special Administrative Region
  3. c CTSU, University of Oxford, Oxford OX2 6HE
  1. Correspondence to: T H Lam
  • Accepted 5 July 2001

Abstract

Objective: To assess the mortality currently associated with smoking in Hong Kong, and, since cigarette consumption reached its peak 20 years earlier in Hong Kong than in mainland China, to predict mortality in China 20 years hence.

Design: Case-control study. Past smoking habits of all Chinese adults in Hong Kong who died in 1998 (cases) were sought from those registering the death.

Setting: All the death registries in Hong Kong.

Participants: 27 507 dead cases (81% of all registered deaths) and 13 054 live controls aged ≥35 years.

Main outcome measures: Mortality from all causes and from specific causes.

Results: In men aged 35-69 the adjusted risk ratios (and 95% confidence intervals) comparing smokers with non-smokers were 1.92 (1.70 to 2.16) for all deaths, 2.22 (1.94 to 2.55) for neoplastic deaths, 2.60 (2.10 to 3.21) for respiratory deaths (including tuberculosis, risk ratio 2.54), and 1.68 (1.43 to 1.97) for vascular deaths (each P<0.0001). In women aged 35-69 the corresponding risk ratios were 1.62 (1.40 to 1.88) for all deaths, 1.60 (1.33 to 1.93) for neoplastic deaths, 3.13 (2.21 to 4.44) for respiratory deaths, and 1.55 (1.20 to 1.99) for vascular deaths (each P<0.001). If these associations with smoking are largely or wholly causal then, among all registered deaths at ages 35-69 in 1998, tobacco caused about 33% (2534/7588) of all male deaths and 5% (169/3341) of all female deaths (hence 25% of all deaths at these ages). At older ages tobacco seemed to be the cause of 15% (3017/20 420) of all deaths.

Conclusions: Among middle aged men the proportion of deaths caused by smoking is more than twice as big in Hong Kong now (33%) as in mainland China 10 years earlier. This supports predictions of a large increase in tobacco attributable mortality in China as a whole.

What is already known on this topic

What is already known on this topic China, with 20% of the world's population, smokes 30% of the world's cigarettes. Men smoke most, and the proportion of male deaths at ages 35-69 attributable to tobacco has been predicted to rise over the next few decades from 13% (in 1988) to about 33%

In Hong Kong cigarette consumption reached its peak 20 years earlier than in mainland China, so the epidemic of male deaths from tobacco should now be at a more advanced stage

What this study adds

What this study adds In the general population of Hong Kong in 1998 tobacco caused about 33% of all male deaths at ages 35-69 plus 5% of all female deaths, and hence 25% of all deaths at these ages

In the male smokers tobacco caused about half of all deaths at ages 35-69 The hazards now seen in Hong Kong foreshadow a substantial increase in tobacco deaths among middle aged men in mainland China over the next few decades if current smoking patterns persist

Footnotes

  • Funding Hong Kong Health Services Research Committee (631012) and Hong Kong Council on Smoking and Health, plus direct support to CTSU by the Imperial Cancer Research Fund and the Medical Research Council.

  • Competing interests None declared.

  • Accepted 5 July 2001
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