BMJ  2003;327:502 (30 August), doi:10.1136/bmj.327.7413.502-a

Letter

Passive smoking

Secondhand smoke does cause respiratory disease

Editor—The report by Enstrom and Kabat confirms that exposure to secondhand smoke causes injury to the respiratory system with the finding of a combined increased mortality risk for men and women for chronic obstructive pulmonary disease (relative risk 1.65, 95% confidence interval 1.0 to 2.73).¹ This is consistent with other investigations that show the sensitivity of the respiratory system to secondhand smoke at all ages and in different settings. In Hong Kong several studies have shown that the exposure of infants to secondhand smoke in utero or postnatally in the home was linked to higher consultation rates and hospitalisation for respiratory and other illnesses.² Smoking in the home was clearly associated with bronchitic symptoms in a cohort of primary school children, independently of ambient air pollution.³ In an adult work-force, workplace exposures to passive smoking were associated with significant excess risks (66% to 212%) for all respiratory symptoms and increased healthcare costs.⁴ In a population survey the prevalence of second-hand smoke exposures at work was 47.5% among non-smoking full time workers compared with only 26% at home. People exposed at work were 37% more likely to consult a doctor for respiratory illness. The increased healthcare costs for primary care alone among three million workers was estimated at US$29m (£18m; €26m) annually.⁵ Four independent case control studies on lung cancer and passive smoking in Hong Kong, reviewed by the United States Environmental Protection Agency, gave an overall relative risk of 1.48 (1.21 to 1.81).

In other words, we have epidemics of respiratory disease in Hong Kong caused by secondhand smoke. However, because of the way in which the Enstrom and Kabat paper was presented little or no attention will be paid in media reports to the findings on mortality risks from respiratory disease.

Department of Community Medicine, University of Hong Kong, Hong Kong Special Administrative Region, China commed{at}hkucc.hku.hk

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Competing interests: AJH is a former chairman of the Hong Kong Council on Smoking and Health (COSH). THL is current vice chairman of COSH. All of the authors conduct research on the health effects of active and passive smoking and have received research funds, through their employer, the University of Hong Kong, to support their work.

References

1. Enstrom JE, Kabat, GC. Environmental tobacco smoke and tobacco related mortality in a prospective study of Californians, 1960-98. BMJ 2003;326: 1057. (17 May.)[Abstract/Free Full Text]
2. Lam TH, Leung GM, Ho LM. The effects of environmental tobacco smoke on health services utilization in the first eighteen months of life. Pediatrics 2001;107: e91.[Abstract/Free Full Text]
3. Peters J, Hedley AJ, Wong CM, Lam TH, Ong SG, Liu J, et al. Effects of an ambient air pollution intervention and environmental tobacco smoke on children's respiratory health in Hong Kong. Int J Epidemiol 1996;25: 821-8.[Abstract/Free Full Text]
4. McGhee SM, Adab P, Hedley AJ, Lam TH, Ho LM, Fielding R, et al. Passive smoking at work: the short term cost. J Epidemiol Community Health 2000;54: 673-6.[Abstract/Free Full Text]
5. McGhee SM, Hedley AJ, Ho LM. Passive smoking and its impact on employers and employees in Hong Kong. Occup Environ Med 2002;59: 842-6.[Abstract/Free Full Text]

Related Article

Environmental tobacco smoke and tobacco related mortality in a prospective study of Californians, 1960-98

James E Enstrom and Geoffrey C Kabat
BMJ 2003 326: 1057. [Abstract] [Full Text] [PDF]