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

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.

Smoking, drinking and colorectal cancer in Hong Kong Chinese: A case‐control study

“…6,7 Second, the prevalence of cigarette smoking reached its peak in Hong Kong about 20 years earlier than it did in mainland China. 9 This may explain why, unlike the present study, a recent report conducted in mainland China on tobacco-related mortality failed to identify any association with colorectal cancer. 8 Furthermore, the apparent long induction period of cigarettes mandates the assessment of lifelong exposure, which was not uniformly performed in previous studies.…”

“…9 This may account for the null studies that were conducted earlier in the smoking epidemics during which the extent of cigarette exposure was not sufficient to demonstrate an association with colorectal cancer in the study population. 6,7 Second, the prevalence of cigarette smoking reached its peak in Hong Kong about 20 years earlier than it did in mainland China.…”

“…5 The relationship between cigarette smoking and colorectal cancer in Chinese had previously been reported in 3 case-control studies and 1 cohort study. Two of the case-control studies, one on Singapore Chinese and another on northern Chinese, 6,7 were conducted more than a decade ago, whereas the other 2 studies, a cohort study from Shanghai and a case-control study on adult deaths in Hong Kong,8,9 were reported in 1997 and 2001, respectively. In all 4 studies, no association could be found between cigarette smoking and colorectal cancer.…”

Limited impact of tuberculosis control in Hong Kong: attributable to high risks of reactivation disease

“…Several factors could have contributed to high reactivation risks in Hong Kong compared to the United Kingdom : nutrition (likely to have been unsatisfactory in Hong Kong prior to 1950) ; smoking (peaked during the 1970s in Hong Kong compared the 1950s in the United Kingdom and Western populations, although the overall consumption was similar in the two settings [21][22][23]) ; genetics (if tuberculosis arrived recently in South East Asia, then the prevalence of susceptibility genes for tuberculosis disease may still be high [24]) ; predisposing co-infections or environmental conditions (e.g. silicosis, which is a strong risk factor for tuberculosis [25], was the second most commonly notified occupational disease during the 1990s in Hong Kong [26]) ; or the pathogen itself (most of the isolates of M. tuberculosis found among Asian tuberculosis cases belonged to the Beijing family of strains [27,28], although its association with the risks of developing disease remains unclear).…”

Tobacco use and cancer: an epidemiologic perspective for geneticists

“…Peto and others attribute this difference to the more recent initiation of serious smoking, since the main increase in cigarette smoking occurred 40 years later in China than in the USA (Liu et al, 1998;Niu et al, 1998). However, the relative risk of lung cancer ranges between 3 and 5 among middle-aged women and men in the largely (95%) Chinese population of Hong Kong, where cigarette smoking prevalence reached its peak about 20 years earlier than in mainland China (Lam et al, 2001). There is some evidence that differences in nicotine metabolism may contribute to differences in the intensity of smoking between Caucasians and Orientals.…”