Morbidity and mortality in relation to smoking among women and men of Chinese ethnicity: the Singapore Chinese Health Study.
OBJECTIVE
We examined the association among cigarette smoking, smoking cessation and a broad range of cancer incidence and all cause and cause-specific mortality in a population-based cohort of adults of Chinese ethnicity in Singapore.


METHODS
Subjects were 61,320 participants of the Singapore Chinese Health Study (44.5% men, aged 45-74 years, recruitment from 1993-1998) who were free of cancer at the baseline examination. Main outcomes-of-interest included cancer incidence, all cause and cause-specific mortality as of December 31, 2005.


RESULTS
Cigarette smoking was positively associated with overall cancer incidence, including cancers at the following specific sites: head and neck region, upper gastrointestinal tract, hepatobiliary and pancreas cancer, lung, and bladder/renal pelvis cancer. Compared to never smokers, the relative risk (RR) (95% confidence interval [CI]) of cancer incidence (all cancer sites) among current smokers smoking >22 cigarettes/day was 1.9 (1.7-2.1), p-trend<0.0001. Similarly, cigarette smoking was associated with all cause and cause-specific mortality, including deaths due to cancer, ischemic heart disease, other heart diseases, and chronic obstructive pulmonary disease. Compared to never smokers, RR (95%CI) of all cause mortality among current smokers smoking >22 cigarettes/day was 1.8 (1.6-2.0), p-trend<0.0001. Also, relative to current smokers, ex-smokers experienced reduced cancer incidence and total mortality. The population attributable risk of smoking in men for cancer incidence as well as all-cause mortality was 23%, whereas in women it ranged from 4-5%.


CONCLUSIONS
Cigarette smoking is an important risk factor for cancer incidence and major causes of mortality in Chinese men and women of Singapore.
Shankar
Anoop
A
Department of Community, Occupational, and Family Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. ashankar@nus.edu.sg
Yuan
Jian-Min
JM
Koh
Woon-Puay
WP
Lee
Hin-Peng
HP
Yu
Mimi C
MC
D000368:Aged; D002681:China / Q000208:ethnology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000208:ethnology / Q000209:etiology / Q000401:mortality*; D012307:Risk Factors; D012846:Singapore / Q000453:epidemiology; D012907:Smoking / Q000208:ethnology / Q000401:mortality*; D016540:Smoking Cessation / Q000208:ethnology / Q000706:statistics & numerical data