Effects of active, passive, and combined smoking on cervical cancer mortality: a nationwide proportional mortality study in Chinese urban women.

Purpose: To determine whether smoking, in any form, is a risk factor in the development of cervical cancer (CC) among urban Chinese women.

Methods: We ascertained retrospectively the smoking habits of 1,865 women (aged 35+) who had died from CC (cases) and 48,781 who had died from causes unrelated to smoking (controls) in 24 cities using data from a large national survey of smoking and mortality in 1989-1991. We assessed the risk of smoking on CC mortality with and without considering passive smoke exposure from a spouse using a proportional mortality study design.

Results: Overall, there was a 51.0 % excess risk of death from CC among smokers. When the spouse's exposure was further considered, the RR (95 % CI) for exposed versus unexposed women was 1.28 (1.04-1.57) for passive smokers, 1.49 (1.02-2.20) for active smokers, and 1.69 (1.27-2.26) for women with both exposures (all p < 0.001). Significant dose-response associations were observed between smoking and CC for all categories of exposure. For example, individuals with both smoking exposure had the highest risk of CC mortality with moderate [RR = 1.67 (1.18-2.38)] and high [RR = 1.88 (1.04-3.41)] daily cigarette consumption, and they also had the highest risk with ≤15 years exposure [RR = 1.73 (1.19-2.52)] and >15 years exposure [RR = 1.95 (1.15-3.32)], compared with the active and passive groups (p for trend <0.001).

Conclusions: Younger trend of CC death and the rapid increase in smoking among young women may have a profound impact on future incidence of CC. Our findings emphasize the need for preventive efforts among both women and men in China.