Clarke E A, Morgan R W, Newman A M
Am J Epidemiol. 1982 Jan;115(1):59-66. doi: 10.1093/oxfordjournals.aje.a113279.
The results of a case-control study in Toronto, Canada, demonstrated a two-fold risk of invasive squamous cell carcinoma of the cervix among current smokers relative to women who had never smoked. This significant effect of smoking was not diminished by simultaneously adjusting for age, education, and indices of sexual behavior. This association was further supported by the observations that ex-smokers were at a lower risk than current smokers (1.7 versus 2.3), and that the risk increased with the amount of cigarettes smoked (2.2 for less than half a pack per day to 2.9 for more than one pack per day).
加拿大多伦多一项病例对照研究的结果表明，与从未吸烟的女性相比，当前吸烟者患宫颈浸润性鳞状细胞癌的风险高出两倍。同时对年龄、教育程度和性行为指标进行调整后，吸烟的这一显著影响并未减弱。既往吸烟者的风险低于当前吸烟者（分别为1.7和2.3），且风险随吸烟量增加而上升（每天少于半包者为2.2，每天多于一包者为2.9），这些观察结果进一步支持了这一关联。
