Smoking and lung cancer in women: findings in a prospective study.

Lung cancer rates in relation to smoking habits were studied in a cohort of 619,225 women traced over a 4-yr period (1982 to 1986). A total of 1,006 lung cancer deaths was recorded. The standardized mortality ratio (SMR) for women smokers was 12.7 for current smokers and 4.8 for exsmokers. For those women without a history of chronic diseases, the SMR rose to 17.6 for current smokers. The SMRs rose with the number of cigarettes smoked per day to 22.0 for women who smoked 31 or more per day. SMRs also increased with depth of inhalation; this increase was independent of the number smoked per day. SMRs also increased by duration of smoking and decreased with cessation of smoking. Mortality ratios for lung cancer in women ranged from about 2 to 1 to 3 to 1 in studies carried out in the 1950s and 1960s. As women have begun to smoke earlier in life, smoke more cigarettes a day, and inhale more deeply, we are now observing much higher SMRs in women with lung cancer, similar in magnitude to those seen in men in the earlier studies.