Objectives: We studied the association between cigarette smoking and ovaria
n cancer in a population-based case-control study.
Methods: A total of 794 women with histologically confirmed epithelial ovar
ian cancer who were aged 18-79 years and resident in one of three Australia
n states were interviewed, together with 855 controls aged 18-79 years sele
cted at random from the electoral roll from the same states. Information wa
s obtained about cigarette smoking and other factors including age, parity,
oral contraceptive use, and reproductive factors. We estimated the relativ
e risk of ovarian cancer associated with cigarette smoking, accounting for
histologic type, using multivariable logistic regression to adjust for conf
ounding factors.
Results: Women who had ever smoked cigarettes were more likely to develop o
varian cancer than women who had never smoked (adjusted odds ratio (OR) = 1
.5; 95% confidence interval (CI) = 1.2-1.9). Risk was greater for ovarian c
ancers of borderline malignancy (OR = 2.4; 95% CI = 1.4-4.1) than for invas
ive tumors (OR = 1.7; 95% CI = 1.2-2.4) and the histologic subtype most str
ongly associated overall was the mucinous subtype among both current smoker
s (OR = 3.2; 95% CI = 1.8-5.7) and past smokers (OR = 2.3; 95% CI = 1.3-3.9
).
Conclusions: These data extend recent findings and suggest that cigarette s
moking is a risk factor for ovarian cancer, especially mucinous and borderl
ine mucinous types. From a public health viewpoint, this is one of the few
reports of a potentially avoidable risk factor for ovarian cancer.