Smoking and quality of life among female survivors of breast, colorectal and endometrial cancers in a prospective cohort study

Purpose: To examine the association of smoking and quality of life (QOL) among survivors of breast, colorectal, or endometrial cancers. Methods: The study included women who joined the Iowa Women's Health Study in 1986 and were subsequently diagnosed with breast, colorectal, or endometrial cancers through 2004 (n=1920). Smoking status was reported at baseline and in 2004; QOL was assessed in 2004 using the Medical Outcomes Study Short Form-36. Multivariate-adjusted odds ratios were calculated to examine the associations of smoking status and poor QOL (score lower than one-half a standard deviation below the mean of the non-smokers). Results: Compared with non-smokers, persistent smokers had higher likelihood of reporting poor Physical Functioning (odds ratio [OR] = 2.40, 95% confidence interval [CI] = 1.32-4.37), Mental Health (OR = 1.92, CI = 1.09-3.40), and Role Emotional (OR = 2.01, CI = 1.10-3.66), whereas former smokers had higher likelihood of reporting poor Physical Functioning (OR = 1.65, CI = 1.10-2.45), Mental Health (OR = 1.62, CI = 1.11-2.37), and General Health (OR = 1.51, CI = 1.03-2.21). A statistically significant trend toward higher likelihood of poor QOL was observed across smoking groups in Vitality, Physical Functioning, Mental Health, and Role Emotional. Further adjustment for physical activity resulted in attenuation of the odds ratios and p-values for trend. Conclusion: Among women with breast, colorectal, or endometrial cancers, smokers were more likely than former or non-smokers to have poor QOL. Physical activity explained, in part, the association between smoking status and QOL in our study.