Increases in endogenous progesterone attenuate smoking in a cohort of nontreatment seeking women: An exploratory prospective study.

Despite advances in prevention and treatment, cigarette smoking remains a leading cause of preventable death in the United States. Although men and women are equally likely to attempt to quit smoking cigarettes, women are far less likely to achieve abstinence both during and following cessation treatment. Recent evidence suggests that ovarian hormone levels may play a role in successful abstinence attempts in women smokers. The primary goal of this exploratory prospective observational study was to estimate the association between within-participant levels of progesterone and estradiol with associated cigarettes smoked per day in adult women smokers (n = 104). The primary study outcome was self-reported cigarettes smoked per day (CPD) during a 2-week observational period collected using a daily smoking diary. Additionally, participants collected saliva daily, from which hormone levels (progesterone and estradiol) were derived. Higher within-participant progesterone levels were associated with a significant decrease in CPD (p = .008) whereas within-participant estradiol levels were unrelated to CPD (p = .25). Regression models indicated a single change in the trajectory of smoking behavior for both within-participant progesterone and estradiol. When progesterone values were below the change point, there was a significant inverse relationship between within-participant progesterone levels and smoking behavior (p = .025) whereas the relationship was attenuated for higher within-participant progesterone levels (p = .59). The effect of estradiol on smoking behavior was not significant when it was either below (p = .92) or above (p = .16) the change point. Higher within-participant levels of progesterone but not estradiol are associated with reduced CPD in nontreatment seeking women smokers.