Association between ovarian hormones and smoking behavior in women.

Studies examining the association between menstrual cycle phases and smoking behavior in women have yielded mixed results. The purpose of this study was to elucidate the associations between ovarian hormones and smoking by directly measuring ovarian hormone levels and obtaining a laboratory assessment of smoking behaviors. Four hypotheses were tested: Increased smoking will be associated with (1) low absolute levels of estradiol and progesterone; (2) decreasing (i.e., dynamic changes in) estradiol and progesterone; (3) lower ratios of progesterone to estradiol; and (4) higher ratios of estradiol to progesterone. Female smokers (≥10 cigarettes/day) with regular menstrual cycles were recruited as part of a larger, ongoing study examining the influence of ovarian hormones on smoking cessation treatment. Participants completed 2 study visits, including a 1-hr ad lib smoking topography session, which provided a detailed assessment of smoking behavior. Both the change in hormone levels over time and the relative ratios of ovarian hormones were associated with smoking behavior, but each to a limited extent. Decreases in estradiol (r = -.21, p = .048) and decreases in progesterone (r = -.23, p = .03) were associated with increased puff intensity. Lower ratios of progesterone to estradiol were associated with a greater number of puffs (r = -.26, p = .01) and weight of cigarettes smoked (r = -.29, p = .005). The best predictors of smoking behavior were the ratio of progesterone to estradiol (z = -2.7, p = .004) and the change in estradiol and progesterone over time (z = -2.1, p = .02). This pattern of results may help to explain inconsistent findings in previous studies and suggest potential mechanisms by which hormones influence nicotine addiction.