Background and Aims: In some clinical studies men and women have been found to differ in their ability to quit smoking, perhaps as a result of progesterone. The primary aim of this study was to provide a preliminary test of whether progesterone (PRO), compared with placebo (PBO), was more effective for smoking cessation in men and women. Design: Pilot double-blind, placebo-controlled randomized clinical trial. Setting: Minneapolis/St Paul metro area, Minnesota, USA. Participants: A total of 216 participants were randomized, including 113 men (18–60 years; PRO = 56, PBO = 57) and 103 women (18–50 years, pre-menopausal with self-reported regular menstrual cycles; PRO = 51, PBO = 52). Intervention: Participants were randomized (1 : 1 within sex group) to either PRO (200 mg twice daily) or PBO. Participants were assigned a quit date approximately 7 days after starting medication (luteal phase for women) and were followed for 12 weeks to assess relapse. Measurements: The primary outcome was self-reported 7-day point prevalence abstinence (PPA) at week 4. Secondary outcomes included 7-day PPA at weeks 8 and 12, prolonged abstinence, continuous abstinence, urine cotinine < 50 ng/ml, expired carbon monoxide ≤ 5 parts per million (p.p.m.) and days to relapse. Findings: There was a significant difference in 7-day PPA at week 4 among women [PRO: 18 (35.3%) versus PBO: 9 (17.3%), odds ratio (OR) = 2.61, 95% confidence interval (CI) = 1.04, 6.54, P = 0.041], but not among men [PRO: 13 (23.2%) versus PBO: 12 (21.1%), 1.13 (0.47, 2.76), P = 0.782]. There was some evidence that PRO delayed relapse in women (days to relapse; PRO: 20.5 ± 29.6 versus PBO: 14.3 ± 26.8, P = 0.03) but not in men (PRO: 13.4 ± 25.9 versus PBO: 13.3 ± 23.8, P = 0.69). Conclusions: Oral micronized progesterone may aid smoking cessation in women.
Bibliographical noteFunding Information:
We thank Marilyn Carroll, John Grabowski and Sheila Specker for their role in conceptualizing this study. We thank Lindsay Jarvis, Ashli Carlson, Brittany Niesen and David Babb for their role in study implementation and data collection. We thank the Assay Unit at the University of Minnesota's Whiteside Institute for Clinical Research for analysis of progesterone levels. We thank Nicole M. Thomson for performing the urinary cotinine analysis in the laboratory of Dr Sharon E. Murphy at the University of Minnesota Masonic Cancer Center. We thank Frances Levin, Joy Schmitz and Paul Pentel for their role as the Data Safety and Monitoring Board. Support for this project was provided by the National Institute on Drug Abuse and Office of Research on Women's Health (P50DA033942; S.A. and M.C.). This project was also supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development grant (K12HD055887; A.A.), administered by the University of Minnesota Deborah E. Powell Center for Women's Health. Support was further provided by the National Center for Advancing Translational Sciences of the National Institutes of Health (UL1TR000114). The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
- smoking cessation