Sex/gender differences in smoking cessation: A review.

Data from treatment studies tends to show women are less likely to quit smoking than men, but these findings have been disputed, typically based on contradictory evidence from epidemiological investigations. The purpose of this review was to shed light on this conflict. We conducted a qualitative review in January 2016 to examine sources of variation in sex/gender differences for smoking cessation. We identified 214 sex/gender difference tests from 190 studies through Medline and studies were categorized into efficacy trials (k=37), effectiveness trials (k=77), prospective observational studies of cessation (k=40; current smokers transitioning to former smokers), prospective observational studies of relapse (k=6; former smokers transitioning to current smokers), cross-sectional investigations of former smoker prevalence (k=32), and community-based interventions (k=4). We also summarized evidence across time periods, countries, outcome assessments, study sample, and treatment. Evidence from efficacy and effectiveness trials, as well as prospective observational studies of relapse, demonstrated that women have more difficulty maintaining long-term abstinence than men. Findings from prospective observational studies and cross-sectional investigations were mixed and demonstrated that bio-psycho-social variation in samples across place and time may determine whether or not women or men are less likely to quit smoking. Based on these findings, we consider whether sex/gender differences in quitting meet criteria for a disparity and outline directions for further research.