Project 3, Study 2: Extended Exposure to Low Nicotine Content Cigarettes in People With Current Affective Disorders

Overview

This study will examine extended exposure to cigarettes varying in nicotine content among disadvantaged women. Adults with affective disorders are at increased risk for smoking, nicotine dependence, and using high nicotine yield cigarettes and are also at significantly increased risk for smoking-related adverse health consequences, including site-specific cancers, heart disease, and premature death. Studies testing an innovative regulatory strategy of reducing the nicotine content of cigarettes to a non-addictive level have shown promising beneficial effects (decreased smoking rate, reduced toxicant exposure, and increased cessation) in the general population of smokers. However, these studies have uniformly excluded vulnerable populations like those with affective disorders who may respond differently considering their greater vulnerability to smoking and nicotine dependence. Thus, little is known scientifically about how this highly vulnerable subgroup of smokers might respond to a nicotine reduction policy. This project is designed to address that substantial knowledge gap. This same study was also conducted in two additional vulnerable populations under a similar protocol.

The primary overall objective of these studies is to evaluate the effects of extended exposure to cigarettes differing in nicotine content in adult men and women with affective disorders using a 3-condition, parallel groups design. After a baseline period in which daily smoking rate and other baseline assessments are completed, participants will be randomly assigned to one of three cigarette conditions (nicotine content: 0.03, 0.12, and 0.8 mg nicotine of tobacco) for the 12-week experimental period. The cigarettes to be used in this study were made under an NIH contract with production being overseen by the Research Triangle Institute (referred to as "Spectrum cigarettes"). NIH currently has approximately 10 million of these cigarettes (of varying types) for research purposes. The cigarettes selected for the study span the range of yields likely to produce the hypothesized effects, as described above. The Spectrum cigarettes are not currently commercially available, although they are similar in many ways to marketed cigarettes (e.g., similar manufacturing, filter, paper, etc.). The primary overall objective of this study is to evaluate the effects of extended exposure to cigarettes differing in nicotine content in adult men and women with affective disorders using a 3-condition, parallel groups design. After a baseline period in which daily smoking rate and other baseline assessments are completed, participants will be randomly assigned to one of three cigarette conditions (nicotine content: 0.03 mg, 0.12 mg, and 0.8 mg nicotine of tobacco) for the 12-week experimental period. Participants will be seen weekly throughout the 12-week experimental period to obtain research cigarettes. Cigarettes smoked per day will be obtained by participants completing daily Interactive Voice Response (IVR) reports of cigarettes in past 24 hours. This daily data will be used to calculate weekly means, with week-12 means serving as the primary outcome. This same study was conducted in two additional vulnerable populations under a similar protocol, with differences between protocols consisting of data collection specific to that vulnerable population. This included information such as use and timing of opioid maintenance therapy for individuals with opioid-use disorder and other measures relevant to disadvantaged women of reproductive age. In order to explore potential differences across individuals with different vulnerabilities, data from all three studies were combined for analysis. A vulnerable population-by-condition or population-by-condition-by-time interaction term was included in all analyses. In the event that these interaction terms were statistically significant, all pairwise comparisons were conducted using a Bonferroni multiple comparison adjustment.