Data were collected as part of a longitudinal study examining racial/ethnic differences in smoking cessation. All participants received treatment that consisted of self-help materials, counseling, and nicotine patch therapy. Participants were recruited from the community via a free weekly advertising circular. The study was conducted in Houston TX between March 2005 and November 2007. This study was approved by the University of Texas MD Anderson Cancer Center IRB.
The current study analyses were conducted in April 2010. All participants gave signed informed consent in person before beginning the study. Full study procedures are described elsewhere.15–18
Analyses included 389 participants with complete data on demographics, race/ethnicity, and depressive symptoms at baseline. Demographics included age, gender, partner status, education, and employment status. Nicotine dependence indicators included minutes lapsed after waking before smoking the first cigarette of the day and average number of cigarettes per day.
Race/ethnicity was self-reported by study participants. In the U.S., race/ethnicity categories are typically defined as follows:19
, people having origins in any of the original peoples of Europe, the Middle East, or North Africa; black
or African American
, people having origins in any of the black racial groups of Africa; and Hispanic/Latino
, people of Cuban, Mexican, Puerto Rican, South or Central American origin, or other Spanish culture or origin, regardless of race.
Depressive symptoms were assessed with the Center for Epidemiologic Studies–Depression (CES-D) scale.20
The CES-D is a 20-item scale designed to assess symptoms of depression in the general population. Participants rate how often they experienced depressive symptoms during the past week from rarely or none of the time
to most or all of the time
. The full scale is available in the original validation study.20
Continuous abstinence across Weeks 1, 2, and 4 post-quit was the outcome variable and was assessed by a self-report of not smoking since quit day and confirmed via a carbon monoxide reading of <10 parts per million. Follow-up rates were 81.3% for Week 1 post-quit date 1, 83.9% for Week 2, and 85.7% for Week 4. An intent-to-treat procedure was followed, whereby those lost to follow-up were considered not abstinent.
The main effects of race/ethnicity and CES-D scores and their interaction were examined on abstinence across time. Analyses used continuation ratio logit modeling, which models the conditional probability of being abstinent at the current assessment point, given one has been abstinent through the most recent assessment.21–24
CES-D score was entered as a continuous variable. Covariates included each of the demographic and dependence indicators shown in .
Participant characteristics, M (SD) unless otherwise indicated