Do ethnicity and gender moderate the influence of posttraumatic stress disorder on time to smoking lapse?

Highlights

• Black ethnicity significantly moderated the effect of PTSD on time to first smoking lapse.

• PTSD significantly predicted time to smoking lapse for White smokers only.

• White smokers without PTSD lapsed at a slower rate compared to all other participants.

• Socioeconomic status predicted rate of smoking lapse independent of ethnicity.

Abstract

Background

Following a smoking cessation attempt, smokers with posttraumatic stress disorder (PTSD) experience smoking relapse at a higher and faster rate. Black ethnicity and female gender are also associated with lower success rates following smoking cessation. No study to date has prospectively examined how ethnicity and gender may moderate the effect of PTSD on smoking relapse. It was hypothesized that female gender and Black ethnicity would significantly predict early lapse after quitting; further, it was predicted that ethnicity and gender would moderate the effect of PTSD on relapse rate.

Methods

Smokers with PTSD (n = 48) and without PTSD (n = 56) completed ecological momentary assessment (EMA) the week after a quit date, and self-initiated EMA entries after smoking lapse. Smoking abstinence was biologically verified. The sample included Black (62%) and White (38%) participants, and was 50% female. Study hypotheses were tested with Cox proportional hazards regression modeling time to first smoking lapse.

Results

Study results confirmed the main hypothesis, with a significant PTSD × Ethnicity interaction emerging. The effect of PTSD on smoking relapse was significant for White participants but not for Black participants. No significant gender moderation was found.

Conclusion

Taken together, study results support previous research, and suggest that the relationship between smoking and PTSD is stronger for White smokers than for minorities. This study has significant implications for research in smoking and mental disease, as well as for smoking cessation treatments for Black smokers.

Introduction

Posttraumatic stress disorder (PTSD) presents a significant barrier to smoking cessation in the general population (Hapke et al., 2005). Around 45% of individuals with PTSD are current smokers, and PTSD is associated with an increased likelihood of being a smoker (Feldner, Babson, & Zvolensky, 2007). Evidence suggests that smoking increases the risk of developing PTSD (Breslau et al., 2004, Koenen et al., 2005). Moreover, PTSD smokers are less able to quit smoking and have a shorter time to first smoking lapse within the first week of a quit attempt (Zvolensky et al., 2008). It is theorized that core features of PTSD, including trauma symptoms and increased negative affect, represent key risk factors for smoking lapse and relapse (Beckham et al., 2013, Beckham et al., 2007, Cook et al., 2007). Additionally, individuals with PTSD experience more intense withdrawal symptoms during smoking cessation, which could also increase the risk for smoking relapse (Dedert et al., 2012). Since smoking is related to PTSD symptoms and PTSD symptoms can in turn increase the risk for smoking relapse, it is essential to further investigate early lapse in PTSD smokers.

Rates of smoking relapse within the general population are also affected by gender and ethnicity (Japuntich et al., 2011). In a large-scale clinical trial testing the efficacy and effectiveness of different types of smoking cessation treatment, both females (compared to males) and Black smokers (compared to White smokers) were more likely to relapse following a quit attempt, largely regardless of treatment used (Piper et al., 2010). It is theorized that ethnic and gender differences in nicotine metabolism (Hukkanen, Jacob, & Benowitz, 2005) – possibly related in part to genetic polymorphism of the CYP2A6 gene (Derby et al., 2008) – significantly contribute to increased susceptibility of smoking relapse. Specifically, females may be more highly addicted to nicotine due to their faster nicotine metabolism, which likely increases their level of dependence (Benowitz, Lessov-Schlaggar, Swan, & Jacob, 2006). In contrast, smokers of African and Asian descent generally metabolize nicotine more slowly than smokers of European descent (Nakajima et al., 2006); yet Black smokers take in significantly more nicotine per cigarette and are more highly addicted compared to White smokers (Benowitz, 2008, Perez-Stable et al., 1998). These data, taken together, suggest that women and Black smokers have increased risk for smoking lapse following a quit attempt.

In addition to main effects of ethnicity and PTSD on smoking cessation, ethnicity may moderate the effect of PTSD on smoking cessation. Differences in smoking rates between ethnicities are likely influenced by several societal and cultural factors, as well as individual differences. A nationally representative study found that for minorities (defined as Black and Hispanic respondents) there was no significant relationship between past-30-day psychological distress and current smoking status or cigarettes smoked per day. However, there was a significant association of psychological distress with smoking status in White respondents (Kiviniemi, Orom, & Giovino, 2011). While an association between general distress and smoking status has clinical relevance, it is important to determine whether the same relationship may or may not be present when considering an interaction between ethnicity and specific psychiatric diagnoses. Another nationally representative study of Black Americans found that the presence of a lifetime or current psychiatric disorder was significantly associated with current smoking status. In addition, past year and past month psychiatric disorders were significantly associated with lower odds of being at least one year abstinent (Hickman, Delucchi, & Prochaska, 2010). Existing knowledge regarding the interaction between ethnicity and psychiatric disorders is limited because previous research has relied on retrospective report and has not examined specific psychiatric disorders, such as PTSD. There is a need for research that utilizes prospective methodology to monitor post-quit lapse events as they occur.

The effects of major sociodemographic factors such as ethnicity and gender on smoking cessation in PTSD are particularly important because women and Black Americans are more likely to have PTSD, and are more likely to have difficulty quitting smoking (Benowitz, 2008, Brewin et al., 2000). As these groups are overrepresented among PTSD smokers, it is important to investigate how ethnicity and gender influence cessation behaviors in smokers with PTSD. The aim of the current study is to provide the first prospective investigation of the moderating effect of ethnicity on PTSD with regard to smoking lapse following a quit attempt. The study hypotheses were: 1) ethnicity will significantly predict lapse after quitting, with Black smokers exhibiting a faster lapse rate compared to Whites; 2) female gender will be associated with faster lapse rate; 3) ethnicity will moderate the effect of PTSD on lapse rate, such that Black smokers will exhibit a smaller effect of PTSD on lapse rate; and 4) gender will also moderate the effect of PTSD on lapse rate, such that women will have a larger effect of PTSD on lapse rate.