A Systematic Review of Loneliness and Smoking: Small Effects, Big Implications.

Background: Research supports an association between smoking and negative affect. Loneliness is a negative affective state experienced when a person perceives themselves as socially isolated and is associated with poor health behaviors and increased morbidity and early mortality. Objectives: In this article, we systematically review the literature on loneliness and smoking and suggest potential theoretical and methodological implications. Methods: PubMed and PsycINFO were systematically searched for articles that assessed the statistical association between loneliness and smoking. Articles that met study inclusion criteria were reviewed. Results: Twenty-five studies met inclusion criteria. Ten studies were conducted with nationally representative samples. Twelve studies assessed loneliness using a version of the UCLA Loneliness Scale and nine used a one-item measure of loneliness. Seventeen studies assessed smoking with a binary smoking status variable. Fourteen of the studies were conducted with adults and 11 with adolescents. Half of the reviewed studies reported a statistically significant association between loneliness and smoking. Of the studies with significant results, all but one study found that higher loneliness scores were associated with being a smoker. Conclusions/Importance: Loneliness and smoking are likely associated, however, half of the studies reviewed did not report significant associations. Studies conducted with larger sample sizes, such as those that used nationally representative samples, were more likely to have statistically significant findings. Future studies should focus on using large, longitudinal cohorts, using measures that capture different aspects of loneliness and smoking, and exploring mediators and moderators of the association between loneliness and smoking. [ABSTRACT FROM AUTHOR]