Associations of mental illness with smoking and vaping in university students in New Zealand

Abstract

Abstract Background People with mental illness have higher smoking prevalence, and vaping is generally higher among smokers than non-smokers. However, data on associations of mental illness with smoking and vaping in New Zealand (NZ) is lacking. This study examines associations of history of mental illness (HMI) with smoking and vaping in NZ university students. Methods Data came from a March 2018 national cross-sectional study. χ2 tests compared patterns of smoking and vaping in students with and without HMI. An HMI was defined as a diagnosis, or treatment for depression, anxiety or nervous disorder, or other mental health condition in the previous 12 months. Logistic regression model assessed the association of an HMI with smoking and vaping. Results 1622 students were included: 82.7% aged <25 years, 17.3% ≥25 years; 38.6% male, 61.4% female; 7.8% Māori, 92.2% non-Māori; 18.1% reported an HMI. Of respondents, 50.5% (95% CI 48.0-53.0) reported ever, 10.0% (8.6-11.6) current and 5.0% (4.0-6.2) daily smoking. Students with HMI were significantly more likely to report ever (p<.001), current (p=.008) and daily smoking (p=.014) than those without HMI. 36.7% (34.3-39.1) of students reported ever, 6.7% (5.5-8.0) current and 2.5% (1.8-3.4) daily vaping. Students with HMI were significantly more likely to report ever (p<.001), current (p=.002) and daily vaping (p=.022) than those without HMI. The full model containing all predictors was statistically significant, χ2 (5, N = 1621) = 34.843, p < .001. Female gender: OR 0.55 (0.41-0.73); current smoking: OR 1.76 (1.19-2.60), and current vaping: OR 2.07 (1.32-3.25) were significantly associated with an HMI. Conclusions There were strong associations between an HMI and smoking and vaping (controlling for age, gender, ethnicity). These findings extend earlier work on the relationship between smoking and mental illness by demonstrating similar associations in university students, and generate new information on HMI and vaping. Key messages Significant numbers of students may have an HMI. Students with an HMI have higher prevalence of smoking and vaping than students without an HMI.