E-cigarette use linked to depression

Electronic cigarette (e-cigarette) use has been shown to increase the risk of depression in a recent cross-sectional study in adults in the United States.

Former e-cigarette users were 1.6 times more likely to self-report a history of clinical diagnosis of depression (95 percent CI [confidence interval], 1.54 to 1.67) than never users, whilst current users had a 2.10-fold increase in risk (95 percent CI, 1.98 to 2.23). Likewise, daily e-cigarette users were at a higher risk of depression compared with those who used e-cigarettes occasionally (odds ratio [OR], 2.39 vs 1.96; 95 percent CI, 2.19 to 2.61 vs 1.82 to 2.10). [JAMA Netw Open 2019;2:e1916800]

Statistically significant interactions were found in subgroup analyses between e-cigarette use and age (OR per increase in age category, 0.97; 95 percent CI, 0.96 to 0.97; p<0.001), sex (women vs men: OR, 1.13; 95 percent CI, 1.08 to 1.18; p<0.001) and race/ethnicity (white individuals vs individuals of other races/ethnicities: OR, 1.07; 95 percent CI, 1.04 to 109; P<0.001).

In this cross-sectional study using data from the Behaviour Risk Factor Surveillance System database, the participants’ e-cigarette use and self-reported history of depression and mental health were analysed. Among 892,324 participants, 28,736 were current e-cigarette users, of whom 13,071 were aged 18–39 years. Current e-cigarette users were more likely to be single (48.4 percent vs 24.3 percent), male (60.1 percent vs 46.6 percent), <40 years of age (62.1 percent vs 32.2 percent), and current combustible cigarette smokers (51.8 percent vs 7.9 percent) compared with never e-cigarette users.

Though e-cigarettes are marketed as less harmful nicotine delivery devices, their contents are largely unregulated, often containing potentially toxic metals. When in use, they may generate volatile organic compounds, especially at high temperatures. In the US, more than half of the e-cigarette users were younger than 35 years of age in 2016. At the same time, individuals with mental health problems are more likely to smoke heavily and find it harder to quit smoking. [Ann N Y Acad Sci 2015;1340:65-74; Int J Environ Res Public Health 2016;14.pii: E10; BMJ 2015;351:h4065]

“Results of our study may have potential implications for regulation of e-cigarettes and also highlight the need for prospective longitudinal studies to investigate the risk of depression associated with e-cigarette use,” concluded the authors.