Association of vaping-related lung injuries with rates of e-cigarette and cannabis use across US states.

Background And Aims: Responses to the 2019 US outbreak of 'e-cigarette or vaping product use-associated lung injury' (EVALI) ranged from temporary restrictions on nicotine e-cigarette sales to critiques of state cannabis policies. However, if either mass-marketed nicotine e-cigarettes or cannabis use per se drove this outbreak, as opposed to an additive in regionally available black-market e-liquids, states' rates of vaping and/or cannabis use should predict their EVALI prevalence. This study tests that relationship.

Design: Observational study of EVALI data from US states' health departments SETTING: United States.

Participants: All US states (n = 50).

Measurements: The outcome of interest was each state's total EVALI cases per 12-64-year-old resident-an age group covering most EVALI patients-as reported in the second week of January 2020. Predictors are 2017-18 rates of adult e-cigarette use and past-month cannabis use by state.

Findings: The average state EVALI prevalence was 1.4 cases per 100 000 12-64-year-olds. Maps suggest a high-prevalence cluster comprising seven contiguous states in the northern Midwest. EVALI cases per capita were negatively associated with rates of vaping and past-month cannabis use, with the preferred specification's coefficients at -0.239 [95% confidence interval (CI) = -0.441, -0.037; P = 0.02] and -0.086 (95% CI = -0.141, -0.031; P = 0.003), respectively. Robustness checks supported this finding.

Conclusions: In the United States, states with higher rates of e-cigarette and cannabis use prior to the 2019 'e-cigarette or vaping product use-associated lung injury' (EVALI) outbreak had lower EVALI prevalence. These results suggest that EVALI cases did not arise from e-cigarette or cannabis use per se, but rather from locally distributed e-liquids or additives most prevalent in the affected areas.