Background: Obesity remains a major public health problem and a risk factor for developing chronic diseases. Substance use such as e-cigarette, marijuana, and alcohol have been associated with the risk of being obese. However, the results from previous studies have been inconsistent. The purpose of this study is to determine the association between substance use and obesity among adults in the United States.

Method: Data from the 2016 Behavioral Risk Factor Surveillance System (BRFSS), an annual cross-sectional survey administered to 446,687 adults in all 50 states to collect information about their health-related risk behaviors, chronic health conditions and the use of preventive services, was used in this study. Data was collected via a self-reported questionnaire validated by CDC. A multiple logistic regression model was conducted to determine the association between exposure variables (e-cigarette, marijuana, and alcohol abuse) and obesity. The model was adjusted for possible confounders such as demographics (age, sex and race) and behaviors such as tobacco smoking and physical activity. The data was analyzed using SAS v 9.4.

Results: Individuals who used marijuana during the past 30 days were 32.4% less likely (adjusted odds ratio (aOR): 0.676, 95% CI: 0.631-0.723, P<0.001) to be obese compared to those who did not. The odds of being obese among heavy alcohol drinkers was 30% less (aOR: 0.70, 95% CI: 0.679-0.721, p<0.001) compared to those who were not heavy alcohol drinkers.

Conclusion: The study findings demonstrate that marijuana and heavy alcohol drinking are significantly associated with reduced likelihood of obesity. However, e-cigarette use was not significantly associated with obesity. Further longitudinal studies to explore the relationship between these substances and obesity will be beneficial.