Bidirectional Longitudinal Associations Between Cannabis Use and Body Mass Index Among Adolescents.

Introduction: Literature on the association between cannabis use and body mass index (BMI) among adults suggests that greater cannabis use is associated with a lower BMI. However, results are mixed among adolescents, with both cross-sectional and longitudinal studies finding positive, negative, and nonsignificant associations between cannabis use and BMI. This longitudinal study aims to shed light on these associations by prospectively examining the associations between cannabis use and BMI across a 2-year window in a large sample of adolescent cannabis users. Methods: Participants were 401 adolescents ages 14-17 at baseline who were at risk for escalation in their use of cannabis. We conducted a parallel process latent growth curve model to examine associations between the cannabis use intercept, BMI intercept, cannabis use slope, and BMI slope. Results: Results showed that baseline BMI predicted a positive and significant association with cannabis use slope. In addition, there was a significant and negative correlation between the cannabis use slope and the BMI slope. These significant associations remained after controlling for relevant covariates. Conclusions: Results are consistent with the adult literature that reports a negative association between cannabis use and BMI. Future research should focus on uncovering the mechanisms that may drive the association between cannabis use and BMI.