New School Study: Marijuana Users Have Lower Body Mass Index than Non-Users
September 20, 2016
Those who use marijuana, commonly associated with “the munchies” or increased appetite and the likelihood of weight gain, actually have a lower body mass index (BMI) than non-users, according to the results of a new study from the School’s Department of Health Sector Management and Policy and the University’s Miller School of Medicine. The findings, published in the September issue of The Journal of Mental Health Policy and Economics, shows that daily female marijuana users have a BMI that is about 3.1 percent lower than that of female non-users, and that daily male users have a BMI that is about 2.7 percent lower than male non-users. BMI is a measure of body fat based on height and weight, used to classify overweight and obesity.
Researchers controlled for several other factors that could potentially correlate with BMI. The demographic variables included age, race, ethnicity, employment status, and marital status. They also controlled for cigarette smoking, other substance use and alcohol consumption, as well as measures of weekly exercise and self-rated health status.
“Our findings run counter to popular belief which associates marijuana use with laziness and increased appetite,” said Michael T. French, PhD, professor of health sector management and policy at the School. “If marijuana use is significantly related to these physiological characteristics, you would expect a positive association with marijuana use and BMI. Our study has demonstrated the opposite,” added French, who conducted the study with lead investigator Isabelle Beulaygue, PhD, from the Miller School.
The researchers point out that the study results are correlational rather than causal and that it would be irresponsible to advocate for marijuana use as a dieting strategy. Future research could explore the metabolic and behavioral pathways underlying the negative associations between marijuana use and BMI.
Using data from the of the National Longitudinal Survey of Adolescent Health (sample size greater than 13,000 people), the researchers used econometric models to rigorously study the relationships between marijuana use and body mass index over six years vs. simply at one point in time. Their analyses included young adults over the age of 18, when the use of marijuana and other drugs ordinarily peaks. Numerous sensitivity tests and alternative estimation techniques confirmed the core findings. For example, they also investigated the relationship between marijuana use and waist circumference, an alternative measure of body size. Like with BMI, it was found that marijuana use is negatively associated with waist circumference.
The study can be found at http://www.ncbi.nlm.nih.gov/pubmed/27572145.