Regular Marijuana Use Associated With Reduced BMI, Says Study
Marijuana use over time is inversely related to obesity, according to a new study published in the International Journal of Epidemiology.
For the study researchers assessed the relationship between cannabis use and body mass index (BMI) over time in a nationally representative sample of 33,000 subjects.
Investigators reported that cannabis-using subgroups exhibited “appreciably attenuated BMI gain” over the trial period as compared to non-users and quitters, “with the largest attenuation seen in the ‘persistent use’ group.”
They concluded: “This new prospective study builds from anecdotes, pre-clinical studies and cross-sectional evidence on inverse associations linking cannabis use and obesity and shows an inverse cannabis–BMI increase association. Confirmatory studies with rigorous cannabis and BMI assays will be needed.”
The full abstract of the study states:
Pre-clinical studies indicate increased food intake and weight gain as cannabinoid effects. Cross-sectional epidemiological studies, however, indicate lower prevalence of obesity among cannabis users. Here, we aim to study the weight-gain research question in the prospectively conducted National Epidemiologic Survey on Alcohol and Related Conditions (NESARC).
NESARC was designed to produce nationally representative estimates for the US population. Participants (aged 18+) completed computer-assisted personal interviews on cannabis use, body weight and height at Waves 1 (W1, 2001–02) and 2 (W2, 2004–05). General linear modelling yields estimates for change in body mass index (BMI) regressed on cannabis-use status, with covariate adjustment based on a conceptual model for BMI determinants (n = 33 000).
At W2, 77% of the participants never used cannabis, 18% had discontinued use (‘quit’), 3% were initiates and 2% were persistent users. Estimated W1-to-W2 BMI change shows an increase for all subgroups. Compared with never-users (reference), inverse slope estimates and attenuated change (%) in BMI between W1 and W2 are seen for cannabis-use subgroups: quitters [β = –0.81; 95% confidence interval (CI) = –1.01, –0.60], initiates (β = –0.97; 95% CI = –1.36, –0.57) and persistent users (β = –1.26; 95% CI = –1.81, –0.72).
This new prospective study builds from anecdotes, pre-clinical studies and cross-sectional evidence on inverse associations linking cannabis use and obesity and shows an inverse cannabis–BMI increase association. Confirmatory studies with rigorous cannabis and BMI assays will be needed.
The results are similar to a study released earlier this year. That study, titled Associations between cannabis use and cardiometabolic risk factors: A longitudinal study of men, “tested longitudinal associations between cannabis use and cardiometabolic risk factors that underlie the development of cardiovascular diseases.”
Participants were men from the youngest cohort of the Pittsburgh Youth Study who were followed prospectively from approximately age 7 to 32. Frequency of cannabis use was assessed yearly from ~ages 12-20 and again at ~ages 26, 29, and 32. The following cardiometabolic risk factors were assessed during a laboratory visit at age ~32: “BMI, WHR, HDL and LDL cholesterol, triglycerides, fasting glucose, HOMA-IR, blood pressure, interleukin 6, and C-reactive protein.”
Researchers found that “Greater cannabis exposure was associated with relatively lower BMI, smaller WHR, better HDL and LDL cholesterol, lower triglycerides, lower fasting glucose and HOMA-IR, lower systolic and diastolic blood pressure, and fewer metabolic syndrome criteria.”
With exception of BMI, “cannabis users’ mean levels on cardiometabolic risk factors were generally below clinical cutoffs for high risk. Most associations between cannabis use and cardiometabolic risk factors remained after adjusting for tobacco use, childhood SES, and childhood health.”
However, after adjusting for adult BMI, “these associations were no longer apparent, and mediation tests suggested that cannabis users’ relatively lower BMI might explain their lower levels of risk on other cardiometabolic risk factors.”
Researchers conclude; “Cannabis use is associated with lower BMI, and lower BMI is related to lower levels of risk on other cardiometabolic risk factors.”
For more info on this study, click here.