Marijuana users have smaller waists, better blood sugar control

By Will Parker on May 16, 2013 in Medicine, News

A new study in The American Journal of Medicine has found that regular marijuana use is associated with beneficial effects related to diabetic control. The researchers showed that current marijuana users had significantly lower fasting insulin and were less likely to be insulin resistant. The findings, they stress, held true even after excluding patients with a diagnosis of diabetes mellitus.

The study took data from the U.S. National Health and Nutrition Survey between 2005 and 2010. Specifically, the researchers looked at data from 4,657 patients who completed the survey’s drug use questionnaire. Of these, 579 were current marijuana users, 1,975 had used marijuana in the past but were not current users, and 2,103 had never inhaled or ingested marijuana. Fasting insulin and glucose were measured via blood samples following a nine hour fast, and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated to evaluate insulin resistance.

Lead investigator Murray A. Mittleman said participants who reported using marijuana in the past month had lower levels of fasting insulin and HOMA-IR, and higher levels of high-density lipoprotein cholesterol (HDL-C, also known as “good” cholesterol).

Interestingly, the associations were weaker among those who reported using marijuana at least once, but not in the past thirty days, suggesting that the impact of marijuana use on insulin and insulin resistance exists during periods of recent use. Current users had 16 percent lower fasting insulin levels than participants who reported never having used marijuana in their lifetimes. Mittleman, from the Beth Israel Deaconess Medical Center in Boston, said that there were also significant associations between marijuana use and smaller waist circumferences.

“It is possible that the inverse association in fasting insulin levels and insulin resistance seen among current marijuana users could be in part due to changes in usage patterns among those with a diagnosis of diabetes (i.e., those with diabetes may have been told to cease smoking). However, after we excluded those subjects with a diagnosis of diabetes mellitus, the associations between marijuana use and insulin levels, HOMA-IR, waist circumference, and HDL-C were similar and remained statistically significant,” explained Elizabeth Penner, co-author of the study.

The new findings add to previous studies highlighting the paradox that people who smoke marijuana have higher average caloric intake levels than non-users while maintaining a lower body-mass index.

“Remarkable,” said Joseph S. Alpert, Editor-in-Chief of The American Journal of Medicineand Professor of Medicine at the University of Arizona College of Medicine, in his comments on the findings. “We desperately need a great deal more basic and clinical research into the short- and long-term effects of marijuana in a variety of clinical settings such as cancer, diabetes, and frailty of the elderly,” he said. “I would like to call on the NIH and the DEA to collaborate in developing policies to implement solid scientific investigations that would lead to information assisting physicians in the proper use and prescription of THC in its synthetic or herbal form.”