Lisa Nainggolan 16May2013
In research dubbed "remarkable" by an accompanying
editorialist, US doctors describe how current users of
marijuana appear to have better blood glucose control
than never or former users.
Existing cannabis smokers had lower levels of fasting
insulin and were less likely to be insulin resistant than
nonusers; this finding remained true even when patients
with diabetes were excluded in this large sample from the
National Health and Nutrition Survey (NHANES) between 2005
and 2010.
Marijuana users also had smaller waist circumferences and
higher levels of HDL cholesterol than never users,
Elizabeth A. Penner, from the University of Nebraska
College of Medicine, Omaha, and colleagues report in their
article published online May 16 in the American Journal
of Medicine.
"Previous epidemiologic studies have found lower prevalence
rates of obesity and diabetes mellitus in marijuana users
compared with people who have never used marijuana,
suggesting a relationship between cannabinoids and
peripheral metabolic processes," says senior author Murray
Mittleman, MD, DrPH, from Beth Israel Deaconess Medical
Center, Boston, Massachusetts, in a statement. "But ours
is the first study to investigate the relationship
between marijuana use and fasting insulin, glucose, and
insulin resistance."
In an accompanying commentary, Joseph S. Alpert, MD, from
University of Arizona College of Medicine, Tucson, who is
also editor-in-chief of the American Journal of Medicine,
wonders whether "[Tetrahydrocannabinol] THC will be
commonly prescribed in the future for patients with
diabetes or metabolic syndrome alongside antidiabetic oral
agents or insulin for improved management of this chronic
illness.
"Only time will answer this question for us," he adds.
"Nevertheless, what is very clear is that we desperately
need a great deal more basic and clinical research into the
short- and long-term effects of this agent in a variety of
clinical settings, such as cancer, diabetes, and frailty of
the elderly."
Effects Seem to Be Related to Current Use of Cannabis
Ms. Penner and colleagues studied 4657 participants of the
observational NHANES database, a nationally representative
survey of US adults, who had completed a drug-use
questionnaire.
Of these, 579 were current users (had self-reported smoking
marijuana or hashish in the past month), 1975 had smoked
marijuana in the past but were not current users, and 2103
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.
Glucose levels were lower among current users of marijuana
than never users, but this difference ceased to be
significant following multivariate adjustment. The
researchers also found no significant association between
marijuana use and triglyceride levels or systolic or
diastolic blood pressure.
But compared with those who had never used cannabis,
current users had 16% lower levels of fasting insulin and
17% lower HOMA-IR, findings that remained significant even
after multivariate adjustment. They also had 1.63-mg/dL-
higher HDL-cholesterol levels, as well as lower waist
circumferences, both of which remained significant after
adjustment.
And in an analysis also adjusting for body mass index,
which the researchers say is a potential mediator of the
link between marijuana and cardiometabolic outcomes, the
associations were attenuated but remained statistically
significant. The results were also not materially different
when participants with diabetes mellitus were excluded.
Crucially, the best results were seen in current users of
cannabis. "These associations were weaker among those who
reported using marijuana at least once, but not in the past
30 days, suggesting that the impact of marijuana use on
insulin and insulin resistance exists during periods of
recent use," Ms. Penner and colleagues observe.
These new findings "are indeed remarkable observations that
are supported, as the authors note, by basic-science
experiments that came to similar conclusions," Dr. Alpert
points out in his editorial.
Call for Much More Research Into Cannabis
With the recent legalization of medical marijuana use in
the form of THC in 19 states and the District of Columbia
and recreational use in 2 states, "physicians will
increasingly encounter marijuana use among their patient
populations," Dr. Alpert adds. There are an estimated 17.4
million current users of marijuana in the United States,
with approximately 4.6 million of these smoking it daily or
almost daily.
And although there will continue to be debate regarding
legislation and current medical use of cannabis, the real
problem is that there "a dearth of scientific,
pharmacologic, and clinical studies with this agent," he
observes, pointing out that the majority of research that
does exist looks at central nervous system effects of
marijuana and potential addictive qualities.
"I would like to call on the National Institutes of Health
and the Drug Enforcement Administration 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," he concludes.
The authors and editorialist have reported no relevant
financial relationships.
http://www.medscape.com/viewarticle/804281?nlid=31304_1049&src=wnl_edit_dail&uac=54526HK