Women who used marijuana (cannabis) at least four times in the previous month (heavy users) were less likely to have type 2 diabetes than women who were light users or nonusers, in a nationally representative U.S. observational study.
In contrast, there were no differences in the prevalence of type 2 diabetes in men who were light or heavy cannabis users versus nonusers.
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These findings are based on data from the 2013-2018 National Health and Nutrition Examination Survey (NHANES), whereby participants self-reported their cannabis use.
The study by Ayobami S. Ogunsola, MD, MPH, a graduate student at Texas A&M University, College Station, and colleagues was recently published in Cannabis and Cannabinoid Research.
What do the findings mean?
Although overall findings linking cannabis use and diabetes have been inconsistent, the gender differences in the current study are consistent with animal studies and some clinical studies, senior author Ibraheem M. Karaye, MD, MPH, said in an interview.
However, these gender differences need to be confirmed, and “we strongly recommend that more biological or biochemical studies be conducted that could actually tell us the mechanisms,” said Dr. Karaye, an assistant professor in the department of population health, Hofstra University, Hempstead, N.Y.
“It’s indisputable that medical marijuana has some medical benefits,” he added. “Women [who use cannabis] have been shown to lose more weight than men, for example.”
“If women [cannabis users] are less likely to develop diabetes or more likely to express improvement of symptoms of diabetes,” he noted, “this means that hyperglycemic medications that are being prescribed should be watched scrupulously. Otherwise, there is a risk that [women] may overrespond.”
That is, Dr. Karaye continued, women “may be at risk of developing hypoglycemia because the cannabis is acting synergistically with the regular drug that is being used to treat the diabetes.”
U.S. clinicians, especially in states with legalized medical marijuana, need to be aware of the potential synergy.
“One would have to consider the patient as a whole,” he stressed. “For example, a woman that uses medical marijuana may actually respond differently to hyperglycemic medication.”
Conflicting reports explained by sex differences?
Evidence on whether cannabis use is linked with type 2 diabetes is limited and conflicting, the researchers wrote. They hypothesized that these conflicting findings might be explained by sex differences.
To “help inform current diabetes prevention and mitigation efforts,” they investigated sex differences in cannabis use and prevalence of type 2 diabetes in 15,602 men and women in the 2013-2014, 2015-2016, and 2017-2018 NHANES surveys.
Participants were classified as having type 2 diabetes if they had a physician’s diagnosis; a 2-hour plasma glucose of at least 200 mg/dL (in a glucose tolerance test); fasting blood glucose of at least 126 mg/dL; or A1c of at least 6.5%.
About half of respondents were women (52%) and close to half (44%) were age 18-39.
More than a third (38%) had a body mass index (BMI) of at least 30 kg/m2, indicating obesity.
Roughly 1 in 10 had a diagnosis of type 2 diabetes (13.5%) or A1c of at least 6.5% (9.8%).
Close to a fifth smoked cigarettes (16%). Similarly, 14.5% used cannabis at least four times a week, 3.3% used it less often, and the rest did not use it. Half of participants were not physically active (49%).
Just over half had at least a college education (55%).
Heavy cannabis users were more likely to be younger than age 40 (57% of men, 57% of women), college graduates (54% of men, 63% of women), cigarette smokers (79% of men, 83% of women), and physically inactive (39% of men, 49% of women).
Among women, heavy cannabis users were 49% less likely to have type 2 diabetes than nonusers, after adjusting for age, sex, race/ethnicity, educational level, physical activity, tobacco use, alcohol use, marital status, difficulty walking, employment status, income, and BMI (adjusted odds ratio, 0.51; 95% confidence interval, 0.31-0.84).
There were no significant differences between light cannabis users versus nonusers and diabetes prevalence in women, or between light or heavy cannabis users versus nonusers and diabetes prevalence in men.