Among the myriad benefits cannabis can offer, it looks like the plant medicine may be linked to lower blood pressure levels.
According to new data published in the journal Nature: Scientific Reports that assessed the relationship between cannabis consumption and blood pressure in a cohort of more than 91,000 subjects, both current and lifetime cannabis use are associated with lower blood pressure levels. These results were observed among all consumers but in a “higher manner in women,” according to the study.
French researcher Alexandre Vallée conducted the study, “Association between cannabis use and blood pressure levels according to comorbidities and socioeconomic status,” noting the conflicting evidence surrounding cardiovascular risks of cannabis use. Vallée also cites the limited population focus of past studies, along with the fact that few studies surrounding cardiovascular health and cannabis look specifically at differences between sexes.
A Closer Look at Cannabis and Blood Pressure
The study used data from the UK Biobank, a prospective cohort for the investigation, prevention, diagnosis and treatment of chronic diseases, like cardiovascular diseases in adults.
For this study, 156,959 volunteers of the UK Biobank who responded to the question of cannabis use and with blood pressure measurement were recruited. Of this group, the study excluded 65,798 for missing data; uncategorized variables; and excluding participants with antihypertensive drugs, antidepressant drugs and previous cardiovascular events.
Systolic and diastolic blood pressure were measured twice at the assessment center, either by the use of an automated blood pressure device or manually using a sphygmomanometer, inflatable cuff and stethoscope if other measures failed.
(Systolic blood pressure measures the pressure in your arteries when your heart beats, while diastolic blood pressure measures the pressure in your arteries when your heart rests between beats.)
Cannabis use was documented through a self-reported questionnaire, where participants were asked about their cumulative lifetime cannabis use. Those who said they had never used cannabis were classified as controls while those who said they had used cannabis, even if it was “a long time ago,” were classified as cannabis users.
Using other questions involving frequency of use and last cannabis use, cannabis users were additionally separated into additional groups to denote their level of cannabis use, i.e. every day, once a week or more but not every day, once a month or more but not every week and less than once a month. Users were also further categorized into groups like current and former cannabis users.
“In adjusted covariates models, lifetime heavy cannabis use was associated with decrease in both SBP [systolic blood pressure], DBP [diastolic blood pressure] and PP [pulse pressure] in both genders, but with a higher effect among women … Current cannabis use was associated with lower SBP levels in men and in women. Same results were observed for DBP and PP,” the study reads.
No Cut-and-Dry Answers
The investigator notes that other studies have suggested a strong association between cannabis use and systolic blood pressure than cannabis use and diastolic blood pressure, citing that overall, the relationship between cannabis and blood pressure as a whole is still unclear.
Among other variables, the study also notes that cannabinoid content could play a role. Recent studies have shown that CBD could reduce blood pressure and presents vasorelaxation actions in arteries. THC similarly has been associated with vasorelaxation, though studies conducted on this topic have also been inconsistent, suggesting that THC presents different effects on vessels depending on central or peripheral properties of arteries.
“Nevertheless, the abrupt cessation of cannabis use was associated with increase in [blood pressure],” the discussion states.
Among other variables, alcohol consumption also showed a possible confounding action regarding cannabis use and systolic blood pressure, though pharmacokinetic interactions have yet to be explored in depth.
The study focused on middle-aged U.K. participants, so the results could not be generalized to other age and ethnic populations. The study also didn’t establish data on frequency of cannabis use around the 30 days prior to the interview, leaving it challenging to distinguish whether the relationship between cannabis and blood pressure was short-term or chronic in nature. The study also didn’t estimate THC or CBD, and not data were presented for consumption methods.
While there are still a fair amount of questions to be explored on this topic, one major strength of the study was the large sample size of the UK Biobank cohort.
“Nevertheless, the small association in BP differences between heavy cannabis users and never users or between current cannabis users and never users remain too small to adopt cannabis-blood pressure policy in clinical practice,” the study concludes. “Longitudinal studies are needed in general populations and then, in hypertensive patients to highlight the potential lowered BP effect of cannabis in a medical use.”