The Effect of Habitual Cannabis Smoking on Arterial Stiffness and Vascular Endothelial Function: A Preliminary Analysis

Abstract

Cannabis ranks globally as the most commonly used recreational drug, and both recreational and medicinal use have recently been legalized in numerous states and countries. The most common means by which cannabis is consumed recreationally is via smoking. Despite its prominent global use, a thorough understanding of the chronic cardiovascular effects of habitual consumption via smoking is lacking. Previous investigations have identified an association between cannabis use and accelerated vascular aging, and rodent models demonstrate impairments in vascular endothelial function following exposure to second‐hand cannabis smoke. Given these findings, it is likely that habitual cannabis smoking by humans results in central artery stiffening and/or decrements in vascular endothelial function; outcomes which are established risk factors for cardiovascular disease. The present work compared the carotid‐femoral pulse wave velocity (cfPWV) and brachial artery reactive hyperemia flow‐mediated dilation (FMD) of habitual cannabis users (CU) and age/anthropometrically matched non‐users (NU). CU were defined by cannabis use a minimum of once per week for ≥3yr. cfPWV was measured using arterial pulse wave tonometry. The FMD protocol included a 1‐minute baseline period, a 5‐minute occlusion of the forearm, and a 3‐minute reperfusion period. FMD is reported as peak change in vessel diameter. CU (n=10, 7M, 3F) and NU (n=10, 6M, 4F) did not differ in age (CU: 21.7±0.4, NU: 21.5±1; p=0.9) nor BMI (CU: 24.2±0.6kg/m2, NU: 23.4±0.4kg/m2, p=0.6). Systolic blood pressure (CU: 111.8±6.8mmHg, NU: 113.3±2.5mmHg, p=0.7), diastolic blood pressure (CU: 68.3±1.4mmHg, NU: 70.3±2.4mmHg, p=0.5), and supine resting heart rate (CU: 65.6±1.8bpm, NU: 66.0±2.8bpm; p=0.9) were similar between groups. Peak FMD (CU: 5.9±0.9%, NU: 6.8±1.1%; p=0.6) was also similar between groups, as was 60 second shear rate area‐under‐curve (CU: 4547±510, NU:4450±572; p=0.9). Peak change in blood velocity (CU: 38.1±3.6cm/s, NU: 36.7±2.0cm/s; p=0.7) and peak change in blood flow (CU: 307±51mL/min, NU: 253±33mL/min; p=0.4) during the FMD test were similar between groups, indicating no differences in microvascular dilatory capacity. cfPWV was higher in CU than in NU (CU: 6.0±0.2m/s, NU: 5.4±0.2m/s; p=0.05). Although no differences in vascular endothelial function were observed in this analysis, an increased sample size will be necessary to confirm these findings. The present data does indicate that habitual cannabis smoking may be associated with increased arterial stiffness.Support or Funding InformationThis work was supported by the Natural Sciences and Engineering Research Council of Canada under Grant 03974.