Long-Term Frequent Cannabis Use and Related Serum Cannabinoid Levels Are Not Associated with Kidney Dysfunction

Human studies about the impact of cannabis use on both healthy kidneys as well as kidney function in patients with kidney disease are lacking. To shed more light on this understudied topic, we reevaluated a previous clinical study. The sample of this study was exclusively suited for investigating effects of recreational long-term cannabis use on humans under real-life conditions. This special sample had sought and was undergoing inpatient detox-treatment. It was characterized by a lone and considerable cannabis-dependence without any other relevant active comorbidity (except of a concurrent nicotine-dependence). In the present analysis, we are focused on this sample's routine laboratory tests at admission, including the glomerular filtration rate (GFR), which is the key routine parameter for kidney function assessment. Next, we investigated the association between participants' GFR and their cannabis-related data, including serum cannabinoid levels (Δ-9-tetrahydrocannabinol and main metabolites 11-Hydroxy-Δ-9-tetrahydrocannabinol and 11-Nor-9-carboxy-Δ-9-tetrahydrocannabinol). In the whole sample (=42; 9 females; mean 28.7 years old), we found five persons (12%; 95% confidence interval [2.1-21.7%]) with a mild kidney dysfunction (GFR; 86-75 mL/min). These persons (two females), however, had reported a stronger nicotine misuse. Furthermore, we found no significant association between the study-populations' GFR and reported cannabis burden (median daily use 2.5 g for 36 months, moderate general symptom-load). Most remarkably, the GFR was also not significantly correlated with the serum cannabinoid-levels. Chronic recreational cannabis-use (including its related discomfort) did not affect the kidney function of our almost selectively "cannabis-burdened" population in a relevant manner.