Researchers in China recently looked at the relationship between kidney stone rates among male cannabis users versus those who do not consume cannabis and found that, indeed, that male cannabis users “were inversely associated with kidney stones.” The study was published in the journal Frontiers in Pharmacology.
Kidney stones have been documented in humans for thousands of years. Also called renal calculi, nephrolithiasis or urolithiasis, they describe hard deposits made of minerals and salt that form in the kidneys and may pass through a person’s urinary tract. Passing a kidney stone can be incredibly painful, though stones typically cause no permanent damage so long as they are recognized in a timely fashion.
For some, passing a kidney stone may entail pain medication and drinking plenty of water, though stones can also become lodged in the urinary tract, which may require surgery to remove.
Kidney stones are more likely to develop in males than females, though a number of other risk factors are associated with developing kidney stones, such as genetics, dehydration, exercise habits, diet and digestive diseases, among others.
Kidney Stones and Cannabis Use: A Potential Link?
To investigate the potential relationship between cannabis use and kidney stones, a team of Chinese researchers assessed a representative sample of more than 14,000 U.S. subjects between the ages of 20 and 59. Data were obtained from the National Health and Nutrition Examination Survey from 2009 to 2018, with kidney stone and cannabis use data collected from self-report questionnaires.
Researchers used multivariate logistic regression and multiple sensitivity analyses to examine the link between cannabis use and kidney stones. They also note that, to their knowledge, this was the first cross-sectional study to explore the association between cannabis use and kidney stone risk from this population-based dataset.
“Our findings suggested that marijuana use was inversely associated with kidney stones in males,” authors state. “Furthermore, we found a regular marijuana use (<6 times/week) indicated a negative relationship with kidney stones in the male population. However, no such differences were found in the overall and female populations.”
Since cannabis consumption is not as accessible in most countries, authors note that there is limited data already available investigating the relationship between cannabis use and diseases. Though, researchers explain a potential reason for this link.
Cannabis Use May Prevent Kidney Stone Formation in Males
Researchers lay out a theory as to why cannabis use may be associated with lower rates of kidney stones. According to the study, previous studies have demonstrated that “cannabinoid application increased urine output without affecting the excretion.”
That means that the diuretic effects of cannabinoids, or those effects that help to reduce buildup, may shorten the time of crystal remaining in the kidney, which therefore decreases the risk of kidney stone formation, researchers note.
“Furthermore, cannabidiol, a main component of cannabis, exerts benefits in anti-inflammatory and antioxidant effects,” researchers continue. They also note that crystal deposition in the kidney is related to the regeneration of reactive oxygen species and inflammasome activation, “Hence, it is speculated that cannabidiol has natural advantages in attenuating inflammatory responses and reducing oxidative stress,” they add.
What About Female Cannabis Users?
As the study found “no association between marijuana use and kidney stone in females,” researchers hypothesized that hormone level “could not regulate this association.” They also note that a previous study demonstrated that lower urinary saturation of stone-forming crystals “might be the reason for less kidney stone formation in females,” suggesting that estrogen may be associated with a lower risk of kidney stones. Postmenopausal females also had a higher risk of kidney stones.
“It is speculated that estrogen might overwhelm the impact of marijuana use on kidney stones. Therefore, marijuana use might have an insufficient association with the risk of kidney stones in the female population,” researchers state.
While the findings merit future research to investigate the dose and type associations of cannabis with kidney stones, researchers conclude that, “Taken together, our findings suggested that regular marijuana male users were related to a lower risk of kidney stones. Marijuana use for one to six times/week was inversely associated with the risk of kidney stones in males.”