New research published in the European Journal of Preventive Cardiology yesterday states that the use of marijuana is linked with a three-fold risk of death due to hypertension.
According to Barbara A Yankey, the lead author and a PhD student in the School of Public Health, Georgia State University, Atlanta, various steps had been taken in the U.S towards the legalisation and decriminalisation of marijuana and as a result, there might occur a considerable rise in the rates of use of recreational marijuana. But, there is a lack in research on the effect of marijuana use on cardiovascular and cerebrovascular deaths.
As longitudinal data on the use of marijuana was not available, a retrospective follow-up study of National Health and Nutrition Examination Survey (NHANES) was designed by the researchers of the study. It included 1,213 participants aged 20 years and above.
During 2005-06, these participants were asked whether they had used marijuana ever and the ones who answered “yes” were considered as users of marijuana. They were also asked to report the age in which they first tried using marijuana. To measure the duration of use, this age was then subtracted from their current age.
Neither cigarettes, nor marijuana was used by 34% of the total participants; 21% of them used only marijuana, while 20% used both marijuana and cigarettes. Participants who used marijuana and were past-smokers consisted of 16%, and past-smokers and those who smoke only cigarettes were 5% and 4% respectively. Eleven and a half years was the average duration of marijuana use.
Combining the data on marijuana use with the National Centre for Health Statistics’ mortality data in 2011, the effect of marijuana use and the duration of use on deaths due to hypertension (which included causes like hypertensive renal disease as well as primary hypertension), cerebrovascular disease and heart disease, controlling for the use of cigarette, was estimated. Age, sex and ethnicity were the demographic variables included.
The findings of the study showed that the marijuana users possessed a greater risk of dying from hypertension. When compared with non-users, the users of marijuana were 3.42 times more likely to suffer hypertension as a cause of death, and with the addition of each year of use, the risk increased by 1.04 times.
However, no effect of use of marijuana on deaths due to cerebrovascular disease or heart disease was found.
A few limitations, such as the uncertainty in whether participants used marijuana continuously since their first trial,were pointed out by Ms. Yankey.
She also said:
Marijuana stimulates the sympathetic nervous system, leading to increases in heart rate, blood pressure and oxygen demand. Emergency rooms have reported cases of angina and heart attacks after marijuana use."
The authors also suggest that the cardiovascular risk linked with the use of marijuana might be higher indicating more complications than the cardiovascular risk which is already established for cigarette smoking. But, this needs examination in a larger research, as the number of smokers in this study was only few.
According to Ms. Yankey, harmful effects of marijuana on the functioning of the brain are more than that of cigarette smoking. Also, in order to make informed decisions, it is vital for individuals as well as the policy makers to understand the impact of marijuana on health.
"Support for liberal marijuana use is partly due to claims that it is beneficial and possibly not harmful to health”, she added. “With the impending increase in recreational marijuana use it is important to establish whether any health benefits outweigh the potential health, social and economic risks.”
If use of marijuana has any impact on cardiovascular diseases as well as deaths, then it is the responsibility of the health community and policy makers to protect the public, says Ms. Yankey.