This Could Be the Worst News for Marijuana Stocks Since Jeff Sessions' Appointment

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Marijuana-stock holders were understandably rattled when President Trump selected Jeff Sessions as attorney general several months ago. Sessions is a longtime opponent to legalization of marijuana. So far, there haven't been any substantive efforts to target the marijuana industry in states that have legalized medical or recreational marijuana. However, concerns that Sessions could make such a move remain.

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Now, though, there's news that could rattle investors even more. A recent medical study found troubling health issues associated with marijuana use. This could be the worst news for some marijuana stocks since Sessions' appointment as attorney general.

Worse than tobacco?

In a recent study published in the European Journal of Preventive Cardiology, lead author Barbara A. Yankey of the School of Public Health at Georgia State University and a team found that marijuana use could present a greater risk to cardiovascular health than smoking tobacco cigarettes. That's worrisome, considering the significant risk factor that smoking cigarettes is for high blood pressure and poor cardiovascular health. 

And this study didn't just find that marijuana could be a little worse than cigarettes. The Georgia State University researchers reported that marijuana users were greater than three times as likely to die from hypertension as non-users. The longer individuals used marijuana, the higher their risk of death from hypertension. However, no link was found between marijuana use and death from heart disease or cerebrovascular disease.

The Georgia State team analyzed data from a National Health and Nutrition Examination Survey (NHANES) conducted back in 2005 and 2006. This survey included 1,213 participants ages 20 and over. Roughly 57% of the participants had used marijuana either currently or in the past. The average duration of marijuana use was 11.5 years.

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The researchers merged the NHANES data with 2011 mortality data from the National Center for Health Statistics. They then estimated the links between marijuana use and duration of use, with death from hypertension, heart disease, and cerebrovascular disease. The team controlled for cigarette use and demographic variables, including sex, age, and ethnicity, in the statistical analysis.

Yankey stated:

Our results suggest a possible risk of hypertension mortality from marijuana use. This is not surprising, since marijuana is known to have a number of effects on the cardiovascular system. 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.

Is this a big deal?

If marijuana truly can lead to higher death rates from hypertension than cigarettes, this recent study could be a big deal. Why? Marijuana legalization proponents highlight the safety of using marijuana. The American public currently views marijuana as safer than smoking cigarettes or drinking alcohol. Support for marijuana legalization would likely drop if the drug presents more health risks than many now believe it does.

Several states could be on the verge of legalizing recreational use of marijuana. New Jersey's upcoming election in November could put the state on the path to become the second-largest state after California for legal recreational use of the drug, with the Democratic candidate for governor supporting legalization. However, expect legalization opponents to extensively use the recent Georgia State study identifying serious health concerns about marijuana.

The latest information also plays into the hands of Sessions and others in the Trump administration who would like to clamp down on marijuana businesses in states that have already legalized marijuana. Their argument could be that steps to enforce federal anti-marijuana laws are needed to protect public health.

Potential losers

The marijuana stocks that would probably be the most affected if concerns grow over the health impact of marijuana are those of tiny U.S.-based marijuana growers. It's also possible that there could be spillover impact for Medical Marijuana Inc. (NASDAQOTH: MJNA). Although the company's products use hemp and don't violate federal laws, any downturn in the public perception of marijuana safety could hurt the stock.

It doesn't seem likely that Canadian marijuana providers would be affected too much. The horse appears to have left the barn for legalization of recreational use of marijuana in Canada. And Canopy Growth (NASDAQOTH: TWMJF) is among the companies benefiting from the legalization of medical marijuana in Germany earlier this year. 

Note, however, that we're only talking about potential losers if health concerns about marijuana increase. This tentative language is appropriate. The Georgia State study is only one study right now. There hasn't been additional research to confirm the link between marijuana use and increased risk of death from hypertension.

Also, as is the case with many studies, this recent report only identified a potential statistical correlation between marijuana use and cardiovascular risk. What the researchers didn't point to was a solid causal connection between the two.

In addition, there were some drawbacks to the Georgia State study. One biggie: Lead author Yankey pointed out that there was no way to know if survey participants kept using marijuana continuously since they first tried it. Yankey also acknowledged that the number of cigarette smokers in the study was small. 

If the latest research is confirmed, though, expect an even tougher battle for further legalization of marijuana in the United States. An airtight finding that marijuana use leads to increased risk of death would be a much more serious threat to marijuana stocks than Jeff Sessions will ever be. 

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Keith Speights has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.