Pot vs tobacco: What science says

NEW YORK – As more states make it legal to smoke marijuana, some government officials, researchers and others worry what that might mean for one of the country’s biggest public health successes: curbing cigarette smoking.

Though there are notable differences in health research findings on tobacco and marijuana, the juxtaposition strikes some as jarring after generations of Americans have gotten the message that smoking endangers their health.

“We’re trying to stop people from smoking all kinds of things. Why do you want to legalize marijuana?” a New York City councilman, Republican Peter Koo, asked at a recent city hearing about the state’s potential legalization of so-called recreational pot use.

Marijuana advocates say there’s no comparison between joints and tobacco cigarettes. A sweeping federal assessment of marijuana research found the lung-health risks of smoking weed appear “relatively small” and “far lower than those of smoking tobacco,” the top cause of preventable death in the US.

Unlike for cigarettes, there’s evidence of certain health benefits from marijuana, such as easing chronic pain. And marijuana can be used without smoking it. Most states now have legal medical pot programs; 10 states and the District of Columbia have approved recreational use. 

“They’re different products, and they need to be treated differently,” says Mason Tvert, a spokesman for the pro-legalization Marijuana Policy Project.

At the same time, studies have shown crossover between marijuana and tobacco use. And while smoking cannabis may be less dangerous than tobacco to lung health, pot doesn’t get an entirely clean slate.

Some health officials and anti-smoking activists also worry about inserting legal marijuana into the growing world of vaping, given uncertainties about the smoking alternative’s long-term effects. 

Here’s a look at the issues, science and perspectives: Smoking pot vs tobacco

While cigarette smoking is the top risk factor for lung cancer, some of scientific evidence suggests there’s no link between marijuana smoking and lung cancer. That’s according to a 2017 federal report that rounded up nearly two decades of studies on marijuana, research that’s been limited by the federal government’s classification of marijuana as a controlled substance like heroin.

While cigarette smoking is a major cause of heart disease, the report concluded it’s unclear whether marijuana use is associated with heart attacks or strokes.

But there’s strong evidence linking long-term cannabis smoking to worse coughs and more frequent bouts of chronic bronchitis, according to the report from the National Academies of Sciences, Engineering and Medicine.

The report also looked at other effects, finding a mix of possible risks, upsides and unknowns. For example, the report said marijuana can ease chemotherapy-related nausea and adults’ chronic pain but also found evidence the drug is linked to developing schizophrenia and getting in traffic crashes.

In recent weeks, studies have echoed concerns about high-potency pot and psychosis and documented a rise in marijuana-related emergency room visits after legalization in Colorado.

Tobacco and marijuana use can also go together. Blunts – marijuana in a cigar wrapper that includes tobacco leaves – have gained popularity. And studies have found more cigarette smokers have used pot, and the other way around, compared to nonsmokers.

“One substance reinforces the use of the other, and vice versa, which can escalate a path to addiction,” says Dr. Sterling McPherson, a University of Washington medical professor studying marijuana and tobacco use among teens.

The National Academies report found pot use likely increases the risk of dependence on other substances, including tobacco.

To some public health officials, it makes sense to legalize marijuana and put some guardrails around it.

“For tobacco, we know that it’s inherently dangerous and that there is no safe amount of tobacco to use,” says New York City Health Department drug policy analyst Rebecca Giglio. Whereas with marijuana, “we see this as an opportunity to address the harms of criminalization while also regulating cannabis.”