Stock up on your Cheetos: Smoking one joint per day for 20 years will not damage your lungs, according to a study from researchers at Emory’s School of Medicine, set to appear in the next issue of the American Journal of Respiratory and Critical Care Medicine.
“I can’t say anything about psychological effects or overall safety,” third-year Medical School fellow Jordan Kempker, the study’s lead author, said, “but for under 20 years of exposure [to smoked marijuana] there’s no clinical effect on the lungs.”
Kempker and two co-authors, Professor Eric Honig and Associate Professor Greg Martin, both of the School of Medicine, used data from the National Health and Nutrition Survey (NHANES), a biennial Centers for Disease Control and Prevention (CDC) questionnaire including responses from about 5,000 people on everything from bowel health to pesticide use. Their study, “Effects of Marijuana Exposure on Expiratory Airflow,” examined responses from the 2007-2008 and 2009-2010 NHANES data.
Of the respondents in two sets of NHANES data, 59.1 percent had used marijuana in their lifetime and 12.2 percent had used it in the past month. To compensate for the fact that not every pot user smokes a joint daily, the researchers assigned different percentage weights to survey responders who smoked the drug at different frequencies, according to Kempker. They then measured effects on lung function in accordance with the respondents’ number of “joint-years,” or years of smoking one joint per day.
To measure lung function as part of the NHANES data measurement, respondents took a spirometry test, in which they took a deep breath and exhaled as hard as they could into a device that would measure the strength of the exhale. Doctors use two parts of this test — how much air the person can blow out in the first second, and the total amount of air exhaled — to create a ratio to measure lung health.
According to the study, frequent cigarette smokers tend to not fare well on the first part of the test, while those who smoke one joint a day for more than 20 years do poorly on the second. The reason it takes 20 years for pot smoking to damage the lungs may be because weed smokers don’t use joints nearly as often as tobacco users smoke cigarettes, Kempker said.
“It might be relative to the amount of smoking we see,” Kempker said, adding that the unit for measuring the effects of cigarette smoking is a “pack-year,” as in one pack a day for a year, unlike the “joint-year” unit (little research has been done on the effects of smoking a pack of joints each day for a year).
“People who smoke cigarettes are at significant risk of lung disease, often at one pack a day per year,” Kempker added.
As for whether the study will have any impact on the national debate over legalization of recreational marijuana use, Kempker said the findings aren’t exactly revolutionary.
“This is not controversial to a lot of what’s out there,” he said.
An Emory student and club sports athlete, who smokes marijuana occasionally but used it weekly in high school, said she felt better knowing that her lungs hadn’t been damaged, and that she would still be able to play her endurance-heavy sport for many years to come. (She wished to remain anonymous, as possession and personal use of the drug remains illegal in Georgia.)
“Knowing that it definitely doesn’t affect my lungs is a calming factor,” she said.
— By Lydia O’Neal, Asst. News Editor
Study Shows ‘High’ Prospects For Marijuana Smokers
Photo courtesy of Flickr Creative Commons
