A recent Yale study shows that marijuana use and smoking tobacco lead to similar health problems.

University researchers have found that smoking marijuana is correlated with an increased risk of conditions similar to those produced by smoking tobacco and can compound health problems resulting from smoking tobacco. Brent Moore, a professor of psychiatry at the Yale School of Medicine, led the study, which was published in the Journal of General Internal Medicine.

“What we found is that marijuana use is associated with a number of self-reported respiratory symptoms including chronic bronchitis, frequent phlegm production, shortness of breath, afrequent wheezing, chest sounds without a cold, and pneumonia,” Moore said.

While about 11 million Americans have used marijuana within the last month and 4 million are daily users, Moore said, the study focused on people who had reported using the drug at least once in the past 30 days and 100 times within their lifetime.

Some research subjects smoked tobacco in addition to marijuana, as 77 percent of marijuana users in the United States also smoke tobacco, said Richard Moser, a research psychologist at the National Cancer Institute and a co-author of the paper.

“It turns out that a lot of the marijuana smokers also smoke tobacco,” Moser said. “What we did, though, is statistically control for the number of cigarettes, and even controlling for the number of cigarettes we still found that marijuana use was associated with these respiratory problems.”

After controlling for gender, age, current asthma and tobacco cigarettes used per day, marijuana use was associated with greater odds of respiratory ailments, according to the study.

There is a greater risk of symptoms for people who smoke both tobacco and marijuana, Moore said.

The data for the study was collected from the third National Health and Nutrition Examination Survey, conducted by the National Center for Health Statistics at the Centers for Disease Control and Prevention. During a three-year period, the survey will create a statistical model for general health in the nation, said Bill Crews, a spokesman for the survey.

By relying on the Census 2000 data and its updates, the survey is designed to collect data from a range of rural, urban and suburban counties and a diverse array of participants of different ages, races, sexes, ethnicities and incomes, Crew said.

“What makes this study unique is that it is using a national sample,” Moser said.

Moore said researchers hope the study will raise awareness of the consequences of marijuana use.

“Hopefully [the study] will lead physicians to basically ask more about whether people smoke marijuana,” Moore said.