Your smoking habit may be taking a toll on more than just your heart and lungs, new research suggests. According to a study carried out by researchers at Stanford University Medical Center, smokers may be more likely to stay unemployed longer, and earn less, than non-smokers.

Researchers have discovered links between smoking and unemployment in past studies. In 2012, for example, the Office for National Statistics in the UK found that unemployed people were twice as likely to smoke than those who were employed. However, it was never clear whether the link was causative or correlative — if smoking fueled unemployment or unemployed people were simply more likely to pick up a cigarette due to stress.

“You don’t know if smokers have a harder time finding work or if smokers are more likely to lose their jobs — or that when nonsmokers lose their jobs, they become stressed and start to smoke,” said Judith Prochaska, associate professor of medicine at Stanford and lead author of the study, in a press release.

Because of this uncertainty, Prochaska and her team wanted to set up a study that could prove that smoking actually prevents people from finding jobs. They surveyed 131 unemployed smokers and 120 unemployed nonsmokers at the start of the study, at six months, and once again at 12 months. They used a breath test for carbon monoxide levels to see whether the participants smoked daily or whether they didn’t smoke at all. At the end of the year, only 27 percent of the smokers had found jobs compared to 56 percent of non-smokers. In addition, smokers earned $5 less per hour on average than nonsmokers.

“The health harms of smoking have been established for decades,” Prochaska said, “and our study here provides insight into the financial harms of smoking both in terms of lower re-employment success and lower wages.”

Why are smokers more likely to be barred from jobs than nonsmokers? While Prochaska’s study didn’t fully investigate the reasons behind it, other researchers have explored this before. An Ohio State University study from 2013 found that smokers cost employers an extra $5,816 in health care costs and lost productivity from smoking breaks compared to nonsmokers. Smokers also will likely be faced with a slew of health problems, from fatigue and coughing to long-term diseases like lung cancer, heart disease, or chronic bronchitis. Even when smokers try to quit, withdrawal symptoms can lead to sick leave. With this financial burden in mind, employers who smell stale cigarette smoke on an interviewee’s coat might skip them over for a healthier fit.

That said, there were still a few disadvantages to the study. For one, most of the smokers surveyed were younger, poorer, and less educated than the nonsmokers in the study — so it’s possible those factors played a role in preventing them from finding jobs. Because of these differences, the researchers did try to design “this study’s analyses so that the smokers and nonsmokers were as similar as possible in terms of the information we had on their employment records and prospects for employment at baseline,” said Michael Baiocchi, assistant professor of medicine at Stanford and an author of the study, in the press release. However, this may be one of the reasons why further research is needed to solidify the link.

For their next steps, the researchers are already working on another study in which smoking job seekers receive an intervention to help them quit. If those who quit smoking have an easier time getting hired than those who don’t quit, the researchers may have the evidence needed to conclude that smoking does indeed impair the job search.

Source: Prochaska J, et al. JAMA Internal Medicine. 2016.