A one-year longitudinal study by researchers at the Stanford University School of Medicine strongly suggests that smokers remain unemployed longer than nonsmokers. And when smokers do find jobs, they earn substantially less than nonsmokers.
The study will be published April 11 in JAMA Internal Medicine. Judith Prochaska, PhD, MPH, associate professor of medicine, is the lead and senior author.
Previous studies have demonstrated an association between smoking and unemployment in the United States and Europe, said Prochaska. In an earlier paper, her team found that unemployed job-seekers in California were disproportionately more likely to be smokers than were people who had jobs.
Cause or effect of unemployment?
But it has not been clear if smoking is the cause or the result of unemployment. "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 Prochaska.
In a first step toward establishing that smoking may actually prevent people from getting jobs, Prochaska and her team surveyed 131 unemployed smokers and 120 unemployed nonsmokers at the beginning of the study and then at six and 12 months. "We found that smokers had a much harder time finding work than nonsmokers," said Prochaska.
At 12 months, only 27 percent of smokers had found jobs compared with 56 percent of nonsmokers. And among those who had found jobs by 12 months, smokers earned on average $5 less per hour than nonsmokers.
"The health harms of smoking have been established for decades," said Prochaska, "and our study here provides insight into the financial harms of smoking both in terms of lower re-employment success and lower wages."
Prochaska and her colleagues used survey questions and a breath test for carbon monoxide levels to classify job seekers into either daily smokers or nonsmokers. Participants were not randomized, and smokers and nonsmokers differed in a number of important ways besides whether they smoked. For example, smokers were, on average, younger, less-educated and in poorer health than nonsmokers. Such differences might influence job seekers' ability to find work, said Prochaska.
For this reason, the researchers analyzed their data to control for these and other factors, such as duration of unemployment, race and criminal record. "We designed 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 co-author Michael Baiocchi, PhD, an assistant professor of medicine who oversaw the data analyses.
After controlling for these variables, smokers still remained at a big disadvantage. After 12 months, the re-employment rate of smokers was 24 percent lower than that of nonsmokers.
Testing the hypothesis
In a follow-up study already in progress, Prochaska and her team are testing an intervention that helps job seekers quit smoking. Smokers unemployed no longer than two years are being randomized into one of two groups. Those in the treatment group receive special help to quit smoking, while those in the control group receive brief advice and referral to a help line for quitting smoking. The hypothesis is that those who successfully quit smoking will have an easier time getting hired. The researchers hope to enroll a total of 360 smokers; more than 60 have already enrolled. Residents of the San Francisco Bay Area who are interested in participating in the study can call (415) 216-5853 for more information or go to http://www.employmentsmokingstudy.com.
Other Stanford-affiliated co-authors are clinical research coordinator Anne Michalek; postdoctoral scholars Catherine Brown-Johnson, PhD, and Eric Daza, DrPh; and research assistants Nicole Anzai and Amy Chieng.
Researchers from the San Francisco Department of Veterans Affairs and the Buckelew Programs Residential Support Services, in Marin County, also contributed to the study.
The research was supported by the State of California Tobacco-Related Disease Research Program, with a Pilot Community-Academic Research Award; by the National Heart Lung and Blood Institute (grant T32HL007034); and by the Agency for Healthcare Research and Quality.
Stanford's Department of Medicine also supported the work.
Prochaska has provided expert witness testimony in litigation against tobacco companies and consults with Pfizer on smoking cessation medication.
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JAMA Internal Medicine