New research finds that self-employed women have fewer risk factors for cardiovascular disease (CVD) compared to non-self-employed women, suggesting that the work environment may play a role in the development of risk factors that can lead to heart attacks.
While the findings also showed some positive associations between health outcomes and self-employment among white men, the researchers found women had the most favorable CVD risk profile associated with being self-employed, possibly because they are more likely than men to experience stress and time demands related to balancing responsibilities across work and home.
Self-employed men of color, by contrast, did not experience the same health benefits.
The study is one of the few to use measures obtained from lab tests and body measures, rather than relying on self-reported measures, to explore the relationship between self-employment and heart disease risk factors, said lead author Dr. Kimberly Narain , assistant professor-in-residence of medicine in the division of general internal medicine and health services research at the David Geffen School of Medicine at UCLA . It is also the only study to consider differences across sex and racial/ethnic minority status.
"There is a relationship between self-employment and heart disease risk factors and this relationship seems to be stronger in women relative to men," said Narain, who is also director of health services and health optimization research at the Iris-Cantor-UCLA Women's Health Center. "It is imperative to increase our understanding of how the work environment gets under our skin so we can come up with ways to ensure that everyone has access to a healthy work environment."
The study will be published in the peer-reviewed journal BMC Public Health.
Prior studies have shown links between the structure of employment and cardiovascular disease risk. Some have found better health outcomes among people in executive positions compared with those in clerical or administrative positions, which are frequently held by women and people of color. Others have found ties between job control and health benefits. For instance, high strain jobs with higher psychological demands and less autonomy have been linked with hypertension and CVD.
But many of those studies were largely dependent on self-reported measures that are not entirely reliable due to factors such as recall bias.
For this study the researchers used data from 19,400 working adults in the National Health and Nutrition Examination Survey (NHANES). They analyzed the association between self-employment and CVD risk factors that included elevated cholesterol, hypertension, glucose intolerance, obesity, poor diet, physical inactivity, smoking, binge drinking, sub-optimal sleep duration and poor mental health. They explored these questions across sex, race and ethnicity, using biologic and physical measures that are more reliable than self-reported measures, in some contexts.
They found a number of negative associations—that is, lower rates of specific CVD risk factors-- between self-employment and health outcomes. These are among the key findings.
Among white women self-employment was linked to:
• 7.4 percentage point decline in obesity
• 7.0 percentage point decline in physical inactivity
• 9.4 percentage point decline in poor sleep duration
Among women of color it was linked to:
• 6.7 percentage point decline in poor diet
• 7.3 percentage point decline in physical inactivity
• 8.1 percentage point decline in poor sleep duration
And among white men, self-employment was associated with:
• 6.5 percentage point decline in poor diet
• 5.7 percentage point decline in hypertension
The researchers did not find the same benefits among self-employed minority men, possibly because they are generally in businesses with high entry barriers and failure rates, and they may also struggle with lower financial capital and less access to mentorship that could better prepare them to maintain a successful business, the researchers write.
Due to the study's cross-sectional nature, the researchers can't make causal claims from their findings. Other study limitations include the possibility that unmeasured characteristics, such as personality traits and coping mechanisms, may affect individuals' choice to be self-employed and their development of CVD risk factors. The researchers also could not distinguish between individuals who chose self-employment and those who were forced into it due to job loss or other circumstances.
Study co-authors are Daniela Markovic and Dr. Jose Escarce of UCLA.
The research was funded by the Leichtman-Levine-TEM Mentorship in Women's Health Research at the Iris-Cantor-UCLA Women's Health Center, and the Tides Foundation (TFR15-00194).
