Scientists find links between health and relative income inequality
If rising gas prices have got you down, it may be comforting to know that your friends are suffering, too.
New research from Keck School of Medicine of USC shows that, while stress and depression levels surge when a Chinese teenager thinks he earns less money than his peers, psychological health remains steady when he thinks he earns the same as or more than his peers.
“Those who thought they earned a higher income than their peers reported equally good mental health as those who thought they earned roughly the same as their peers,” said the study’s lead author, Ping Sun, assistant professor of research in the Department of Preventive Medicine at the Keck School. “The perception that you are faring just as well as others appears to help you feel better.”
Sun and colleagues from Claremont Graduate University and City of Hope examined data collected from 12,449 teen-parent pairs living in seven cities in China. The researchers looked at how self-perceived wealth relative to their peers and past affected levels of depression, stress, smoking and general health.
Compared to the perceived wealth of their peers and their own past, self-perceived poverty was associated with the worst mental and physical health, while self-perceived affluence was linked to best physical health. Surprisingly, those who reported relative affluence did not appear to experience the least amount of stress or depression, as expected; those who reported higher relative income were similar to those who reported equal income in terms of mental health.
The scientists also noted differing relationships between relative income and cigarette smoking among boys and girls. Higher income relative to others appears to be a risk factor for smoking in girls but not in boys, while higher and lower income relative to the past appear to be risk factors for smoking among boys but not girls.
“Relative affluence may not be a good indicator for behavioral health,” Sun said. “The ultimate purpose of our study is to improve health by looking at its associations with income, but, as most of us can relate, the ability to improve one’s income can be very difficult.”
Data for the analysis came from the China Seven Cities Study, a study of tobacco use and lifestyles in seven of China’s largest cities led by C. Anderson Johnson, formerly with USC but now dean of the School of Community & Global Health at Claremont Graduate University.
Because the original survey did not focus solely on relative income inequality, Sun and colleagues were limited by the measures available to study. The associations observed did not indicate causality, and they may be subject to self-reporting bias. One area for future research may consider the influence that individual personality may have on self-perceived income inequality.
The study was published in January in the peer-reviewed journal Social Science & Medicine. USC co-authors included Jennifer B. Unger, professor of preventive medicine, and Steven Sussman, professor of preventive medicine and psychology.