A new study finds that African-Americans and Latinos are significantly more likely to experience serious depression than whites.
The study also found that African-Americans and Latinos were more likely to have higher levels of chronic stress and more unhealthy behaviors.
To examine the relationship between unhealthy behaviors, chronic stress, and risk of depression by race and ethnicity, researchers used data collected on 12,272 participants, aged 40 to 70 years, from 2005 to 2012.
The data was part of the National Health and Nutrition Examination Survey (NHANES), a nationally representative health interview and examination survey of U.S. adults. This age range population was selected for this study to capture the effects of chronic stress over the lifetime of the participants, researchers explain.
“Understanding the social and behavioral complexities associated with depression and unhealthy behaviors by race/ethnicity can help us understand how to best improve overall health,” said senior author Dr. Eliseo J. Pérez-Stable, director of the National Institute on Minority Health and Health Disparities (NIMHD). NIMHD is part of the National Institutes of Health.
The relationship between race and depression is complex, and different measures have found varying risk.
The National Institute of Mental Health has found that African-Americans have a lower lifetime risk of depression than whites. But according to a 2010 study by the Centers for Disease Control and Prevention, African-Americans have the highest rate of current depression (nearly 13 percent), followed by Hispanics (11 percent), and whites (8 percent).
The unhealthy behaviors the scientists examined included current cigarette smoking, excessive or binge drinking, insufficient exercise and a fair or poor diet.
The researchers measured chronic stress using 10 objective biological measures, including blood pressure, body mass index, and total cholesterol. The researchers then assessed risk for depression using results from the Patient Health Questionnaire (PHQ-9).
Chronic stress during adulthood may be an important factor in depression, researchers noted.
This effect may be worse among racial and ethnic minorities due to the stress experienced from social and economic inequalities, but the relationships between race/ethnicity, stress, behavior, and depression are not well understood, they add.
According to the researchers, a theoretical framework called the Environmental Affordances model has been proposed to explain how chronic stress and risk behaviors interact to affect health. This model proposes, for example, that engaging in unhealthy behaviors actually reduces the effects of chronic stress on depression in African Americans.
The research team say they designed this study to gain a better understanding of the relationship between chronic stress and the chance for depression by race and ethnicity.
The study asked whether unhealthy behaviors — current smoking, excessive or binge drinking, insufficient exercise, and a fair or poor diet — reduce the chance for depression due to chronic stress in African=Americans, but increase the chance for depression due to chronic stress in Latinos.
On average, Latinos and African Americans had more chronic stress, more unhealthy behaviors, and more chance for depression.
However, the study found that engaging in more unhealthy behaviors was strongly associated with greater chance for depression only in African-Americans and whites.
Contrary to previous research, this study found that in all three racial/ethnic groups, chronic stress levels were inversely related to excessive or binge drinking — for example, more stress, less excess drinking, researchers reported.
This study also found no evidence — as some previous research has suggested — that African-Americans engage in unhealthy behaviors as a way to cope with chronic stress and reduce depression or that unhealthy behaviors interact with chronic stress in Latinos to increase depression.
According to the researchers, the Environmental Affordances model was not supported for any of the racial/ethnic groups analyzed.
The scientists point to differences in their research design and their use of physiological measures of chronic stress instead of self-reported measures as possibly contributing to their different findings.
They add that their results highlight the complex relationships between chronic stress, unhealthy behaviors, and mental health among different racial and ethnic groups.
The study was published in Preventive Medicine.