NEW YORK—African Americans who live below the poverty line feel the impact beyond basic needs such as food and shelter. Low income is more strongly associated with chronic kidney disease among African Americans than it is among whites, according to a study published in the November issue of the National Kidney Foundation's (NKF's) American Journal of Kidney Diseases (AJKD).
African Americans already have a three to four-fold increased risk of developing kidney failure over whites, but the new study indicates that being poor may be a unique indicator of kidney disease risk for African Americans.
Poverty and African Americans
"Our overarching hypothesis is that there’s something different about being poor for African Americans," said Deidra Crews, MD, assistant professor of Medicine at Johns Hopkins University School of Medicine's Division of Nephrology. "While poor whites are impacted by kidney disease as well, we assume that the cause is obesity and diabetes. Once we adjust for those conditions, the association disappears. That leads to the argument that there’s something different, un-adjustable, in terms of what it means to be poor and African American.”
The study included 22,800 black and white adults living in cities across the United States. Participants underwent extensive laboratory testing, including markers of kidney disease and answered questions about their income and health.
Results showed that African Americans who had incomes of less than $20,000 had more than three times the risk of excessive protein in the urine—an indicator of chronic kidney disease-- than African Americans earning more than $75,000. These findings were adjusted for age, sex, diabetes, high blood pressure and lifestyle factors such as obesity and smoking.
Those with incomes between $20,000 and $35,000 had more than double the risk of kidney damage when compared to higher income African Americans. This trend was not seen among whites.
“It’s possible that cultural differences, especially in dietary habits, may be at play as well as lack of access to healthier food options,” Crews said. “Environment could be another major factor as well as the psychological stress of poverty, which may be different for African Americans.”
Importance of Screening
“This study’s findings highlight how important it is for low income African Americans to be screened for chronic kidney disease and its risk factors. Clinicians should consider asking their patients about their socioeconomic status to help determine their likelihood of developing kidney disease,” said Thomas Manley, director of Scientific Activities for the NKF. "This information could also help clinicians advise their ‘at risk’ patients appropriately. It's important for clinicians to recognize patients with limited resources so that they can adjust their recommendations for lifestyle modifications that can reduce risk for kidney disease. Advising low income patients to join a gym or purchase expensive, healthy foods is unlikely to be effective. Clinicians need to discuss a variety of healthier options with these patients that can be accomplished within their financial means.”
Kidney Disease Facts from the National Kidney Foundation:
- 26 million Americans have kidney disease and most don't know it.
- 73 million Americans are at risk for kidney disease due to diabetes, high blood pressure or a family history of kidney disease.
- African Americans develop kidney failure at rates that are 3.5 times greater than white Americans.
- African Americans constitute over 31 percent of all patients in the U.S. receiving dialysis for kidney failure, but only represent 13.1 percent of the overall U.S. population.
- Diabetes is the leading cause of kidney failure in African Americans. African Americans are two times as likely to be diagnosed with diabetes as non-Hispanic white Americans.
- High blood pressure is the second leading cause of kidney failure among African Americans, and remains the leading cause of death overall in African Americans due to its link with heart attacks and strokes.