Residence in the so-called stroke belt of the southeastern United States is an independent risk factor for incident chronic kidney disease (CKD), according to a recent study.
Individuals who live in that region, which includes Alabama, Arkansas, Georgia, Louisiana, Mississippi, North Carolina, South Carolina, and Tennessee, have a significant 14% higher risk for incident CKD compared with individuals who do not, in a fully adjusted model, Katharine L. Cheung, MD, PhD, of the Larner College of Medicine at The University of Vermont in Burlington, and colleagues reported in the American Journal of Kidney Diseases. Residence in the stroke belt also is a risk factor for decline in estimated glomerular filtration rate (eGFR).
In addition, the investigators found that albuminuria is a stronger risk factor for CKD in the stroke belt compared with other regions.
“It is noteworthy that the increased risk of CKD among residents of the US stroke belt was independent of established CKD risk factors that disproportionately impact the southeastern US, including smoking, diabetes, low socioeconomic status and cardiovascular disease,” Dr Cheung’s team wrote. “These findings suggest that other factors may contribute to the development of incident CKD in those residing in the US stroke belt.”
Compared with the rest of the United States, people living in the southeast may experience differences in environmental exposures such as heat, air pollution, or water quality, all of which have been linked to kidney disease, the investigators explained.
The findings emerged from an observational longitudinal cohort study that included 7799 White and 4198 Black individuals aged 45 years or older who participated in the prospective REGARDS (REasons for Geographic and Racial Differences in Stroke) study, which enrolled participants from 2003 to 2007.
During a mean follow-up of 9.4 years, incident CKD developed in 1067 participants (9%), with minimal differences by sex and race groups, the investigators reported. The probability of incident CKD, however, differed by age strata, ranging from 4% for individuals aged 45 to 54 years to 18% for those aged 75 years or older.
Investigators defined incident CKD as a new eGFR value less than 60 mL/min/1.73m2 and a 40% or greater decline in eGFR or kidney replacement therapy in participants with an eGFR value of 60 mL/min/1.73m2 or higher at baseline.
Among other findings, the study revealed that traditional CKD risk factors account for the higher risk for incident CKD and eGFR decline among Black vs White adults, “supporting the focus on addressing modifiable risk factors such as diabetes, hypertension and obesity in reducing disparities in CKD.”
In a demographics-adjusted model, Black vs White race was independently associated with a 39% increased risk for CKD. Black race, however, was no longer associated with incident CKD in a fully-adjusted model that took into account systolic blood pressure, body mass index, diabetes, albuminuria, hyperlipidemia, cardiovascular disease, and use of ACE inhibitors, angiotensin receptor blockers, and nonsteroidal anti-inflammatory drugs, among other variables.
Cheung KL, Crews DC, Cushman M, et al. Risk factors for incident CKD in Black and White Americans: The REGARDS Study. Am J Kidney Dis. Published online January 5, 2023. doi:10.1053/j.ajkd.2022.11.015