Exposure to air pollution consisting of fine particulates less than 2.5 microns (PM2.5) in diameter independently predicts development of end-stage kidney disease (ESKD) among patients with IgA nepropathy (IgaN), new findings suggest.
“Beyond previous risk factors for IgAN, environmental pollution has recently attracted much attention because IgAN is a disease related to upper respiratory tract infection and mucosal immune disorders of the respiratory and digestive tracts,” Jingyuan Xie, MD, PhD, of Ruijin Hospital, Shanghai Jiao Tong University School of Medicine in China, and colleagues explained.
The investigators studied PM2.5 exposure across regions in China from 1998 to 2016 using satellite data on aerosols. They found that PM2.5 exposure levels increased over time and were higher among patients residing in the northern vs the southern part of the country.
Among 1979 patients with biopsy-proven IgAN at 7 Chinese centers, ESKD developed in 207. Each 10 μg/m3 increase in annual average concentration of PM2.5 exposure was significantly associated with a 14% increased risk of ESKD before study entry and a 10% increased risk after study entry, Dr Xie’s team reported in Kidney International. When patients were exposed to PM2.5 pollution above the median both before and after study entry (defined as 52.7 and 52.3 μg/m3, respectively), patients had a significant 54% increased risk for ESKD. The investigators adjusted the models for age, gender, estimated glomerular filtration rate, 24-hour urinary protein, uric acid, hemoglobin, mean arterial pressure, Oxford classification, and use of glucocorticoids and renin-angiotensin system inhibitors. The associations held when the investigators further adjusted for time period, city size, and cardiovascular risk factors.
“Overall, our results suggest that PM2.5 is an independent risk factor for [ESKD] in patients with IgAN,” Dr Xie’s team wrote.
As the study was conducted in China, results need to be validated in other geographic locations. Among the study’s limitations, it lacked granular detail on patients’ time spent in traffic or outdoors exposed to environmental air pollution and potential exposure to indoor air pollutants. The study also could not fully assess the relationship between air pollution, socioeconomic status, and access to health services.
Luo C, Ouyang Y, Shi S, et al. Particulate matter of air pollution may increase risk of kidney failure in IgA nephropathy. Kidney Int. 2022 Dec;102(6):1382-1391. doi:10.1016/j.kint.2022.08.020