Ambient PM_2.5 components and prevalence of chronic kidney disease: a nationwide cross-sectional survey in China

Chronic kidney disease (CKD) is a global public health concern, and accumulating evidence has indicated that air pollution increases the odds of CKD. However, a limited number of studies have examined the long-term effects of ambient fine particulate matter (PM_2.5) components on the risk of CKD among general population; thus, major knowledge gaps remain.

Using data from a nationwide representative cross-sectional survey in China and a validated PM_2.5 composition dataset, we established generalized linear models to quantify the association between five major components of PM_2.5 and CKD prevalence.

There were significant associations between long-term exposure to three PM_2.5 components [including black carbon (BC), sulfate (SO₄²⁻), organic matter (OM)] and increased odds of CKD prevalence. Along with an interquartile range (IQR) increment in BC (3.3 μg/m³), SO₄²⁻ (9.7 μg/m³), and OM (16.2 μg/m³) at a 4-year moving average, the odds ratios (ORs) for CKD prevalence were 1.28 (95% CI 1.07, 1.54), 1.23 (95% CI 1.03, 1.45), and 1.23 (95% CI 1.02, 1.47), respectively. We did not detect any significant association of the other two PM_2.5 components [nitrate (NO₃⁻) or ammonium (NH₄⁺)] with CKD prevalence. Stratified analyses revealed no differences (P ≥ 0.05) in the effect estimates of subgroups based on administrative region, sex, age, and other demographic characteristics. For instance, along with an IQR increment in BC at a 4-year moving average, the ORs of CKD prevalence among males and females were 1.30 (95% CI 0.98, 1.73) and 1.29 (95% CI 1.01, 1.65), respectively. The odds of CKD were generally higher with increasing PM_2.5 composition concentration.

Our study demonstrated that long-term exposure to specific PM_2.5 components including BC, SO₄²⁻, and OM increased CKD risk in the general population. This study could provide new insights into source-directed PM_2.5 control and CKD prevention.