Abstract
<title>Abstract</title> <p> Background: Growing evidence suggests PM2.5 <sub/> is associated with adverse kidney outcomes. Identifying harmful PM2.5 components can help prioritize interventions to reduce PM2.5 <sub/> exposure, especially among high-risk individuals such as those suffering from chronic kidney disease (CKD). Methods: NASA SEDAC PM2.5 <sub/> component estimates were obtained for organic carbon (OC), elemental carbon (EC), ammonium (NH4), nitrate (NO3), and sulfate (SO4). They were linked at the 3-digit ZIP code level to All of Us research program participants across the contiguous United States. Participants were ≥18 years at baseline with CKD diagnoses as identified by ICD-9 and ICD-10. Weighted quantile sum (WQS) regression was used in combination with negative binomial models to examine the association between PM2.5 <sub/> mixtures and severity of CKD as indicated by inpatient hospitalization incidence. Results: Participants (2,511) were enrolled with CKD diagnoses, with the following characteristics: 47.9% female; median age, 63.5 [54.6, 70.9]; 44.1% urban residents. There were 19,656 hospitalizations among 22,448 person-years of observation time. Median PM2.5 exposure, 4.4 [3.6, 5.1] μg/m <sup>3</sup> . After adjusting for covariates, the hospitalization rate increased by 31% for a 1-quartile increase in the WQS <sub>PM2.5</sub> index (IRR: 1.31, 95% CI: 0.99, 1.73; p=0.06). The joint effect is weighted accordingly: NO3, 93%; NH4, 4%; EC, 4%; and 0% for OC and SO4. Conclusions: Mixtures of PM2.5 components were not associated with hospitalization rate among CKD participants in the All of Us research program, although, the study estimate approached statistical significance (p=0.06). The potential exposure-outcome association is almost entirely driven by nitrate (weight = 93%). </p>