Air pollutants, heat exposure, and kidney health: A longitudinal study in women in Central America

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Project Summary/Abstract The overarching goals of this proposal are to contribute to the understanding of the causes, mechanisms, and potential strategies for prevention of the epidemic of chronic kidney disease of unknown origin (CKDu). Our central hypothesis is that exposure to high concentrations of airborne contaminants will be associated with kidney injury, cellular stress, and systemic inflammation in females at-risk for CKDu in Guatemala and Nicaragua. Nearly all research to date has focused on males, neglecting preliminary data showing that females working in agriculture and living in agricultural communities in Central American countries are also affected by CKDu. Additionally, studies to date have largely overlooked consideration of air pollutants as contributors to CKDu etiology. Given community pathways the potentially high exposures among Central American women from i n-home cooking sources, ambient air pollution, and agricultural sources, this is an ideal population to explore these potential linking exposure with kidney injury. In this proposal, we will characterize occupational and non- occupational airborne exposures to particulate matter (PM), silica, and metals over repeat 8-hour monitoring periods in 200 female sugarcane workers across three years (Aim 1). We will conduct 8-hour monitoring for each participant at three time points, twice during the harvest, when exposure is highest, and once during the off- season. We will evaluate the relationships between individual exposures (PM, silica, and metals) and risk factors (heat stress and dehydration), mechanisms of injury (kidney injury molecule-1, neutrophil gelatinase-associated lipocalin, and uromodulin), heat-associated and cellular stress (heat shock protein 70), and inflammation (C- reactive protein, white blood cells, and cytokines), and kidney biomarkers of effect (serum creatinine and cystatin C) both acutely (Aim 2) and longitudinally (Aim 3). In addition, we will utilize novel statistical techniques, Bayesian kernel machine regression (BKMR), weighted quantile sum (WQS) regression and/or quantile g-computation, to estimate the effects of airborne pollutant mixtures on kidney injury and inflammation (Sub Aim 2.1). The overall goal of the study is to increase understanding of risk factors for CKDu in females to facilitate future research and prevention strategies. The proposed research addresses a knowledge gap in understudied, highly exposed populations: female workers in Guatemala and Nicaragua. The individual, and combined, contributions of exposures and risk factors on biomarkers of kidney dysfunction, cellular stress, and inflammation will be examined in this study. This exposure conducting stress, stress a) investigate an unexplored pathway to identify inhalation exposures that may place female agricultural workers at risk by a robust personal exposure assessment; b) evaluate the relationship between exposure(s), cellular inflammation, and kidney injury; and c) examine underlying mechanisms by which dehydration and heat contribute to increased risk of kidney injury. Results will lead to research will: intervention trials that will help prevent CKDu by targeting approaches for vulnerable populations that can be disseminated in the US and internationally.