Temperature, air pollution, and risk for kidney-related conditions
Date of Award
Spring 2023
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Public Health
First Advisor
Dubrow, Robert
Abstract
With the globe warming, extreme heat and deteriorating air quality are two factors that are adversely impacting human health. The kidney, as an essential organ regulating body homeostasis, is involved in the response to changes in the outer environment. However, the evidence on the associations between short-term exposure to temperature and air pollution and risk for kidney-related health conditions is insufficient. Even less is known about the sensitivity of these association estimates to how temperature is specified in the analyses. This dissertation aimed to evaluate short-term exposure to temperature (Chapter 2) and air pollution (Chapter 3), along with the interaction effects between exposure to temperature and air pollution (Chapter 4), in relation to risk for kidney-related conditions in New York State (NYS). We also assessed the role of two main temperature specifications in the estimation of associations: (1) seven temperature metrics incorporating other meteorologic variables (i.e., dry-bulb temperature, wet-bulb temperature, heat index, humidex, net effective temperature, indoor wet-bulb globe temperature [WBGT], and outdoor WBGT), and (2) five intraday temperature measures (i.e., daily mean, daily maximum, daily minimum, daytime mean, and nighttime mean). We assessed the role of these temperature specifications 1) in examining the relationship between temperature exposure and risk for kidney-related conditions; 2) in adjusting for temperature in analyses of the relationship between exposure to air pollution and risk for kidney-related conditions; and 3) in examining the interaction between temperature and air pollution exposure in relation to risk of kidney-related conditions. Finally, for our evaluation of interaction effects, to address gaps in existing methods, we proposed a unified framework to quantify the magnitude of interaction effects and their uncertainties. We obtained individual-level health data on adult unplanned hospital visits (including emergency department visits and emergency and urgent inpatient admissions) for seven kidney-related conditions (i.e., acute kidney failure [AKF], urolithiasis, glomerular diseases [GD], renal tubulo-interstitial diseases [TIN]), chronic kidney disease [CKD], dysnatremia and volume depletion) in NYS (2007-2016). We calculated temperature exposures using different temperature metrics and intraday temperature measures based on hourly dry-bulb temperature, dew point temperature, wind speed, and solar radiation from the ERA5-Land hourly dataset. We also obtained data on daily mean fine particulate matter (PM2.5) concentration, daily 1-hour maximum nitrogen dioxide (NO2) concentration, and daily 8-hour maximum ozone (O3) concentration from ensemble-based models. We designed a bi-directional symmetric case-crossover study with conditional logistic models. In all analyses, for simplicity we used daytime mean outdoor WBGT as our temperature specification because it exhibited good statistical performance across all kidney-related conditions. We observed elevated risk for AKF, urolithiasis, dysnatremia, and volume depletion associated with high daytime mean outdoor WBGT exposure within one week. We also found significant positive associations between short-term PM2.5 exposure and risk for AKF, GD, and volume depletion, and between short-term NO2 exposure and risk for AKF. When evaluating the interaction effects between temperature and air pollution, we observed additional risk for AKF due to a multiplicative interaction between high outdoor WBGT and PM2.5 and additional risk for urolithiasis due to a multiplicative interaction between high outdoor WBGT and O3. Regarding the role of temperature specification, we observed differential statistical performance and effect estimates using different intraday temperature measures when evaluating the temperature associations, the air pollution associations (with temperature adjusted in models), and the interaction effects (with temperature involved in the interaction with air pollutants), while the selection of temperature metric only played a role when estimating temperature associations. Our findings add to the evidence base on the effects of exposures influenced by climate change on human health; specifically, our research contributes foundational knowledge on the relationships between temperature, air pollution, and adverse kidney-related conditions. The sensitivity of association estimates to temperature specification indicates the importance of careful selection of temperature metrics and intraday temperature measures when estimating health burden and designing temperature/pollution alert systems. Synergistic interactions between heat and air pollution in relation to risk for kidney-related conditions emphasize the need for co-consideration of non-optimal temperature and air pollution conditions, either in research, in the design of heat/air pollution alert systems, or in allocating health care resources. The proposed framework for assessing interaction effects provides a unified perspective regarding the selection of functional forms for the environmental exposures being examined for interaction and regarding the equivalence of effect modification of one exposure by the other.
Recommended Citation
Chu, Lingzhi, "Temperature, air pollution, and risk for kidney-related conditions" (2023). Yale Graduate School of Arts and Sciences Dissertations. 894.
https://elischolar.library.yale.edu/gsas_dissertations/894
