Electronic Theses and Dissertations

Date

2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy

Department

Epidemiology

Committee Chair

Dr. Abu Mohammad Naser Titu

Committee Member

Csaba P. Kovesdy

Committee Member

Fawaz Mzayek

Committee Member

Matthew Paul Smeltzer

Committee Member

Xichen Mou

Abstract

This dissertation examines how ambient temperature influences renal health across three complementary chapters by exploring: sex-stratified temperature-urine biomarkers relationships, a global comprehensive synthesis of evidence on renal colic, and mediation effect of BP in the biological pathway between ambient temperature and proteinuria. We used repeated measurements of urinary electrolytes, 24-h urine total protein (UTP), and volume as outcomes from a stepped-wedge RCT conducted in southwest coastal Bangladesh and collected daily ambient temperature data from Bangladesh Meteorological Board (BMD). We employed piece-wise linear mixed effect models using random intercepts to demonstrate ambient temperature and urine biomarker’s relationships. We summarized global evidence on ambient temperature-renal colic relationship through systematic literature reviews and synthesizing evidence using random-effect meta-analysis. We explore the mediating effects of blood pressure (BP) in the relationship between ambient temperature and UTP. We pooled three longitudinal studies in Bangladesh, comprising a total of 9988 person-visit data that includes 24-h UTP, BP, and other sociodemographic and individual -level information. We obtained ambient temperature data from NASA POWER and used lag temperatures for past 7 days as exposure. We employed Baron & Kenny’s product method and causal mediation analyses to estimate direct and BP-mediated indirect effects of ambient temperature on UTP. We found no sex difference in ambient temperature -urine biomarkers’ relationships, suggesting women equally vulnerable to temperature -induced kidney impairment as men. Our meta-analysis for heat effect showed that each 1ºC higher daily ambient temperature increased the risk of renal colic by 2.4% (95% CI: 1.020, 1.028) with a relatively stronger association for urolithiasis (1.024; 95% CI: 1.016, 1.029) compared to non-urolithiasis (1.015; 95% CI: 1.011, 1.016) causes of renal colic. We found a positive direct effect of ambient temperature on UTP across several lag days in Baron and Kenny’s product method. For a 10 °C increase in average daily ambient temperature the direct effect geometric mean ratio (GMR) on UTP was 1.05 (95% CI: 1.00, 1.10), corresponding to an 5% increase (95% CI: 0%, 10%) of UTP at lag 1 and for other lag days (2-7) it ranges from 6% to 9%. We found consistent results in causal mediation analyses.

Comments

Data is provided by the student.”

Library Comment

Dissertation or thesis originally submitted to ProQuest.

Notes

Open Access

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