# NOSI to Support Enhancement of Software Tools for Multilevel Mediation Analysis for Investigating Effects of Environmental and Individual Risk Factors on Respiratory Diseases

> **NIH NIH P42** · LOUISIANA STATE UNIV A&M COL BATON ROUGE · 2021 · $226,970

## Abstract

Multilevel Mediation Analysis for Investigating Effects of Environmental and Individual
 Risk Factors on Respiratory Diseases
The link between particulate matter (PM) exposure and poor respiratory health is well
established. Through Aim 3 of Project 1, the LSU Superfund Research Center postulates that
environmentally persistent free radicals (EPFRs) from hazardous waste sites,
incinerators/chemical fires, and other sources is the missing mechanistic link between PM
exposure and poor respiratory health. We will investigate the mediation of this association using
hierarchical mediation analysis to decompose the air pollutant adverse respiratory effects into
direct and indirect (EPFR-mediated) effects.
We developed a multilevel mediation analysis method that allows for both longitudinal
assessments of residential environments and individual risk factors to be jointly utilized in
determining the mechanistic link between exposure to PM and poor respiratory health. By
including measures of individual behavioral factors our methods are capable of explaining
existing disparities in health outcomes.
We have implemented our method as an R package (mlma) to provide the research community
with open access to software for performing multilevel hierarchical mediation analysis. However,
use of our R package does require knowledge of R, which limits its broader use in research. To
address this limitation, we propose to collaborate with a software engineer at LSU to create an
API for an interactive web implementation of our mediation software. We expect that this would
greatly expand access to our methods, as no programming will be required. The proposed app,
with its intuitive interactive visual interface, will allow users to easily read in datasets and build a
conceptual mediation model framework using drag-and-drop functionality. We will also provide
graphical tools such as directed acyclic graphs to allow users to visually interpret the analysis
results. In addition, we will transform part of the computing to an efficient low-level computer
language to improve computational speed and plan to use cloud computing resources so that R
and associated software packages do not have to be installed on individual computers to
perform the analysis.

## Key facts

- **NIH application ID:** 10403859
- **Project number:** 3P42ES013648-09S2
- **Recipient organization:** LOUISIANA STATE UNIV A&M COL BATON ROUGE
- **Principal Investigator:** Stephania A Cormier
- **Activity code:** P42 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $226,970
- **Award type:** 3
- **Project period:** 2021-09-02 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10403859

## Citation

> US National Institutes of Health, RePORTER application 10403859, NOSI to Support Enhancement of Software Tools for Multilevel Mediation Analysis for Investigating Effects of Environmental and Individual Risk Factors on Respiratory Diseases (3P42ES013648-09S2). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10403859. Licensed CC0.

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