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Abstract

Grant Number:	1R01OH007429-01
Project Title:	Silica Exposure & Silicosis: Effect of Mixed Exposures

PI Information:	Name	Email	Title
	RAMACHANDRAN, GURUMURTHY	ramac002@umn.edu	PROFESSOR

Abstract: DESCRIPTION (provided by applicant): The quantitative relationship between exposure to crystalline silica and development of silicosis is uncertain despite a number of studies. The uncertainty is due to the following reasons: (a) exposure reconstructions are typically based on sparse data with significant uncertainty; (b) dose reconstructions that obtain the cumulative lung burden of the worker, do not account for simultaneous exposures to less toxic dusts, categorized as particles not otherwise classified (PNOC). The purpose of this study is to obtain the quantitative dose-response relationship between crystalline silica and silicosis in a manner that addresses the above three issues. The North Carolina Dusty Trades program, provides a large data set of human exposures to silica and PNOC and silicosis cases from 1935-1980 for this purpose. A novel Bayesian methodology that synthesizes expert judgment, exposure models, and historical measurements will be used for exposure reconstruction. Pharmacokinetic modeling will be used to estimate the cumulative lung does of silica and PNOC, and PNOC, and the time to macrophage overload in this mixed exposure scenario. A case-control study will be conducted to compare silicotics and disease free referents and test the following hypotheses: (1) A cumulative exposure metric, which includes both silica and PNOC, is more related to the development of silicosis than cumulative silica exposure alone, (2) The time to macrophage overload is shorter among cases than non-cases employed in the dusty trades, (3) The time to macrophage overload, due to exposures to mixtures of silica and PNOC, is related to the time from first exposure to disease among silicosis cases.

Public Health Relevance:
This Public Health Relevance is not available.

Thesaurus Terms:
disease /disorder proneness /risk, environmental exposure, environmental toxicology, mathematical model, model design /development, pneumoconiosis, respiratory disorder epidemiology, silicate
clearance rate, dust, longitudinal human study, macrophage, particle, pathologic process, pharmacokinetics, respiratory airway clearance
clinical research, computer data analysis, human data, statistics /biometry

Institution:	UNIVERSITY OF MINNESOTA TWIN CITIES
	450 MCNAMARA ALUMNI CENTER
	MINNEAPOLIS, MN 554552070
Fiscal Year:	2001
Department:	ENVIRONMENTAL HEALTH SCIENCES
Project Start:	30-SEP-2001
Project End:	29-SEP-2003
ICD:	NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH
IRG:	ZRG1

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