2012 Progress Report: Are Diabetics and the Neurologically Impaired at Increased Risk from Air Pollutant Exposures? A National Analysis

EPA Grant Number: R834900
Title: Are Diabetics and the Neurologically Impaired at Increased Risk from Air Pollutant Exposures? A National Analysis
Investigators: Zanobetti, Antonella , Dominici, Francesca , Koutrakis, Petros , Schwartz, Joel , Wang, Yun
Institution: Harvard T.H. Chan School of Public Health , The Johns Hopkins University
Current Institution: Harvard T.H. Chan School of Public Health
EPA Project Officer: Ilacqua, Vito
Project Period: April 1, 2011 through March 31, 2014 (Extended to March 31, 2015)
Project Period Covered by this Report: April 1, 2012 through March 31,2013
Project Amount: $299,903
RFA: Exploring New Air Pollution Health Effects Links in Existing Datasets (2010) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Health Effects , Air

Objective:

We focused this project on two susceptible populations: individuals with neurological disorder, and individuals with diabetes. Using Medicare data to select the susceptible populations, we will estimate county-specific mortality risks associated with both short- and long-term exposure to individual pollutants on a national scale. Then we will identify factors that could explain the heterogeneity of these air pollution mortality risks. The specific aims of this proposal are to:

Aim 1: Estimate the chronic effects on mortality of long-term exposure to individual pollutants in several U.S. counties in two susceptible populations defined as individuals with neurological disorders or diabetes.

Aim 2: Estimate the acute effects on mortality of short-term effects of individual pollutants in a potentially susceptible population.

Aim 3: Investigate whether markers of susceptibility and vulnerability differentially influence the previously established relationships between individual pollutants and mortality, allowing us to identify subpopulations at increased risk for harmful effects of air pollution. Moreover, we will examine the effect of modifications due to the composition of multi-pollutant mixtures and to PM composition.

Progress Summary:

Progress Summary/Accomplishments/Expected Results:        

First, we worked on preparing the data (see points 1 and 2). We then started to analyze the data, by first examining the acute effects on mortality of short-term effects of PM2.5 in individuals with neurological disorders and diabetes. (Aim 2)

  1. Medicare data

We updated the dataset to include the years up to 2010. We then created two datasets for all years and communities. In the first, we used the Medicare claims records from the Medicare Provider Analysis and Review (MEDPAR) to identify all Medicare FFS patients who were hospitalized for the targeted medical conditions. The MEDPAR inpatient data include information on patient demographics (age, sex, race), dates of admission and discharge, admission sources and types, principal and secondary diagnosis codes, and procedure codes, defined by the International Classification of Diseases, Ninth Revision (ICD-9).

In the second dataset, we first identified all deaths by selecting those subjects who died among all in the Medicare enrollees denominator file. From the MEDPAR inpatient data, we also identified the five cause-specific hospital admissions prior to death. We then linked the deaths in the Medicare enrollee denominator file with the hospitalizations; we excluded patients who could not be merged with the Medicare denominator file. The medical conditions that we examined were:

  1. Diabetes ICD-9: 250;
  2. Dementia ICD-9: 290
  3. Alzheimer's disease ICD-9: 331.0;
  4. Parkinson's disease ICD-9: 332;
  1. Air pollution, weather, and Census data

We obtained daily air pollution (PM2.5, NO2, CO, and Ozone) from the U.S. EPA Air Quality System website, and weather from the NOAA website. Key variables in the pollution data include monitor ID, date, FIPS, and sample value. Key variables in the weather data include daily temperature (mean, min, max), daily dew point, date, and weather station and WBAN IDs.

Preliminary results: We submitted the following abstract to the ISEE 2013 entitled “A National analysis of the short term effect of PM2.5 on hospitalizations and mortality in subjects with diabetes and the neurological impairment.” I am adding here the abstract which describes our preliminary results.

Background: Short-term exposure to ambient air pollution is associated with mortality and morbidity; diabetes, Parkinson’s disease, dementia, and Alzheimer's disease are also a growing burden.

Aims: To estimate the short-term effects of PM2.5 on (1) hospitalizations for neurological disorders and diabetes, and (2) on mortality in all Medicare deaths and whether the mortality risks associated with PM2.5 among the elderly is modified by neurological disorders or diabetes. 

Methods: We examined hospitalizations and deaths among all Medicare enrollees from 1999-2010 in 121 U.S. cities. We conducted city-specific case-crossover analyses to estimate the short-term effects of PM2.5 on (1) hospitalizations in subjects for neurological disorders and diabetes; (2) all-cause mortality risks for all Medicare deaths, and effect modification by previous admissions for diabetes and neurological diseases.

Results: (1) In the analysis of hospitalizations, we found significant effects of PM2.5 on hospitalization rates for diabetes with a 0.53% increase (95% CI: 0.35-0.71) per 10 mg/m3 increase in the 2 days average of PM2.5; for Alzheimer’s disease (0.42% increase, 95% CI: 0.11-0.72); for Parkinson’s disease (0.79%, 0.34-1.25); and for dementia (0.59%, 0.14-1.04).

(2) We found a 0.64% increase (95% CI: 0.42-0.85) in mortality rate for each 10 µg/m3 increase in the 2 days average of PM2.5 among all Medicare deaths. We found increased mortality risk in subjects with previous admissions for diabetes (0.76%, 0.39-1.12), Parkinson’s disease (1.15%, 0.09-2.23), dementia (0.94%, 0.01-1.89), Alzheimer’s disease (1.04%, 0.36-1.72), and multiple sclerosis (4.01%, -0.03-8.21), but these were not significantly higher than the overall mortality risk.

Conclusions: In this multi-city study, we found that particles increased the risk of mortality and of hospitalizations in subjects with diabetes and neurological disorders.

Future Activities:

We started working on preparing the dataset for survival analysis in around 200 cities across the United States. We will first look at mortality in all Medicare enrollee and then focus on survival in subjects with neurological disorders.

We will also examine vulnerability and susceptibility (Aim 3) in relation to our results of Aim 2 by using FIPS and Zip Code level area characteristics.

We will perform a survival analysis as described in Aim 1, but we will focus on New England, where we predicted daily PM2.5 concentration levels for the years 2000–2008 at a 10×10 km spatial resolution, using satellite-derived aerosol optical depth (AOD) measurements.

We will then focus on other remaining activities outlined in the grant proposal.


Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other project views: All 19 publications 11 publications in selected types All 11 journal articles
Type Citation Project Document Sources
Journal Article Zanobetti A, Dominici F, Wang Y, Schwartz JD. A national case-crossover analysis of the short-term effect of PM2.5 on hospitalizations and mortality in subjects with diabetes and neurological disorders. Environmental Health 2014;13(1):38 (11 pp.). R834900 (2012)
R834900 (2013)
R834900 (Final)
R834798C005 (2014)
R834798C005 (Final)
R834894 (Final)
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  • Supplemental Keywords:

    Health effects, vulnerability, susceptibility, particulates, environmental epidemiology

    Progress and Final Reports:

    Original Abstract
    2011 Progress Report
    2013 Progress Report
    Final Report