Abstract 15901: Neither Ultraviolet B Light Nor PM2.5 Air Pollution Explain the Association Between Higher Altitude of Residence and Better Outcomes After Myocardial Infarction
Background: Prior studies found a link between higher altitude of residence and lower mortality from coronary artery disease that persists after accounting for differences in risk factors and socioeconomic status. Putative explanations include differences in ultraviolet B light-associated vitamin D levels or air pollution.
Methods: In a population-based cohort of incident myocardial infarction (MI) in Alberta, Canada, we tested whether differences in ultraviolet B light or fine particulate air pollution (PM2.5) explain the association between higher elevation of residence and better outcomes. Cases were identified using administrative data by ICD codes 410, I21, and I22. Location of residence was ascertained by six-character postal code, and linked to environmental variables, including altitude of residence, using ArcGIS 10.0. Socioeconomic variables, including median income, employment type and education level, were ascertained by linking subject postal code to Statistics Canada 2006 census dissemination area. Erythemally weighted ultraviolet B irradiance was ascertained using data from the OMI/Aura NASA Satellite, and PM2.5 air pollution was ascertained using data from the MODIS/MISR NASA Satellites. The population was stratified by altitude of residence into quartiles, with the lowest quartile the reference. Logistic regression was used to calculate odds ratios for death or hospital readmission for MI at 30 days and 1 year, and tests for trend across quartiles were performed.
Results: A total of 33,893 cases of incident MI were identified between April 1, 1999 and December 31, 2008, spanning altitudes between 210-2,164 metres. There was a significant trend across quartiles for lower odds ratio for death or readmission for MI at both 30 days and 1 year (p < 0.05). After adjustment for age, sex, comorbidities, socioeconomic variables, ultraviolet B light, and PM2.5 air pollution, the odds ratios for the highest altitude quartile were 0.80 (95% CI 0.72-0.88) for death or readmission at 30 days, and 0.82 (95% CI 0.76-0.88) for death or readmission at 1 year.
Conclusion: The association between higher altitude of residence and better outcomes from coronary artery disease is not explained by differences in ultraviolet B light or PM2.5 air pollution.
- © 2013 by American Heart Association, Inc.