Correlation coefficients between altitude and mortality rates for diseases of the respiratory system, pneumonia, and chronic lower respiratory disease and adjusted R<sup>2</sup> values for multivariate linear regression models with or without altitude for counties with high COPD prevalence (>13%).

<p>Correlation coefficients between altitude and mortality rates for diseases of the respiratory system, pneumonia, and chronic lower respiratory disease and adjusted R<sup>2</sup> values for multivariate linear regression models with or without altitude for counties with high COPD prevalence (>13%).</p>