... percentage Hispanics, and number of tobacco outlets. Further, inverse relationships were found between the incidence of COPD charges and income level and the percentage of the population with undergraduate ... superimposing them over other features, and determining the extent to which there was overlap between the grid and a spatial unit–in this instance, the Int. J. Med. Sci. 2007, 4 182degree of overlap ... position as the fourth leading cause of death in the U.S. and world-wide [2, 3, 4]. Approximately 120,000 adults (25 years of age and older) died from COPD in 2000 in the US. Although the COPD...