FIGURE 1.

Map of inverse distance weighted interpolation showing the PiZZ/COPD ratio (1/x) in 20 European countries. PiZZ refers to the number of individuals aged ≥40 years, after applying a correction factor of 60% of genetic penetrance. COPD refers to the total number of patients aged ≥40 years from each country. The colour scale corresponds to the prevalence of PiZZ in the total COPD (1/x) of each country. Countries without data are shaded pale green. Unpopulated or sparsely populated regions (with less than two inhabitants per square kilometre) are shaded white. PiZZ: α₁-antitrypsin protease inhibitor ZZ. n=total number points with known values in IDW interpolation (12 for the current map); p=power parameter (p=2 for the current map); res=resolution (0.05 for the present map).