In this study the prevalence of the Pi * SZ genotype is estimated worldwide, statistics in studies of previous populations. 262 cohorts from 71 countries are included for analysis. The allowed data from these cohorts allow estimating the existence of almost 1,500,000 Pi * SZ individuals worldwide, the majority (48%) in Europe, 39% in America and 13% in Australia and New Zealand.
The Iberian peninsula (especially Portugal and northwest Spain, including Galicia) is an area with a very high prevalence of this genotype. It is estimated a prevalence of 1: 205 inhabitants in Portugal (the highest in the world) and 1: 278 in Spain. In our country it has around 175,000 carriers of the Pi * SZ genotype.
Given the levels of alpha 1 antitrypsin expressed by Pi * SZ individuals, up to 10% of them may develop emphysema, especially if they have a history of smoking. Based on these data, at least 150,000 Pi * SZ cases would be at risk of developing COPD.