An ecological study of allergy epidemiology in Spain: a 25-year time series research: Quantitative statistics supporting the allergy growth

Background: Allergic illnesses are among the most common causes of chronic pathology, and their incidence is thought to be growing for several years. It is intriguing to do ecological studies using aggregated data, taking into consideration social and economic elements, which are sparse, particularly among adults. Methods: An ecological cross-sectional observational study was carried out utilizing anonymized and aggregated data from the National Health Survey. The data used are from 1993, 1995, 1997, 2001, 2003, 2006, 2009, 2011, 2014, and 2017 (a 25-year period). Descriptive statistics on the evolution of allergy prevalence were acquired, as well as potential contributing factors (social, demographic, economic, etc.). The statistics comprised measurements of central position (mean, median), dispersion (standard deviation, variance, coefficient of variation), distribution (ranges, maximum and lowest values, skewness and kurtosis), normality tests, significance tests, and multivariate analysis. Results: The prevalence of allergies in Spain has increased significantly (more than 50%). The growth has been consistent across all age and gender categories, although it has been particularly noticeable among young women. Furthermore, populations with more than 400,000 people have the highest prevalence, as do those with higher incomes and educational levels.Conclusion: We have quantifiable data that supports the continuing increase of allergies and links it to societal factors (younger individuals, women, higher income and education levels).