High Altitude as a Cause of Congenital Heart Defects: A Medical Hypothesis Rediscovered in Ecuador

Gonzalez-Andrade, Fabricio. High altitude as a cause of congenital heart defects: a medical hypothesis rediscovered in Ecuador. High Alt Med Biol. 00:000-000, 2020. Background: There are similar to 83 million people living at high altitude (>2500 m) worldwide who endure chronic hypoxia conditions. This article aims to analyze the relationship between high altitude, identified in several cities in Ecuador, and the prevalence of congenital heart disease (CHD). Methods: Set in Ecuador, this epidemiological observational cross-sectional study analyzes data over a range of 18 years (from 2000 to 2017), including 34,904 reported cases of CHD, with a mean of 1939 cases per year. Results: The mean prevalence rate of CHD found is 70.6 per 10,000 live newborns. A K-means analysis resulted in three clusters. Cluster 1 shows the lowest altitude and prevalence of CHD, with an average of 2619 m and 63.02 cases per 10,000 live newborns. Cluster 2 presents the second highest altitude and prevalence of CHD, with an average of 2909 m and 72.04 cases per 10,000 live newborns. Cluster 3 shows the highest values of altitude and prevalence of CHD, with an average of 3176 m and 86.62 cases per 10,000 live newborns. Pearson's coefficient is 0.979, so the correlation between the variables is positive. An altitude ranging from 2500 to 2750 m relates to a prevalence of CHD of <= 71 cases per 10,000 live newborns. An altitude ranging from 2751 to 3000 m relates to a prevalence of CHD of >71 and <89 cases per 10,000 live newborns. An altitude ranging between 3001 and 3264 m relates to a prevalence of CHD of >= 89 cases per 10,000 live newborns. Conclusions: The findings show that high altitude (>2500 m), ethnicity (Native American), rural locations, and limited access to health care are factors that influence and increase the prevalence rate of CHD. A correlation coefficient of 0.914 shows the direct relationship between high altitude and prevalence rates of CHD. For each year elapsed, the prevalence of CHD increased by 3.33 cases per 10,000 live newborns.