An ecological analysis of childhood-onset type 1 diabetes incidence and prevalence in Latin America

Objective. To explore, for Latin America, by means of an ecological correlation analysis, the possible relationships between both the incidence and prevalence of childhood type 1 diabetes and selected hypothesized etiological factors, including race/ethnicity, geographical latitude, breastfeeding rates, per capita milk supply and coffee consumption, and wealth-related indicators such as infant mortality rate, life expectancy at birth, and national human development index. Methods. Recently published data on incidence and prevalence of type 1 diabetes in children 14 years of age in Latin American countries were utilized. Risk indicators were selected based on existing genetic and environmental hypotheses. Indicator data were obtained from publicly available resources. Spearman correlation coefficients were used to measure the association between both incidence and prevalence of type 1 diabetes and the selected indicators. Results. A strong negative correlation was found between the proportion of Amerindians in a country's population and both incidence (r = -0.75; P = 0.008) and estimated prevalence (r = -0.78; P < 0.0001) of childhood type 1 diabetes. The per capita supply of milk showed a strong positive correlation with both incidence (r = 0.70, P = 0.025) and prevalence (r = 0.55; P = 0.018). Wealth-related indicators correlated with prevalence but not with incidence. Conclusions. Our results suggest that the presence of the Amerindian component of the population in Latin America provides protection against childhood-onset type 1 diabetes. Our results also confirm the association previously reported in other countries and regions of the world of type 1 diabetes and milk consumption. Further studies are needed to develop and test potential genetic and environmental hypotheses that could help to better understand the interplay between genetic susceptibility and environment in type 1 diabetes across different ethnic groups.