Altitude and type 2 diabetes mellitus: an inverse ecological association across two representative Andean populations

Aim: To evaluate the association between residential altitude and the prevalence of type 2 diabetes mellitus (T2DM) in two Andean countries, exploring whether chronic exposure to high-altitude environments confers protection against T2DM. Methods: We conducted a binational ecological study using nationally representative data from Peru (2019 Demographic and Family Health Survey n = 26,593) and Colombia (healthcare registry data, n = 6,223,542). Altitude of residence was categorized into four groups in Peru (<1,500 m, 1,500–2,499 m, 2,500–3,499 m, ≥3,500 m) and three in Colombia (<1,500 m, 1,500–2,499 m, ≥2,500 m). Multivariable logistic regression models estimated adjusted odds ratios (ORs) for T2DM, controlling for sociodemographic and behavioral covariates. Results: An inverse association was observed between altitude and T2DM prevalence in both countries. In Peru, living at 2,500–3,499 m was associated with the lowest odds of T2DM (OR = 0.65 [95 % CI: 0.51–0.82]). In Colombia, residence at ≥ 2,500 m also showed protective associations (OR = 0.639 [95 % CI: 0.636–0.643]) Conclusions: Consistent findings across two national settings support an inverse relationship between altitude and T2DM prevalence. These results suggest that physiological adaptations to chronic hypoxia may reduce diabetes risk, warranting further investigation into underlying mechanisms.