High altitude is not a risk factor for type 2 diabetes mellitus

Bernabé-Ortiz et al. [1] state that “individuals living at high altitude are at greater risk of incident diabetes”. They propose that lower forced vital capacity (FVC), lower birth weight, childhood chronic undernutrition or shorter adult stature may explain this observation. On the contrary, a series of studies [2–5] have shown that chronic exposure to high altitude is related to increased insulin sensitivity. This physiological state explains in part the inverse association between high altitude and diabetes, confirmed in a recent study, by Woolcott in the USA [6], which finds an odds ratio of 0.88 for type 2 diabetes in those living between 1500 and 3500 meters above sea level