Objectives: To assess cognition in populations born and living at high altitude (HA; 3,700 m) and low altitude (LA; 500 m) in Bolivia, who were similar for both socioeconomic status and genetic ancestry. To determine whether HA hypoxia influences cognitive decline across the life span. Method: In total, 191 healthy participants aged 4 to 85 years were assessed at HA (N = 94; 33; 35% male) and LA (N = 97; 46, 47% male) on a battery of cognitive tasks: fluid intelligence, attention, short- and long-term memory, and psychomotor speed. Saliva samples were obtained for evaluation of genetic ancestry. Results: HA participants were significantly slower on measures of processing speed and speed of attention than individuals born and living at LA. HA participants had slightly higher percentage of native Andean ancestry than LA participants, but this was not associated with cognitive performance. Conclusions: This is the first study of HA residence and neurocognition across the life span. Given the physiological challenges of HA living, the impact on cognition appears to be subtle and related only to the speed of more complex cognitive operations, rather than to their accuracy. Moreover, the impact on cognition does not appear to differ with increasing age or for different degrees of genetic admixture. Further studies recruiting HA participants with a broader range of native Andean ancestry will help to address the issue of to what extent Amerindian ancestry provides neuroprotection to chronic hypoxia in those living at HA.
