Blood pressure level increase with altitude in three argentinean indigenous communities

Objective: To compare blood pressure (BP) levels in three groups of Argentinean Indigenous schoolchildren from similar ethnic backgrounds but living at three different altitudes. Methods: A cross-sectional study compared 185 (83 females) children aged 5-14 years from San Antonio de los Cobres (SAC), 3750 m above sea level; 46 (23 females) from Cobres, 3450 m; and 167 (83 females) from Chicoana (CH), 1400 m. Anthropometric and BP measurements were performed. Results: The prevalence of overweight/obesity was lower in SAC (6.5% [12]) and Cobres (4.3% [2]) than in CH (24% [24]) (BMI > 85 percentile per CDC norms). Systolic BP increased significantly with altitude: (SAC 86 mm Hg, Cobres 77 mm Hg, and CH 69 mm Hg). Similar results were obtained with diastolic BP (SAC 57 mm Hg, Cobres 51 mm Hg, and CH 47 mm Hg) and with median arterial pressure (MAP) (SAC 67 mm Hg, Cobres 60 mm Hg, and CH 55 mm Hg). Multiple linear regression analyses showed that altitude was significantly and independently associated with children's systolic BP (beta 10.56; R-2 = 0.40), diastolic BP (beta 6.27; R-2 = 0.25) and MAP (beta 7.69; R-2 = 0.32); adjusted for age, sex, and BMI. Conclusions: We found that as altitude increased, BP levels increased significantly in indigenous children from similar backgrounds living permanently at different altitudes.