Arterial Stiffness in Heart‐Healthy Indigenous Tsimane Forager‐Horticulturalists

Background Little is known about arterial stiffness in rural subsistence populations that experience few cardiovascular risk factors. We conducted a cross‐sectional study comparing 3 arterial stiffness metrics among Tsimane forager‐horticulturalists with 2 representative US cohorts. Methods Arterial elasticity (the inverse of stiffness) markers C1 (large artery elasticity) and C2 (small artery elasticity) were measured using a tonometry device among 490 Tsimane adults (mean age, 51.2±10.1 years; 55% women), and compared with 6294 multiethnic US adults (mean age, 62.0±10.2 years; 52% women) from MESA (Multi‐Ethnic Study of Atherosclerosis). Carotid‐femoral pulse wave velocity was assessed using the foot‐to‐foot method in a smaller Tsimane sample (n=94) and compared with 3086 predominantly White US adults (mean age, 46.1±8.7 years; 54% women) from the FHS Gen3 (Framingham Heart Study Third Generation). Results Tsimane participants exhibited superior arterial health compared with US cohorts, with higher elasticity (C1/C2) and lower stiffness (carotid‐femoral pulse wave velocity). Their C1 (mean 22.8±12.2 mL/mm Hg×10) and C2 (mean 7.5±4.0 mL/mm Hg×100) were 47.3% and 35.7% higher than MESA participants by age 40 years, respectively, and differences remained sustained throughout adulthood. Compared with participants in FHS Gen3, the carotid‐femoral pulse wave velocity in Tsimane participants (mean 6.2±1.2 m/s) was 33.9% lower and showed a minimal age‐related increase, with carotid‐femoral pulse wave velocity only higher by age 70+ (β=1.74±0.38; reference <40 years). Tsimane participants with ≥2 comorbidities (hypertension, obesity, and diabetes) had ≈25% higher arterial elasticity than healthy Americans with no comorbidities. Conclusions Tsimane forager‐farmers of the Bolivian Amazon demonstrate substantially lower arterial stiffness throughout adulthood than more urbanized and sedentary populations, and the differences are only partially explained by conventional cardiometabolic risk factors.