Abstract 13719: Minimal and Delayed Age-Related Increase of Arterial Stiffness Among Tsimane Forager-Horticulturalists

Background: Tsimane forager-farmers of the Bolivian Amazon exhibit a distinct trajectory of vascular aging, characterized by low age-related increases in BP, the lowest levels of coronary calcification ever reported, and robust VO ₂ max. However, the prevalence of arterial stiffness (ArSt) in this population and its association with age and other cardiovascular risk factors are unknown.

Methods: Large artery elasticity (LAE) and small artery elasticity (SAE) were measured among 491 Tsimane adults (mean age 55.3±13.0 y, 55% female) using HDI CR-2000 (Eagan, MN). Carotid-femoral pulse wave velocity (cfPWV) was assessed among 89 Tsimane (mean age 53.1±15.7 y, 54% female) using the foot-to-foot method with ECG and carotid/femoral pulse wave data.

Results: Compared to previous studies from diverse urban populations, Tsimane show lower indices of ArSt: higher LAE (mean 22.79±12.21 ml/mmHg·10) and SAE (mean 7.57±4.04 ml/mmHg·100), and lower cfPWV (mean 6.34±2.1 m/s). LAE and SAE are 73% and 57% higher for Tsimane men, and 70% and 86% higher for Tsimane women, compared to age-matched US MESA adults. Tsimane demonstrate lower LAE and SAE with age, while higher cfPWV was only evident among Tsimane over 70 years (β=2.26±0.71, P =0.001; reference <40 y). Hypertension is rare in this population, but was associated with having higher ArSt.

Conclusion: Tsimane forager-farmers have substantially lower levels of ArSt and fewer age-related differences in ArSt compared to more urbanized and sedentary populations. The minimal and delayed age-related increase of arterial stiffness might contribute to the very low observed levels of coronary atherosclerosis and dementia in the Tsimane.