Arterial elasticity in American Indian and Caucasian children, adolescents, and young adults.

We compared arterial elasticity in American Indian and Caucasian children, adolescents, and young adults, and we assessed whether demographic, body composition, and ambulatory activity measures were predictive of arterial elasticity within each group. Fifty-one American Indians and 66 Caucasians between the ages of 8 and 30 years were assessed on large artery elasticity index, small artery elasticity index, body fat percentage, and daily ambulatory activity during 7 consecutive days. American Indians had a higher percentage of body fat than Caucasians (p = 0.002), whereas daily ambulatory activity measures were similar (p > 0.05). American Indians had a 16% lower large artery elasticity index (p = 0.007) and a 19% lower small artery elasticity index (p < 0.001) than Caucasians. The regression model for large artery elasticity index included average cadence (p = 0.001), fat-free mass (p < 0.001), age component (Caucasian only) (p < 0.001), and sex (p = 0.025). The regression model for small artery elasticity index included fat-free mass (p < 0.001), maximum cadence for 30 continuous minutes (p = 0.009), race (p = 0.005), and average cadence (p = 0.049). Between 8 and 30 years of age, elasticity means for the large and small arteries is lower in American Indians than in Caucasians. A smaller difference was observed in children, with a trend to a much larger difference in young adults. Furthermore, greater fat-free mass and higher daily ambulatory cadence are associated with higher arterial elasticity in both American Indians and Caucasians.