Attenuated age-related increases in arterial stiffness in Japanese and American women

Background The United States and Japan have similar standards of living, healthcare systems, and industrializations but exhibit markedly divergent life expectancies both at birth and at later ages (50 or 65 years old). Arterial stiffness has been widely regarded as a barometer of biological or physiological aging and could provide insight into the inter-country differences. Objectives To determine whether the increases in arterial stiffness across the adult age range are greater in U.S. than Japanese adults. Design Cross-sectional analyses. Setting Laboratory-based study. Participants Healthy, nonsmoking Japanese (n = 400) and U.S. (n = 400) adults without cardiovascular and other chronic diseases. Measurements Indices of arterial stiffness, including carotid-femoral (cfPWV) and brachial-ankle pulse wave velocity (baPWV) were measured, along with a variety of ancillary measures. The recruitment method, measurement technique, and protocol were standardized and identical between U.S. and Japanese facilities. Results cfPWV and baPWV increased progressively with advancing age in all subgroups (stratified according to sex and country). The rates of age-related increases in arterial stiffness were not different between U.S. and Japanese men, but age-associated increases in cfPWV were significantly greater in U.S. than Japanese women, widening the intercountry differences at older age ranges. Conclusion Japanese women had smaller increases in central arterial stiffness with advancing age than U.S. women.