Attenuated Age-Related Increases in Arterial Stiffness in Japanese and American Women

BackgroundThe 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 65years old). Arterial stiffness has been widely regarded as a barometer of biological or physiological aging and could provide insight into the inter-country differences. ObjectivesTo determine whether the increases in arterial stiffness across the adult age range are greater in U.S. than Japanese adults. DesignCross-sectional analyses. SettingLaboratory-based study. ParticipantsHealthy, nonsmoking Japanese (n=400) and U.S. (n=400) adults without cardiovascular and other chronic diseases. MeasurementsIndices 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. ResultscfPWV 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. ConclusionJapanese women had smaller increases in central arterial stiffness with advancing age than U.S. women.