ABSTRACT
When we initiated our non-invasive clinical studies in the late 1970s to complement earlier invasive human and animal experimental studies, we confirmed the very substantial changes with age in humans which were not seen in experimental animals (O’Rourke et al., 1968; Nichols et al., 1977b; O’Rourke, 1982b) and attributed them to arterial disease (atherosclerosis) which accompanies aging. The opportunity then arose in the early 1980s to repeat these studies on pulse wave velocity (PWV) in mainland Chinese populations in regions with known high and low prevalence of hypertension. We were surprised to find in the former group, increase in aortic PWV similar to what we and others had recorded in Western populations with high prevalence of atherosclerosis, despite the Chinese group having virtually no evidence of atherosclerosis, and having low blood cholesterol levels (Ho, 1982; Avolio et al., 1983). The Chinese group with low prevalence of hypertension (in rural Guangdong province) also showed increased aortic stiffening with age, but this, while beginning at the same level in childhood, was less than in the other group from urban Beijing in later life (Avolio et al., 1985a; Avolio et al., 1986; Avolio, 2003). There was a substantial difference in salt intake between the two Chinese groups, and this was considered to be responsible for the different prevalence of hypertension (Wu et al., 1996). It may primarily have been responsible also for increased aortic stiffness in the urban Beijing population. We concluded that the aorta and elastic arteries progressively stiffen with age, and that this is accelerated by hypertension and high salt intake (Avolio et al., 1985a). Studies of aortic structure in the Chinese groups were subsequently undertaken and confirmed similar aging change in China, the United States, and Australia (Virmani et al., 1991) and supported our previous morphometric studies (Nichols et al., 1985a; O’Rourke et al., 1987). We concluded that atherosclerosis has little effect
per se on aortic stiffening with age, but that salt had an important adverse effect.
