Impact of Age on the Independent Association of Adiposity With Pulse-wave Velocity in a Population Sample of African Ancestry

BACKGROUND: We aimed to clarify whether age influences the independent relationship between adiposity and pulse-wave velocity (PWV). METHODS: We explored the effect of age on the independent relationships between indexes of central adiposity (waist circumference (WC) and waist-to-hip ratio (WHR)) and carotid-femoral PWV, central augmentation index (AIc), or pressure wave amplification assessed from applanation tonometry measurements obtained at the radial, carotid, and femoral arteries in 508 randomly selected subjects >16 years of age in a population sample of African ancestry with a high prevalence of excess adiposity ( approximately 63% overweight or obese). RESULTS: In women a strong interaction between age and either WC or WHR was associated with logPWV independent of confounders and the individual terms (r = 0.68, P < 0.0001). This translated into a markedly greater increase in logPWV with increases in either WC or WHR in women older than the median age as compared to women younger (slopes of WC-logPWV relationships = 0.0031 +/- 0.0009 vs. -0.0007 +/- 0.0007, P < 0.002). In women older than the median age for the group, a one s.d. increase in WC (12.8 cm) translated into a 0.70 m/s increase in PWV as compared to a 0.14 m/s decrease in PWV for each one s.d. increase in WC (13.0 cm) in women younger than the median age (P < 0.001). No index of adiposity was independently associated with the log of AIc or aortic-brachial wave amplification. CONCLUSION: In women of African ancestry, a greater independent effect of adiposity on PWV is noted in older as compared to younger women.