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.


CONCLUSIONS
In women of African ancestry, a greater independent effect of adiposity on PWV is noted in older as compared to younger women.
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Olebogeng H I
OH
Majane
Angela J
AJ
Woodiwiss
Muzi J
MJ
Maseko
Nigel J
NJ
Crowther
Patrick H
PH
Dessein
Gavin R
GR
Norton
D050154:Adiposity; D000328:Adult; D017677:Age Distribution; D000375:Aging; D001011:Aorta / Q000502:physiology; D044383:Black People / Q000706:statistics & numerical data*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D001916:Brachial Artery / Q000502:physiology; D003920:Diabetes Mellitus / Q000208:ethnology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000208:ethnology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000208:ethnology* / Q000503:physiopathology; D015995:Prevalence; D011673:Pulsatile Flow; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D049629:Waist-Hip Ratio