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.
Majane
Olebogeng H I
OH
Cardiovascular Pathophysiology and Genomics Research Unit, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
Woodiwiss
Angela J
AJ
Maseko
Muzi J
MJ
Crowther
Nigel J
NJ
Dessein
Patrick H
PH
Norton
Gavin R
GR
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