Influence of aging and other cardiovascular risk factors on baroreflex sensitivity

To examine the influence of known cardiovascular risk factors (cholesterol, blood glucose levels, arterial pressures, heart rate, and aging) on baroreflex sensitivity.

An observational epidemiological study.

Geriatric Division at the Policlinico Umberto Primo, University of Rome La Sapienza.

Two hundred three subjects whose ages ranged from 9 to 94 years, apparently healthy and free of detectable clinical evidence of atherosclerosis.

All subjects underwent determination of baroreflex sensitivity by phenylephrine infusion (BSphe), and by a noninvasive method derived from spectral analysis of R-R interval and arterial pressure variabilities (alpha index).

The population, subdivided into tertiles for each variable studied, had lower BSphe values and lower alpha indexes as a function of age, plasma low-density lipoprotein (LDL) cholesterol, and systolic blood pressure. The alpha index was significantly lower in both groups with elevated LDL cholesterol levels than in those with lower levels (II and III vs I tertile, P <.001), whereas BSphe differed significantly only in the two groups who had extreme levels of LDL (I vs III tertile, P <.001). Multiple regression analysis identified a negative association of the alpha index with age (P <.001), heart rate (P <.01), area under the glucose-response curve (P <.001), and LDL cholesterol (P <.01), but of BSphe only with age (P <.001) and heart rate (P <.01).

These findings indicate that some risk factors for coronary heart disease adversely influence baroreflex sensitivity.