Impact Of Age On The Association Between 24-H Ambulatory Blood Pressure Measurements And Target Organ Damage

Objective:The aim of this study was to evaluate the impact of age on the associations between hemodynamic components derived from 24-h ambulatory blood pressure (24-h ABPM) and target organ damage, in apparently healthy, nonmedicated individuals.Methods:Twenty-four-hour ABPM and target organ damage (left ventricular mass index, pulse wave velocity, urine albumin:creatinine ratio and carotid atherosclerotic plaques) were evaluated in 1408 individuals. Associations were examined in regression models, stratified for age [middle-aged (41 or 51 years) or elderly (61 or 71 years)], and adjusted for sex, smoking status, and total-cholesterol.Results:In middle-aged individuals, an increase of 10mmHg in 24-h SBP was independently associated with an increase of 3.8 (2.7-4.8)g/m(2) in LVMI. The effect was nearly doubled in the elderly subgroup, where the same increase resulted in an increase in LVMI of 6.3 (5.0-7.6) g/m(2) (P for interaction <0.01). An increase of 10mmHg of 24-h SBP was associated with a 6.7% increase in pulse wave velocity in middle-aged individuals and with an 9.1% increase in elderly individuals (P for interaction <0.01). An independent association between 24-h ABPM and urine albumin:creatinine ratio was only observed in the elderly subgroup. Associations between the presence of atherosclerotic plaques and components from 24-h ABPM except 24-h DBP were not modified by age (all P for interaction >0.26).Conclusion:Age enhances the associations between hemodynamic components obtained from 24-h ABPM and measures of arterial stiffness, microvascular damage, and cardiac structure, but not atherosclerosis.