Impact of age on the association between 24-h ambulatory blood pressure measurements and target organ damage.

ABSTRACT

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 10 mmHg in 24-h SBP was independently associated with an increase of 3.8 (2.7-4.8) g/m 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 (P for interaction <0.01). An increase of 10 mmHg 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.