Relationships between new risk factors and circadian blood pressure variation in untreated subjects with essential hypertension

Abstract

Recently a growing amount of interest has been focused on new risk factors for cardiovascular disease, such as insulin, leptin, homocysteine, and urinary albumin excretion (UAE). Furthermore, the absence of a nocturnal blood pressure (BP) decrease is emerging as an index for future target organ damage. In the present study we aimed to determine the relationship between these risk factors and circadian BP variations in essential hypertensive subjects. One hundred six patients, aged 54+/-7 years, with stage I-II untreated hypertension were classified as dippers and nondippers according to the diurnal variation of >10% between mean daytime and nighttime systolic BP (SBP) and diastolic BP (DBP) in 24-h noninvasive ambulatory BP monitoring. Venous blood samples were drawn for determination of insulin, leptin, and homocysteine plasma levels, whereas UAE was evaluated in three consecutive 24-h urine samples. Nondippers compared to dippers had significantly greater hemodynamic load and higher UAE (by 17 mg/24 h, P < .05). The two groups did not differ regarding serum insulin, plasma leptin, and homocysteine levels. In the entire population, leptin was positively correlated with age, body mass index, 24-h DBP, fasting serum insulin, and plasma homocysteine levels, whereas homocysteine levels were significantly related to 24-h SBP and DBP values. Multiple linear regression analyses revealed that only UAE was significantly related with nocturnal SBP and DBP decrease (P < .05 for both). These findings suggest that the increased UAE observed in nondipper hypertensive subjects possibly represents a useful indicator-for future target organ damage.