Search

OBJECTIVES: Natriuretic peptides control cardiovascular functions through diuretic, natriuretic, and vasodilatory properties. Several anthropometric, cardiac and renal variables were found to be independently correlated to their levels. Few studies, however, systematically investigated the independent determinants of natriuretic peptide levels in large populations. DESIGN: The present analysis was carried out in a large unselected sample of adult male population in Southern Italy (The Olivetti Heart Study, n = 806 men, mean age = 59.5, range 35-82 years). We examined the relationship of plasma natriuretic peptide-proatrial natriuretic peptide (NT-proANP) levels with relevant anthropometric, clinical and biochemical variables; the impact of age; and the association of NT-proANP levels with cardiovascular risk. RESULTS: NT-proANP was directly associated to age, pulse pressure (PP), renal sodium fractional excretion (FENa) (P < 0.005), and inversely to diastolic blood pressure (DBP), heart rate (HR), creatinine clearance, body mass index (BMI), arm and leg circumferences (P < 0.005). After adjustment for age, DBP, creatinine clearance, FENa and HR remained independent determinants of NT-proANP levels (all P < 0.01, cumulative R = 0.186). Upon stratification of our population by tertile of age, NT-proANP was significantly associated (P

BACKGROUND: Because high circulating plasma leptin is associated with many features of the metabolic syndrome (MS), such as abdominal obesity, insulin resistance and high blood pressure (BP), we analysed the ability of plasma leptin concentration to predict the risk of developing MS in a prospective investigation of adult male participants of the Olivetti Heart Study (OHS). METHODS AND RESULTS: Three hundred and sixty out of 907 men participating in the 1994-95 and 2002-04 OHS examinations (mean age at baseline 50.4 years, range 25-73 years) were free of MS at first visit according to NCEP-ATP III criteria (modified for the lack of high-density lipoprotein cholesterol measurement at baseline). During an average follow-up period of 8 years, there were 52 incident cases of MS (14.5%) due, in particular, to a rise in the prevalence of high BP (+42.4%), abdominal obesity (+16.4%) and impaired fasting glucose (IFG, +6.1%). In multivariate analyses, a one standard deviation difference in baseline plasma leptin concentration was associated with a 1.58-fold greater risk of developing MS (95% confidence interval = 1.10-2.30, P = 0.016) accounting for age, waist circumference, homeostatic assessment model index, smoking, alcohol consumption and physical activity. In particular, plasma leptin was positively associated with the risk of developing high BP (0.006) and IFG (0.014), after adjustment for confounders. CONCLUSION: In this sample of an adult male population free of MS at baseline, circulating plasma leptin was a significant predictor of the risk of MS and, in particular, of its high BP and IFG components, independently of potential confounders.

Objective To study the interaction between the C(-344)T CYP11B2 polymorphism and known determinants (age, body mass and dietary sodium) of blood pressure and plasma aldosterone. Design Cross-sectional and longitudinal (1980-1995) survey of male workers in southern Italy. Setting Medical centre of the Olivetti factories. Participants In 1995, the C(-344)T polymorphism was characterized in 811 untreated men. A subgroup of 280 participants already seen in 1980 was the object of longitudinal analysis. Main outcome measures Blood pressure, demographic, anthropometric and biochemical variables (serum and urinary electrolytes and plasma aldosterone) and frequency of the C(-344)T polymorphism. Results In the whole population, there was no difference among genotypes for any of the variables examined. However, multiple regression showed a significant interaction between age (but not body mass or sodium intake) and genotype with regard to systolic (P = 0.03) and diastolic (P= 0.02) pressure variability independently of covariates. Diastolic pressure increased linearly with age in carriers of the T allele (TT, P < 0.001 and TC, P = 0.005), but not in CC homozygotes (P= 0.848). In T carriers - but not in CC homozygotes - blood pressure and serum potassium increased and plasma aldosterone and serum sodium decreased across quintiles of age (P< 0.001 for all trends). In the longitudinal study, diastolic pressure increased significantly over time only in T carriers (TC+TT: +2.6 ± 0.6, versus CC: - 0.4 ± 1.5 mmHg, P= 0.04). Conclusion Inter-individual variation of blood pressure and plasma aldosterone is affected by the interaction of CYP11B2 C(-344)T polymorphism and ageing, thus supporting a role for this variant in mechanisms affecting blood pressure regulation.

A controlled trial of the effect of low versus high calcium intake on blood pressure was performed in 15 patients with mild essential hypertension (supine blood pressure after a 1-month run-in period: 145.7 +/- 2.6/97.8 +/- 0.9 mmHg, mean +/- s.e.m.). After a 1-week baseline period on a standard calcium intake (900 mg/day, obtained by giving a 500-mg calcium tablet daily, in addition to a 400-mg calcium diet), the patients were randomly entered into a double-blind crossover study of 4-week low calcium intake (400 mg calcium diet plus two placebo tablets/day) and 4-week high calcium intake (1400 mg/day: 400-mg calcium diet plus two 500-mg calcium tablets/day). Compliance with the diets appeared to be satisfactory, based on the results of food record analysis. No significant blood pressure change was observed at the end of the low-compared to the high-calcium regimen. Serum ionized calcium was slightly, but not significantly lower, while 24-h urinary calcium excretion was significantly reduced during the low-calcium diet. No difference was found in urinary sodium and potassium excretion between the two study periods. We conclude that moderate modifications of oral calcium intake are not associated with changes in blood pressure within the time span of this study.