摘要:

ObjectiveThe antihypertensive effect of fish oil was estimated from randomized trials using metaregression analysis. Modification of the blood pressure (BP) effect by age, gender, blood pressure, and body mass index was examined.MethodsA total of 90 randomized trials of fish oil and BP were identified through MEDLINE (1966–March 2001). Trials with co-interventions, patient populations, non-placebo controls, or duration of<2 weeks were excluded. A total of 36 trials (50 strata) were included, 22 of which had a double-blind design. Original reports were retrieved for data collection on sample size, study design, duration, fish oil dose, BP changes and baseline characteristics of trial populations. Pooled BP estimates were obtained by metaregression analysis, weighted for trial sample sizes. Stratified analyses according to population characteristics were performed.ResultsIntake of fish oil was high in most trials (median dose: 3.7 g/day). Fish oil reduced systolic BP by 2.1 mmHg [95% confidence interval (CI): 1.0, 3.2;P<0.01] and diastolic BP by 1.6 mmHg (95% CI: 1.0. 2.2;P<0.01). Restricting the analysis to double-blind trials yielded BP reductions of 1.7 mmHg (95% CI: 0.3, 3.1) and 1.5 mmHg (95% CI: 0.6, 2.3), respectively. BP effects tended to be larger in populations that were older (>45 years) and in hypertensive populations (BP ⩾ 140/90 mmHg).ConclusionsHigh intake of fish oil may lower BP, especially in older and hypertensive subjects. The antihypertensive effect of lower doses of fish oil (<0.5 g/day) however, remains to be established.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

ObjectiveTo investigate whether nondipping and diabetes are independently related to metabolic risk profile and prevalence of target organ damage in a population setting.MethodsA population-based cohort of 70-year-old men (n= 1057) was examined with 24-h ambulatory blood pressure monitoring, euglycemic hyperinsulinemic clamp and lipid and glucose determinations. We defined nondipping as a night–day systolic blood pressure ratio⩾1 (n= 66). Urinary albumin excretion rate and echocardiographically determined left ventricular geometry were used as indices of target organ damage.ResultsNondipping was not related to hypertension, but diabetes was more common in nondippers (26%) than in dippers (14%,P<0.05). Nondiabetic nondippers did not differ from dippers regarding insulin sensitivity, plasma glucose or lipids. However, nondipping in diabetic subjects was associated with the most pronounced impairments in body mass index, serum triglycerides and fasting plasma glucose. Measures of target organ damage did not differ between nondippers and dippers in the whole population, but an interaction (P<0.05) between nondipping and diabetes contributed to an increased left ventricular mass in diabetic nondippers. The urinary albumin excretion rate was independently related to diabetes.ConclusionsIn this population study, an interaction between diabetes and nondipping was demonstrated regarding fasting plasma glucose, lipid levels and left ventricular mass, indicating that nondipping is a marker of risk in diabetic subjects. However, in the nondiabetic majority of the population, nondipping was not associated with either metabolic disturbances or target organ damage.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

ObjectiveTo investigate the relationship between blood pressure at 4 min after exercise using a Master's two-step and the risk for hypertension.DesignProspective cohort study.SettingWork site in Osaka, Japan.ParticipantsA total of 6557 Japanese men, aged 35–63 years with systolic blood pressure (SBP)<140 mmHg and diastolic blood pressure (DBP)<90 mmHg, and no history of hypertension or diabetes at baseline.Main outcome measuresBlood pressure was measured by standard techniques, using 160/95 mmHg for diagnosis of hypertension. Normotension was defined as no history of hypertension, and SBP<130 mmHg and DBP<85 mmHg. High normal blood pressure was defined as no history of hypertension and SBP ⩾ 130 and<140 mmHg or DBP ⩾ 85 and<90 mmHg.ResultsDuring the 63 696 person-years follow-up period, we confirmed 660 cases of hypertension. SBP and DBP after exercise were associated with an increased risk for developing hypertension. The multiple-adjusted relative risk for SBP and DBP after exercise were 1.55 per 10 mmHg (confidence interval, 1.42–1.69) and 1.55 per 10 mmHg (confidence interval, 1.42–1.69), respectively. These associations were independent of resting SBP and DBP. Even after stratifying subjects according to blood pressure at rest, SBP or DBP at 4 min after exercise was associated with an increased risk for hypertension in subjects with normotension or high normal blood pressure at rest.ConclusionsThe blood pressure response after exercise with a two-step was associated with an increased risk for hypertension, independently of resting blood pressures.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

ObjectivesInsulin-resistance-associated hepatic iron overload syndrome (IRHIO) is characterized by high serum ferritin and presence of metabolic alterations that are part of insulin-resistance syndrome (IRS). Thus, clinical conditions characterized by a high prevalence of IRS may also be characterized by a high prevalence of IRHIO.Design and methodsWe studied 88 consecutive patients with essential hypertension, 62 patients with IRHIO and 102 healthy normotensive controls. Hemochromatosis, other conditions able to induce secondary iron overload or serum ferritin increase unrelated to body iron stores were excluded. Iron indices, metabolic profiles and hepatic tests in hypertensive with or without increased serum ferritin and in IRHIO with and without hypertension were studied. Metabolic variables, serum iron indices, liver function tests and hepatic ultrasound data were analysed. Data were compared by non-parametric tests.ResultsIn men with hypertension, increased serum ferritin was more frequent than in controls (21 versus 0%,P= 0.001). Hypertensive men with increased serum ferritin had more frequent and pronounced metabolic alterations than those with normal serum ferritin, the metabolic abnormalities and serum ferritin being frequently positively correlated. In hypertensive men with increased serum ferritin, metabolic and iron data were similar to those of IRHIO patients with hypertension.ConclusionsIn males, hypertension is characterized by a higher prevalence of increased iron stores and metabolic abnormalities that are part of the IRHIO syndrome. This finding may have clinical implications due to the increased risk of IRHIO patients to develop hepatic cirrhosis and also for the role of iron in early atherogenesis.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BackgroundClinical decision-making in hypertensive patients is largely based upon assessment of total cardiovascular risk. World Health Organization–International Society of Hypertension (WHO–ISH) guidelines suggest delaying or withholding drug treatment in individuals assessed as at low risk on the basis of a suggested work-up that does not include echocardiography.ObjectiveTo assess the impact of echocardiography on risk stratification in never-treated individuals classified as at low cardiovascular risk.DesignA retrospective analysis of a prospective survey.SettingOutpatient hypertension clinics of three community hospitals.PatientsA total of 792 hypertensive adults classified as at low or medium risk, drawn from a larger sample of 1322 never-treated hypertensive patients.Main outcome measuresChange in risk class and need of immediate treatment after echocardiographic evaluation of left ventricular hypertrophy.ResultsThose at low and medium risk according to WHO–ISH (to receive delayed treatment) represented 17 and 43%, respectively, of the whole hypertensive population. The prevalence of left ventricular hypertrophy on echocardiography was 21 and 32% in low- and medium-risk groups, respectively (29% on average).ConclusionsIn untreated hypertensive individuals without overt target-organ damage, in whom treatment would be postponed or avoided according to current WHO–ISH guidelines, echocardiography modifies the risk classification in 29% of the cases, identifying a need for immediate drug treatment. In low-risk untreated hypertensive individuals, echocardiography commonly alters risk stratification based on the initial WHO–ISH work-up.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

ObjectiveTo compare the relationships of treatment-induced reductions of left ventricular hypertrophy to the changes in clinic and ambulatory blood pressure (BP).DesignDouble-blind and randomized treatment with irbesartan or atenolol for 48 weeks.PatientsPatients with hypertension and left ventricular hypertrophy (n= 66) with a seated diastolic BP 90–115 mmHg (average of three measurements one minute apart by nurses).Main outcome measuresRegistrations of echocardiographic left ventricular (LV) mass. Clinic and ambulatory BP.ResultsIn the total material, nurse-measured BP was reduced by 23±15/16±7.7 mmHg and 24-h ambulatory BP fell 20±15/14±8.5 mmHg by treatment. The correlation between the change in nurse-measured BP and LV mass index (LVMI) induced by treatment wasr= 0.35,P= 0.004 for systolic BP andr= 0.26,P= 0.03 for diastolic BP. Corresponding values for 24-h ambulatory BP werer= 0.29,P= 0.02 andr= 0.35,P= 0.004, respectively, with similar correlations for day- and night-time ambulatory BP. The nurse-recorded BP was slightly higher than ambulatory BP (systolic clinic−systolic 24-h ambulatory BP = 5 mmHg). Using 130/80 mmHg as a cut-off value for normal 24-h ambulatory BP, eight subjects had normal diastolic or systolic ambulatory BP, or both. Interestingly, these patients also experienced LVMI regression following treatment (low/normal ABP,−13±21 g/m2; remaining patients,−18±22 g/m2,P> 0.5).ConclusionsIn patients with hypertension and left ventricular hypertrophy, ambulatory BP is not superior to carefully standardized nurse-recorded seated BP in terms of associations with treatment-induced changes in LV mass.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BackgroundAmbulatory blood pressure assessments have been shown to be associated with subclinical and clinical endpoints even after controlling for the effects of clinic blood pressure.ObjectiveTo examine the incremental validity of ambulatory over clinic blood pressures using equivalent time periods, equivalent numbers of observations, and comparable measurement instruments across both settings.Design and MethodsIn this cross-sectional study of 216 healthy, community volunteers (ages 50–70 years), we compared three types of assessment in terms of their association with carotid artery atherosclerosis: manual clinic blood pressure (two readings, 10 min interval), automated clinic blood pressure (four readings, 2.5 h interval), and automated ambulatory blood pressure (four readings, 2.5 h interval) using the same type of automated device for the latter two conditions. These measurements were obtained during the morning hours on three separate occasions. Carotid intima–medial thickness and plaque were assessed, by ultrasound, as markers of atherosclerosis.ResultsGreater ambulatory systolic and diastolic blood pressure were associated with increased intima–medial thickness and an increased prevalence of plaque (odds ratios>3.0), even after statistical adjustment for clinic blood pressure assessments and demographic covariates.ConclusionsWe conclude that the independent utility of ambulatory over clinic blood pressure cannot be attributed to methodological issues that have traditionally confounded these comparisons. These findings highlight the potential importance of behavioral and lifestyle factors in contributing to the incremental value of ambulatory blood pressure.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BackgroundTwin and family studies have shown that genetic effects explain a relatively high amount of the phenotypic variation in blood pressure. However, many studies have not been able to replicate findings of association between specific polymorphisms and diastolic and systolic blood pressure.MethodsIn a structural equation-modelling framework the authors investigated longitudinal changes in repeated measures of blood pressures in a sample of 298 like-sexed twin pairs from the population-based Swedish Twin Registry. Also examined was the association between blood pressure and polymorphisms in the angiotensin-I converting enzyme and the angiotensin II receptor type 1 with the ‘Fulker’ test. Both linkage and association were tested simultaneously revealing whether the polymorphism is a Quantitative Trait Locus (QTL) or in linkage disequilibrium with the QTL.ResultsGenetic influences explained up to 46% of the phenotypic variance in diastolic and 63% of the phenotypic variance in systolic blood pressure. Genetic influences were stable over time and contributed up to 78% of the phenotypic correlation in both diastolic and systolic blood pressure. Non-shared environmental effects were characterised by time specific influences and little transmission from one time point to the next. There was no significant linkage and association between the polymorphisms and blood pressure.ConclusionsThere is a considerable genetic stability in both diastolic and systolic blood pressure for a 6-year period of time in adult life. Non-shared environmental influences have a small long-term effect. Although associations with the polymorphisms could not be replicated, results should be interpreted with caution due to power considerations.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

BackgroundIn a Caucasian population, the prevalence and incidence of hypertension, renal function and large artery stiffness were significantly correlated with polymorphisms in the genes encoding the angiotensin-converting enzyme (ACE I/D), aldosterone synthase (−C344T) and the cytoskeleton protein α-adducin (Gly460Trp).ObjectiveThis study investigated intima–media thickening, a precursor of atherosclerosis, in relation to these genetic polymorphisms.MethodsCarotid and femoral intima–media thickness were assessed with a wall-track system in 380 subjects enrolled in a population study. Subjects were genotyped for the presence of the ACE D, aldosterone synthase−344T and α-adducin 460Trp alleles. The statistical analysis allowed for confounders, interactions among genes, and the non-independence of the phenotypes within families.ResultsThe sample included 188 men (49.5%). Mean age was 39.8 years. Intima–media thickness of the carotid and femoral arteries averaged 575 and 719 μm, respectively. Intima–media thickness of the femoral–but not carotid–artery increased with the number of ACE D alleles. The effect of ACE genotype on femoral intima–media thickness was confined to carriers of the 460Trp allele and the−344T allele. Expressed as a percentage of the population mean, the mean differences between II and DD homozygotes averaged 13.4% (95% CI 5.6–21.2%) in all subjects, 21.2% (8.0–34.5%) in carriers of the 460Trp allele, 15.4% (4.1–26.8%) in carriers of the−344T allele, and 25.2% (10.7–39.7%) if the 460Trp and−344T alleles were both present.ConclusionThis study shows that a relationship exists between the intima–media thickness of the large muscular femoral artery and the ACE gene. This relationship is only apparent in the presence of either the α-adducin 460Trp or the aldosterone synthase −344T allele. These findings may have clinical implications for the assessment of genetic cardiovascular risk.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID

摘要:

ObjectiveConcentric left ventricular (LV) hypertrophy is an important cardiovascular risk factor. We investigated whether concentric LV hypertrophy is associated with activation of the vascular endothelium, as assessed by measurements of soluble cell adhesion molecules.DesignE-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular adhesion molecule-1 (VCAM-1) were measured in serum from hypertensive patients with LV hypertrophy (64 with concentric and 47 with eccentric hypertrophy) and from two matched control groups consisting of 38 hypertensive patients without LV hypertrophy and 38 normotensive subjects. Carotid artery intima–media thickness (IMT) was examined by ultrasonography and LV mass by echocardiography. Neurohormone activities of the renin–angiotensin–aldosterone system were also measured.ResultsE-selectin levels were higher in hypertensive than in normotensive subjects (56 ± 19 versus 49 ± 11 ng/ml,P= 0.031). Patients with concentric LV hypertrophy had higher levels of E-selectin (61 ± 21 versus 49 ± 15 ng/ml,P<0.001), ICAM-1 (273 ± 49 versus 254 ± 49 ng/ml,P= 0.043), VCAM-1 (591 ± 131 versus 544 ± 78 ng/ml,P= 0.038) and greater carotid artery IMT (0.99 ± 0.26 versus 0.83 ± 0.15 mm,P= 0.018) than eccentric LV hypertrophy patients. E-selectin and VCAM-1 correlated positively to LV relative wall thickness (P= 0.040 and 0.037, respectively), with a similar trend for ICAM-1 (P= 0.083). E-selectin correlated with serum aldosterone (P<0.001), and E-selectin and ICAM-1 with plasma angiotensin converting enzyme activity (P= 0.003 and 0.036, respectively).ConclusionIncreased levels of soluble cell adhesion molecules and an increased carotid artery IMT characterize concentric LV hypertrophy. This indicates perturbations at the vascular level, involving activation of the vascular endothelium in hypertensive patients with concentric LV hypertrophy.

ISSN:0263-6352    

出版商:OVID    

年代:2002

数据来源: OVID