In the European Project on Genes in Hypertension (EPOGH) standardized epidemiological methods were used to determine complex phenotypes consisting of blood pressure (BP) in combination with other ...traits. In this report, we present the quality control of one of the BP phenotypes.
In seven European countries eight different research groups recruited random samples of nuclear families. Trained observers measured the BP five times consecutively with the participants in the seated position at each of two separate home visits, 1 to 3 weeks apart, according to the guidelines of the British Hypertension Society. Quality assurance and quality control of this BP phenotype were implemented according to detailed instructions defined in the protocol of the EPOGH study.
On 31 August 2001, BP measurements of 2476 subjects were available for analysis. Fewer BP readings than the five planned per visit occurred in one of the eight centres, but only in 0.4% of the home visits. Across centres the relative frequency of identical consecutive readings for systolic or diastolic blood pressure varied from 0 to 6%. The occurrence of odd readings ranged from 0 to 0.1%. Of the 49,488 systolic and diastolic BP readings, 24.0% ended on a zero (expected 20%). In most EPOGH centres there was a progressive decline in the BP from the first to the second home visit. Overall, these decreases averaged 2.36 mmHg 95% confidence interval (CI): 1.98-2.74, P < 0.001 for systolic BP and 1.74 mmHg (95% CI: 1.46-2.02, P < 0.001) for diastolic BP.
Quality assurance and control should be planned at the design stage of a project involving BP measurement and implemented from its very beginnings until the end. The procedures of quality assurance set up in the EPOGH study for the BP measurements resulted in a well-defined BP phenotype, which was consistent across centres.
Systolic hypertension increases the risk of dementia in elderly people. The vascular dementia project, set up in the framework of the double-blind placebo-controlled Systolic Hypertension in Europe ...(Syst-Eur) trial, investigated whether antihypertensive drug treatment could reduce the incidence of dementia.
Eligible patients had no dementia, were at least 60 years old, and had a blood pressure when seated of 160-219 mm hg systolic and below 95 mm hg diastolic. Active treatment consisted of nitrendipine (10-40 mg/day) with the possible addition of enalapril (5–20 mg/day), hydrochlorothiazide (12.5–25 mg/day), or both drugs, titrated or combined to reduce the systolic blood pressure by at least 20 mm hg to reach a value below 150 mm hg. Cognitive function was assessed by the mini mental state examination (MMSE). If the MMSE score was 23 or less, diagnostic tests for dementia were done (DSM-III-R criteria). The cause of dementia was established by the modified ischaemic score with brain imaging or the Hachinski score.
Median follow-up by intention to treat was 2·0 years. Compared with placebo (n=1180), active treatment (n=1238) reduced the incidence of dementia by 50% from 7·7 to 3·8 cases per 1000 patient-years (21
vs 11 patients, p=0·05). The median MMSE score at randomisation was 29 in both treatment groups. At the last available assessment, systolic and diastolic blood pressure were, respectively, 8·3 mm hg and 3·8 mm hg lower (plt;0·001) in the active-treatment group, but on average the MMSE scores did not change in either group. In the control patients, however, the MMSE decreased (p=0·04) with decreasing diastolic blood pressure, whereas in the active-treatment group MMSE scores improved slightly (p=0·01) with greater reduction in diastolic blood pressure (p=0·002 for between-group difference).
In elderly people with isolated systolic hypertension, antihypertensive treatment was associated with a lower incidence of dementia. If 1000 hypertensive patients were treated with antihypertensive drugs for 5 years 19 cases of dementia might be prevented.
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DOBA, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SIK, UILJ, UKNU, UL, UM, UPCLJ, UPUK, VSZLJ
Sympathetic tone increases with stimulation of the renin-angiotensin system and is under the influence of salt intake. In the European Project On Genes in Hypertension (EPOGH), we investigated ...whether polymorphisms in the genes encoding aldosterone synthase (CYP11B2 C–344T) and the type-1 angiotensin II receptor (AT1R A1166C) affect the autonomic modulation of heart rate at varying levels of salt intake. We measured the low frequency (LF) and high frequency (HF) components of heart rate variability and their ratio (LF:HF) in the supine and standing positions in 1797 participants (401 families and 320 unrelated subjects) randomly selected from 6 European populations, whose average urinary sodium excretion ranged from 163 to 245 mmol/d. In multivariate analyses with sodium excretion analyzed as a continuous variable, we explored the phenotype–genotype associations using generalized estimating equations and quantitative transmission disequilibrium tests. Across populations, there was no heterogeneity in the phenotype–genotype relations. The genotypic effects differed according to sodium excretion. In subjects with sodium excretion <190 mmol/d (median), supine heart rate, LF, and LF:HF increased and HF decreased with the number of CYP11B2–344T alleles, and the orthostatic changes in LF, HF, and LF:HF were blunted in carriers of the AT1R 1166C allele. In subjects with sodium excretion >190 mmol/d, these associations with the CYP11B2 and AT1R polymorphisms were nonsignificant or in the opposite direction, respectively. Thus, CYP11B2 C–344T and AT1R A1166C polymorphisms affect the autonomic modulation of heart rate, but these genetic effects depend on sodium excretion.
OBJECTIVEIn a population-based sample of nuclear families recruited in the framework of the European Project on Genes in Hypertension (EPOGH), we investigated the association between heart rate (HR) ...and its variability (HRV), and gender, age, posture, breathing frequency, body mass index, systolic blood pressure, family history of hypertension and various lifestyle factors, such as smoking, alcohol and coffee consumption and physical activity.
METHODSRR interval and respiration were registered in the supine and standing positions (15 min each) in 1208 subjects in Bucharest (Romania, n = 267), Cracow (Poland, n = 323), Mirano (Italy, n = 323) and Novosibirsk (Russian Federation, n = 295). After exclusion of 199 participants on antihypertensive treatment and/or patients with diabetes mellitus (n = 40) or myocardial infarction (n = 4), 993 subjects were eligible for analysis. We evaluated 858 participants with high-quality recordings. Using fast Fourier transform, we decomposed HRV into low-frequency (LF0.04–0.15 Hz) and high-frequency (HF0.15–0.40 Hz) components, which were expressed in normalized units.
RESULTSMean values were 35.3 years for age, 24.3 kg/m for body mass index (BMI) and 121.0/77.2 mmHg for blood pressure. The group included 462 (53.8%) women. Across four centres, HR and HRV were similarly and independently associated with gender, age and postural position (P < 0.001). In the supine position, HR was higher in women than men (67.2 versus 63.7 bpm). Men had higher normalized LF power than women (48.8 versus 41.5), but lower HF power (40.6 versus 47.4). The normalized HF power decreased with age (r = –0.43), whereas LF power increased (r = 0.32). On standing, HR increased (83.3 versus 65.6 bpm), normalized HF power declined (19.2 versus 44.3) and LF power increased (67.4 versus 44.9). The independent effects of respiration frequency, systolic blood pressure, family history of hypertension, body mass index and lifestyle factors on HRV differed between populations, and explained no more than 8% of the total variance.
CONCLUSIONSAcross four European populations, gender, age and posture were consistent and independent correlates of HR and HRV. Lifestyle seems to have small but varying influences on HR and/or HRV, probably depending on the environmental and cultural background of the population under study.
BACKGROUND After the double-blind, placebo-controlled Systolic Hypertension in Europe (Syst-Eur) trial ended in February 1997, randomized patients were offered active study medication for a further ...period of observation. OBJECTIVE To refine the estimates of the long-term effects of antihypertensive therapy on the incidence of dementia. METHODS Eligible patients had no dementia and were at least 60 years old. Their systolic blood pressure at entry was 160 to 219 mm Hg, with diastolic blood pressure below 95 mm Hg. Antihypertensive therapy was started immediately after randomization in the active treatment group, but only after termination of the double-blind trial in the control patients. Treatment consisted of nitrendipine (10-40 mg/d), with the possible addition of enalapril maleate (5-20 mg/d), hydrochlorothiazide (12.5-25 mg/d), or both add-on drugs. RESULTS Median follow-up increased from 2.0 years in the double-blind trial to 3.9 years overall. The incidence of dementia doubled from 32 to 64 cases, 41 of whom had Alzheimer disease. Throughout follow-up, systolic/diastolic blood pressure was 7.0/3.2 mm Hg higher in the 1417 control patients than in the 1485 subjects randomized to active treatment. At the last examination, the blood pressure difference was still 4.2/2.9 mm Hg; 48.1%, 26.4%, and 11.4% of the control patients were taking nitrendipine, enalapril, and/or hydrochlorothiazide, whereas in the active treatment group these proportions were 70.2%, 35.4%, and 18.4%, respectively. Compared with the controls, long-term antihypertensive therapy reduced the risk of dementia by 55%, from 7.4 to 3.3 cases per 1000 patient-years (43 vs 21 cases, P<.001). After adjustment for sex, age, education, and entry blood pressure, the relative hazard rate associated with the use of nitrendipine was 0.38 (95% confidence interval, 0.23-0.64; P<.001). Treatment of 1000 patients for 5 years can prevent 20 cases of dementia (95% confidence interval, 7-33). CONCLUSION The extended follow-up of Syst-Eur patients reinforces the evidence that blood pressure–lowering therapy initiated with a long-acting dihydropyridine protects against dementia in older patients with systolic hypertension.Arch Intern Med. 2002;162:2046-2052-->
Hypertension is a chronic age-related disorder, affecting nearly 20% of all adult Europeans. This disease entails debilitating cardiovascular complications and is the leading cause for drug ...prescriptions in Europeans older than 50 years. Intensive research over the past two decades has so far failed to identify common genetic polymorphisms with a major impact on blood pressure or associated cardiovascular phenotypes, suggesting that multiple genes each with a minor impact, along with gene-gene and gene-environment interactions, play a role. The European Project on Genes in Hypertension (EPOGH) is a large-scale, family-based study in which participants from seven different populations were phenotyped and genotyped according to standardized procedures. This review article summarizes the initial 5-year findings and puts these observations into perspective against other published studies. The EPOGH demonstrated that phenotype-genotype relations strongly depend on host factors such as gender and lifestyle, in particular salt intake as reflected by the 24-h urinary excretion of sodium. The EPOGH therefore highlights the concept that phenotype-genotype relations can only be studied within a defined ecogenetic context.
In the double-blind Systolic Hypertension in Europe (Syst-Eur) Trial, active treatment was initiated with nitrendipine (10 to 40 mg/d) with the possible addition of enalapril (5 to 20 mg/d) and/or ...hydrochlorothiazide (12.5 to 25 mg/d) titrated or combined to reduce sitting systolic blood pressure by at least 20 mm Hg to <150 mm Hg. In the control group, matching placebos were used similarly. In view of persistent concerns about the use of calcium channel blockers as first-line antihypertensive drugs, this report explored to what extent nitrendipine, administered alone, prevented cardiovascular complications. Age at randomization averaged 70.2 years and systolic/diastolic blood pressure 173.8/85.5 mm Hg. Of 2398 actively treated patients, 1327 took only nitrendipine (average dose, 23.4 mg/d), and 1042 progressed to other treatments including nitrendipine (n=757; 35.7 mg/d), enalapril (n=783; 13.4 mg/d), and/or hydrochlorothiazide (n=294; 21.0 mg/d). Compared with the whole placebo group (n=2297), patients receiving monotherapy with nitrendipine had 25% (P=0.05) fewer cardiovascular end points, and those progressing to other active treatments showed decreases (P<or=to0.01) in total mortality (40%), stroke (59%), and all cardiovascular end points (39%). Among the control patients, 863 used only the first-line placebo. Compared with this subgroup, patients receiving monotherapy with nitrendipine showed a nearly 50% (P<or=to0.004) reduction of all types of end points, including total and cardiovascular mortality. The full relative benefit from nitrendipine was seen as early as 6 months after randomization. To ascertain that the benefit conferred by the dihydropyridine was not due to selection bias, the 1327 patients remaining on monotherapy with nitrendipine were matched by gender, age, previous cardiovascular complications, and systolic blood pressure at entry with an equal number of placebo patients. In this analysis, nitrendipine reduced (P<or=to0.05) cardiovascular mortality by 41%, all cardiovascular end points by 33%, and fatal and nonfatal cardiac end points by 33%. Despite the limitations inherent in post hoc analyses, the present findings suggest that the calcium channel blocker nitrendipine, given as a single antihypertensive medication, prevents cardiovascular complications in older patients with isolated systolic hypertension. (Hypertension. 1998;32:410-416.)
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