Central adiposity and decreased heart rate variability in postmenopause: a cross-sectional study.

OBJECTIVE: To investigate the impact of waist circumference (WC) on heart rate variability in 87 apparently healthy, postmenopausal women. METHODS: In this cross-sectional study, time- and frequency-domain heart rate variability indices were determined at rest and during sympathetic stimulation with mental stress. Patients were stratified according to WC ≥ or < 88 cm. The mean (± standard deviation) age was 55 ± 5 years. The median time since menopause was 6 (range 1-22) years. Age and time since menopause were similar. RESULTS: The mean body mass index was 27.12 ± 4.49 kg/m². Metabolic syndrome was diagnosed in 26 (29.5%) participants. Thirty-eight participants (43.6%) had hypertension. Women with WC ≥ 88 cm had higher body mass index, glucose and insulin (both fasting and after a 75-g oral glucose tolerance test), HOMA, triglycerides, and free androgen index (p < 0.05). The metabolic syndrome was more frequent in women with WC ≥ 88 cm (24.13% vs. 5.74%; p < 0.01). At rest, women with WC ≥ 88 cm presented lower vagal modulation, expressed by a reduction in the mean of all normal RR intervals (mean RR) (p < 0.01) and root mean square of successive differences of adjacent RR intervals (rMSSD) (p < 0.05) than women with WC < 88 cm. Mental stress significantly increased sympathetic modulation in both groups, expressed by reduction in high frequency (HF), increase in low frequency (LF) and LF/F ratio, and reduction in mean RR and rMSSD. CONCLUSIONS: Less favorable metabolic profile and lower cardiac vagal modulation with preserved sympathetic responsiveness were found in participants with WC ≥ 88 cm, suggesting that central adiposity may be associated with decreased heart rate variability in apparently healthy, postmenopausal women.

Reliability of two methods for measurement of alveolar bone level in children.

OBJECTIVES: To determine the intra- and interexaminer reliability of two methods (calliper and computerized images) for measuring the alveolar bone level on bitewing radiographs of pre-school children and to determine the extent to which one method can measure more sites. METHODS: Standardized paediatric bitewings were analysed with either an image analysis program (ImageTool) or a digital calliper (Digimatic Caliper). With each method, radiographs were measured three times by three trained examiners. The differences in the number of sites measured with the two methods were assessed with McNemar's tests and kappa statistics. Reliability was assessed with paired t-tests, intraclass correlation coefficients (ICCs), Bland-Altman and survival-agreement plots. RESULTS: The kappa statistics and McNemar's test indicated that examiners measured 14% fewer sites using ImageTool. Paired t-tests also demonstrated a statistically significant bias (range 0.11-0.23 mm) indicating larger measurements for this method, although these observed differences were considered clinically unimportant for the detection of 2 mm of bone loss (which was considered the threshold for periodontal disease). Intra- and interexaminer reliability (ICC range: 0.87-0.97) was considered good for both methods. CONCLUSIONS: Reliable methods to assess alveolar bone loss in primary teeth are important for the diagnosis of incipient periodontal diseases. Both studied methods proved to be reliable. With the Digimatic Caliper, however, more sites were measured.

Acute water ingestion increases arterial blood pressure in hypertensive and normotensive subjects.

In patients with severe autonomic dysfunction, water ingestion elicits an acute pressor response. Hypertension may be associated with changes in cardiovascular autonomic modulation, but there is no information on the acute effects of water ingestion in patients with hypertension. In this study, we compared the effect of acute water ingestion on haemodynamic and autonomic responses of hypertensive and normotensive individuals. Eight patients with mild hypertension were compared to 10 normotensive individuals. After 30 min resting in the supine position all subjects ingested 500 ml of water. At baseline and after water ingestion, venous blood samples for plasma volume determination were collected, and electrocardiographic tracings, finger blood pressure, forearm blood flow and muscle sympathetic nerve activity (MSNA) were obtained. Water ingestion resulted in similar and minor reduction in plasma volume. Systolic and diastolic blood pressure increased in both hypertensive (mean+/-s.d.: 19/14+/-6/3 mm Hg) and normotensive subjects (17/14+/-6/3 mm Hg). There was an increase in forearm vascular resistance and in MSNA. Heart rate was reduced (hypertensive: 5+/-1 beats/min, normotensive: 5+/-6 beats/min) and the high-frequency component of heart rate and systolic blood pressure variability was increased. In hypertensive and normotensive individuals, acute water ingestion elicits a pressor response, an effect that is most likely determined by an increased vasoconstrictor sympathetic activity, and is counterbalanced by an increase in blood pressure and heart rate vagal modulation.

Absence of association between depression and hypertension: results of a prospectively designed population-based study.

The objective of this study was to examine the relation between hypertension and depression. In a cross-sectional study of the urban region of a State capital with more than 1.5 million inhabitants, 1174 men and women aged 18-80 years, selected at random from the population, were studied. Blood pressure, hypertension (blood pressure readings >or=140/90 mm Hg or use of blood pressure-lowering agents), risk factors for hypertension and depression according to the Diagnostic and Statistical Manual of Mental Disorders (fourth edition) were investigated in home interviews. The prevalence of major depression and hypertension were 12.4% (95% confidence interval (CI): 10.5-14.3) and 34.7% (95% CI: 32.2-37.4), respectively. Systolic and diastolic blood pressures of individuals with and without a lifetime episode of depression were not different after adjustment for age and gender. Lifetime episodic major depression was not associated with hypertension in bivariate analysis (risk ratios (RR): 0.96, 95% CI: 0.76-1.23) and after adjustment for confounding (RR: 1.15; 95% CI:0.75-1.76). Hypertension and depression were not associated in this free-living population of adults, suggesting that their concomitant occurrence in clinical practice may be ascribed to chance.

Acute haemodynamic effects of a hypertonic saline/dextran solution in stable patients with severe sepsis.

OBJECTIVE: To study the haemodynamic effects of a hypertonic saline/dextran solution compared with a normal saline solution in patients with severe sepsis. DESIGN: Prospective double blind and control-randomised study. SETTING: Adult intensive care unit in a university hospital. PATIENTS: Twenty-nine patients with sepsis with a pulmonary artery occlusion pressure (PAOP) lower than 12 mmHg. INTERVENTIONS: Patients were randomised to receive 250 ml of blinded solutions of either normal saline (SS group, n=16) or hypertonic saline (NaCl 7.5%)/dextran 70 8% (HSS group, n=13) solutions. MEASUREMENTS AND RESULTS: Haemodynamic, blood gas, and sodium data were collected at the following time points: baseline, 30 min, 60 min, 120 min, and 180 min. PAOP was higher in the HSS group at 30 min (10.7+/-3.2 mmHg vs 6.8+/-3.2 mmHg) and 60 min (10.3+/-3 mmHg vs 7.4+/-2.9 mmHg); P<0.05. The cardiac index increased in the HSS group and it was greater than the SS group at 30 min (6.5+/-4.7 l min(-1) m(-2) vs 3.8+/-3.4 l min(-1) m(-2)), 60 min (4.9+/-4.5 l min(-1) m(-2) vs 3.7+/-3.3 l min(-1) m(-2)), and 120 min (5.0+/-4.3 l min(-1) m(-2) vs 4.1+/-3.4 l min(-1) m(-2)); P<0.05. The stroke volume index followed a comparable course and it was higher at 30 min [53.6(39.2-62.8) ml m(-2) vs 35.6(31.2-49.2) ml m(-2)] and 60 min [46.8(39.7-56.6) ml m(-2) vs 33.9(32.2-47.7) ml m(-2)]; P<0.05. Systemic vascular resistance decreased in the HSS group and became significantly lower at 30 min (824+/-277 dyne s(-1) cm(-5) m(-2) vs 1139+/-245 dyne s(-1) cm(-5) m(-2)), 60 min (921+/-256 dyne s(-1) cm(-5) m(-2) vs 1246+/-308 dyne s(-1) cm(-5) m(-2)), and 120 min (925+/-226 dyne s(-1) cm(-5) m(-2) vs 1269+/-494 dyne s(-1) cm(-5) m(-2)). Sodium levels increased in the HSS group (P=0.056) and were higher than in the SS group at 30 min (145+/-3 mEq l(-1)vs 137+/-7 mEq l(-1)), 60 min (143+/-4 mEq l(-1) vs 136+/-7 mEq l(-1)), 120 (142+/-5 mEq l(-1)vs 136+/-7 mEq l(-1)), and 180 min (142+/-5 mEq l(-1) vs 136+/-8 mEq l(-1)). CONCLUSION: Hypertonic saline/dextran solution may improve cardiovascular performance in severe sepsis without significant side effects. The haemodynamic effect appears related mainly to a volume effect.

Contribution of nitric oxide to arterial pressure and heart rate variability in rats submitted to high-sodium intake.

The aim of this study was to determine the contribution of NO to arterial pressure and heart rate variability in normotensive rats subjected to high sodium intake. Arterial pressure, heart rate, and arterial pressure and heart rate variability, baroreflex sensitivity, and pressure responsiveness were measured in male Wistar rats treated for 6 weeks (control and high sodium [1%] intake groups), before and after acute NO synthesis blockade. After treatment, no changes were observed in arterial pressure or heart rate. Arterial pressure variability was increased after sodium intake; however, heart rate variability and baroreflex sensitivity were not modified in high-sodium rats. NO synthase blockade increased arterial pressure in both groups but was higher in the high-sodium group (from 110+/-5 to 162+/-1.5 mm Hg) compared with the control group (from 109+/-6.7 to 144+/-10 mm Hg). The increase in arterial pressure was accompanied by a decrease in heart rate (from 354+/-28 to 303+/-25 bpm in control rats and from 380+/-34 to 298+/-30 bpm in high-sodium rats). NO synthase blockade increased the tachycardic response to sodium nitroprusside in high-sodium rats. Arterial pressure variability, evaluated by a nonlinear method (3D return maps), showed a larger reduction in response to NO synthase inhibition in the high-sodium group (from 162+/-26 to 34.8+/-8.6 for general index of beat-to-beat blood pressure variability) than in the control group (from 58+/-9.6 to 36+/-4.7 for general index of beat-to-beat blood pressure variability). Heart rate variability, evaluated by the SD of the R-R intervals, was not changed in control rats but was increased by NO synthase inhibition in the high-sodium rats (from 9.5+/-0.2 to 21.9+/-1.7 milliseconds). These findings suggest an important role for increased NO production in adaptation to high-sodium intake. The increase in NO system sensitivity in high-sodium intake may contribute to changes in the autonomic nervous system regulating heart rate and, especially, arterial pressure variability.

Enhancement of heart rate variability by cholinergic stimulation with pyridostigmine in healthy subjects.

The purpose of this study was to determine the effect of the oral administration of pyridostigmine bromide on indices of heart rate variability (HRV) in healthy young volunteers. Seventeen healthy participants (11 men, 6 women; aged 27 +/- 8 y) submitted to a randomized, crossover, double-blind protocol, in which they received 30 mg pyridostigmine bromide (PYR) or placebo orally at 8-hour intervals for 24 hours, on two separate days. Venous blood samples were collected 2 and 24 hours after the first dose for determination of serum cholinesterase activity. Holter tapes were recorded during the 24-hour period and analyzed using a semiautomatic technique to evaluate time- and frequency-domain indices of HRV and to build three-dimensional return maps for later quantification. Symptoms were mild and occurred similarly during administration of PYR and placebo (p = 0.140). Serum cholinesterase activity was reduced by 15% at 2 hours (p = 0.013) and by 14% at 24 hours (p = 0.010) after the first dose of PYR, but not after administration of placebo. Pyridostigmine administration caused a significant increase in the mean 24-hour R-R interval (placebo: 814 +/- 20 msec; PYR: 844 +/- 18 msec; p = 0.003) and in time-domain indices of HRV, such as the standard deviation of all R-R intervals (SDNN; placebo: 151 +/- 9 msec; PYR: 164 +/- 9 msec; p = 0.017), and the percentage of pairs of adjacent R-R intervals differing by more than 50 msec (pNN50; placebo: 12.8 +/- 1.8%; PYR: 13.9 +/- 1.5%; p = 0.029). Pyridostigmine had no significant effect on frequency-domain indices of HRV, but resulted in significant increase in P2, a parasympathetic index derived from the three-dimensional return map (placebo: 93 +/- 13 msec; PYR: 98 +/- 13 ms; p = 0.029). In conclusion, low-dose pyridostigmine reduced mean heart rate and increased HRV during a 24-hour period in healthy young subjects.

Parasympathetic dysautonomia precedes left ventricular systolic dysfunction in Chagas disease.

BACKGROUND: Parasympathetic dysautonomia is an established feature of advanced Chagas cardiomyopathy. However, in the absence of cardiac involvement, the presence of vagal dysfunction remains controversial. In a cross-sectional study, we compared patients with Chagas disease without cardiac involvement and healthy individuals by three different methods to determine whether vagal dysfunction is present in the early phase of Chagas disease. METHODS: Sixty-one patients with Chagas disease without cardiac involvement and 38 controls were submitted to respiratory sinus arrhythmia test and 24-hour Holter monitoring. Vagal heart influences were assessed by the expiratory/inspiratory (E/I) ratio, time-domain indexes of heart rate variability (HRV), and by the quantification of a 3-dimensional return map. RESULTS: The two groups were comparable in terms of left ventricular ejection fraction and left ventricular end-diastolic dimension. Compared with the control group, patients with Chagas disease had significantly lower values of the E/I ratio (mean +/- SD: 1.38 +/- 0.02 and 1.25 +/- 0.02, P <.004) and short-term indexes of HRV (median [interquartile range]-rMSSD: 23 [18-27] and 17 [13-23], P =.00; pNN50: 11 [7-17] and 6 [2-12], P =.00). P(3), a beat-to-beat HRV index derived from the 3-dimensional return map, also was significantly reduced in the Chagas disease group (mean +/- SD: 118 +/- 5 vs 100 +/- 4, P =.00). None of these indexes of vagal heart control were significantly correlated with left ventricular function or to the presence of esophageal radiologic abnormalities. CONCLUSION: Parasympathetic dysautonomia is an independent and early phenomenon in Chagas disease and may precede left ventricular systolic dysfunction.

Three-dimensional return map: a new tool for quantification of heart rate variability.

BACKGROUND: Several methods are used to study heart rate variability, but they have limitations, which might be overcome by the use of a three-dimensional return map. OBJECTIVES: To evaluate the performance of three-dimensional return map-derived indices to detect (1) sympathetic and parasympathetic modulation to the sinus node and (2) autonomic dysfunction in diabetic patients. METHODS: Six healthy subjects underwent partial and total pharmacological autonomic blockade in a protocol that incorporated vagal and sympathetic predominance. Twenty-two patients with type 2 diabetes mellitus and 12 normal controls participated in the subsequent validation experiment. Three-dimensional return maps were constructed by plotting RRn intervals versus the difference between adjacent RR intervals [(RRn+1)-(RRn)] versus the number of counts, and four derived indices (P1, P2, P3, MN) were created for quantification. RESULTS: Both indices P1 and MN were significantly increased after sympathetic blockade with propranolol, while all indices except P1 were modified after parasympathetic blockade (P < 0.05). During the validation experiments, P1 and MN detected differences between normal controls, and diabetic patients with and without autonomic neuropathy. The overall accuracy of most three-dimensional indices to detect autonomic dysfunction, estimated by the area under the ROC curve, was significantly better than traditional time domain indices. Three-dimensional return map-derived indices also showed adequate reproducibility on two different recording days (intra-class correlation coefficients of 0.69 to 0.82; P < 0.001). CONCLUSIONS: Three-dimensional return map-derived indices are reproducible, quantify parasympathetic as well as sympathetic modulation to the sinus node, and are capable of detecting autonomic dysfunction in diabetic patients.

Familial predisposition to hypertension and the association between urinary sodium excretion and blood pressure in a population-based sample of young adults.

The reasons for the inconsistent association between salt consumption and blood pressure levels observed in within-society surveys are not known. A total of 157 normotensive subjects aged 18 to 35 years, selected at random in a cross-sectional population-based survey, answered a structured questionnaire. They were classified as strongly predisposed to hypertension when two or more first-degree relatives had a diagnosis of hypertension. Anthropometric parameters were obtained and sitting blood pressure was determined with aneroid sphygmomanometers. Sodium and potassium excretion was measured by flame spectrophotometry in an overnight urine sample. A positive correlation between blood pressure and urinary sodium excretion was detected only in the group of individuals strongly predisposed to hypertension, both for systolic blood pressure (r = 0.51, P<0.01) and diastolic blood pressure (r = 0.50, P<0.01). In a covariance analysis, after controlling for age, skin color and body mass index, individuals strongly predisposed to hypertension who excreted amounts of sodium above the median of the entire sample had higher systolic and diastolic blood pressure than subjects classified into the remaining conditions. The influence of familial predisposition to hypertension on the association between salt intake and blood pressure may be an additional explanation for the weak association between urinary sodium excretion and blood pressure observed in within-population studies, since it can influence the association between salt consumption and blood pressure in some but not all inhabitants.

Atrial automaticity and atrioventricular conduction in athletes: contribution of autonomic regulation.

Little is known about the sinoatrial automatism and atrioventricular conduction of trained individuals who present a normal resting electrocardiogram. We used transesophageal atrial stimulation, a minimally invasive technique, to evaluate aerobically trained athletes (n = 10) and sedentary individuals (n = 10) with normal resting electrocardiograms, to test the hypothesis that parasympathetic tone, as detected by heart rate variability, could be associated with changes in sinoatrial automatism and atrioventricular conduction. Corrected sinus node recovery time tended to be longer in athletes than in sedentary individuals, but this difference did not reach statistical significance. The Wenckebach point occurred at a lower rate in athletes than in the controls. Over a 24-h period of measurement, the mean RR interval was longer in the athletes than in the sedentary individuals. The mean square root of successive differences (rMSSD) tended to be higher in athletes than in controls, but this difference did not reach statistical significance. There was a moderate correlation (r = 0.48, P < 0.05) between the index of atrioventricular conduction, the rate at the Wenckebach point, and the logarithmically transformed rMSSD. Thus, as a corollary to its effects on the sinus node, where increased parasympathetic tone, decreased sympathetic tone, and non-autonomic components may contribute to sinus bradycardia, it is possible that athletic training may also induce intrinsic adaptations in the conduction system, which could contribute to the higher prevalence of atrioventricular conduction abnormalities observed in athletes.

Autonomic dysfunction and urinary albumin excretion rate are associated with an abnormal blood pressure pattern in normotensive normoalbuminuric type 1 diabetic patients.

OBJECTIVE: To analyze the role of autonomic function and other possible factors associated with a blunted fall in nocturnal blood pressure. RESEARCH DESIGN AND METHODS: A total of 39 normotensive normnoalbuminuric type 1 diabetic patients were studied. Glomerular filtration rate (51Cr-EDTA technique), extracellular volume (51Cr-EDTA distribution volume), and urinary albumin excretion rate (UAER) (by radioimmunoassay) were measured. The subjects' 24-h ambulatory blood pressure and a 24-h electrocardiogram were recorded simultaneously Heart rate variability was calculated in the time domain for 24 h, in the frequency domain at night, at rest in the supine position, and during tilt. Patients were classified according to diastolic blood pressure (dBP) night/day ratio as dipper patients (< or =0.9) and nondipper patients (>0.9). RESULTS: Nondipper patients presented a higher low-frequency (LF) component (a sympathetic index) and higher LF/high-frequency (HF) ratio during sleep than dipper patients (0.29 +/- 0.12 vs. 0.19 +/- 0.10 normalized units [n.u.], P = 0.008; and 0.98 +/- 0.53 vs. 0.55 +/- 0.45 n.u., P = 0.007, respectively). At rest, the LF component in nondipper patients (0.38 +/- 0.13 n.u.) was higher than in dipper patients (0.27 +/- 0.12 n.u., P = 0.04). After the tilt, nondipper patients did not show an increase in the LF component (P = 0.32), but in dipper patients, the increase was significant (P = 0.001). In both groups, tilting promoted a decrease in the HF component (a parasympathetic index). In a stepwise multiple linear regression analysis, the LF component during sleep and the UAER accounted for 24% of the variability in the dBP night/day ratio. CONCLUSIONS: The predominance of sympathetic activity and increased levels of UAER, although within the normal range, are associated with a blunted fall in nocturnal dBP in normoalbuminuric normotensive type 1 diabetic patients.

Familial predisposition to hypertension and the association between urinary sodium excretion and blood pressure in a population-based sample of young adults

The reasons for the inconsistent association between salt consumption and blood pressure levels observed in within-society surveys are not known. A total of 157 normotensive subjects aged 18 to 35 years, selected at random in a cross-sectional population-based survey, answered a structured questionnaire. They were classified as strongly predisposed to hypertension when two or more first-degree relatives had a diagnosis of hypertension. Anthropometric parameters were obtained and sitting blood pressure was determined with aneroid sphygmomanometers. Sodium and potassium excretion was measured by flame spectrophotometry in an overnight urine sample. A positive correlation between blood pressure and urinary sodium excretion was detected only in the group of individuals strongly predisposed to hypertension, both for systolic blood pressure (r = 0.51, P<0.01) and diastolic blood pressure (r = 0.50, P<0.01). In a covariance analysis, after controlling for age, skin color and body mass index, individuals strongly predisposed to hypertension who excreted amounts of sodium above the median of the entire sample had higher systolic and diastolic blood pressure than subjects classified into the remaining conditions. The influence of familial predisposition to hypertension on the association between salt intake and blood pressure may be an additional explanation for the weak association between urinary sodium excretion and blood pressure observed in within-population studies, since it can influence the association between salt consumption and blood pressure in some but not all inhabitants.

[Association of various measurements of obesity and the prevalence of hypertension]. / Associação entre diferentes indicadores de obesidade e prevalência de hipertensão arterial.

PURPOSE: To evaluate the association between body mass index (BMI), waist-hip ratio and waist circumference with the prevalence of hypertension in a representative sample of 1088 adults of Porto Alegre (RS), Brazil. METHODS: In this cross-sectional survey, subjects were considered as having hypertension if they had systolic blood pressure > or = 160 mmHg or diastolic > or = 90 mmHg, and were considered obese if they had BMI > or = 27 kg/m2, or had a waist-hip-ratio > or = 0.95 cm (men) or 0.80 (women) or had a waist circumference > or = 96 (men) or 92 (women). RESULTS: Obesity defined by the BMI was associated with hypertension in both genders (RR 1.9, CI 1.0-3.2 in men; RR 2.2, CI 1.3-3.8 in women). The other indices were significantly associated with hypertension just in women. CONCLUSION: BMI > or = 27.0 kg/m2 was strongly associated with increased odds to have hypertension. Similar magnitude of the association with the other indices indicate their utility to estimate the risk of hypertension.

Effect of partial arrhythmia suppression with amiodarone on heart rate variability of patients with congestive heart failure.

BACKGROUND: Some antiarrythmic agents that may increase mortality rates have been shown to reduce heart rate variability in patients with heart failure. Amiodarone is a potent antiarrhythmic agent that may reduce mortality rates in heart failure, but little is known about its effects on heart rate variability. METHODS AND RESULTS: The purpose of this study was to evaluate the effect of partial arrhythmia suppression by amiodarone on indexes of heart rate variability in patients with heart failure. Ten clinically stable patients in New York Heart Association class II-III received amiodarone during a 4-week period (600 mg every day for 14 days and 300 mg every day for 16 days), and 24-hour Holter recordings were performed before and after treatment. Heart rate variability indexes were calculated by a semiautomatic method that applies a 20% filter to the temporal series, excluding ectopy and compensatory pauses. After amiodarone administration, there was a significant reduction in pNN50 from 8% +/- 7% to 3% +/- 2% (p < 0.05) and there was a trend toward reduction in rMSSD (p = 0.06). Other time domain indexes did not change significantly. Spectral analysis demonstrated a significant reduction of low-frequency components (421 +/- 122 to 151 +/- 25 msec2; p < 0.05) and total power (1503 +/- 314 to 609 +/- 144 msec2, p < 0.05). Multivariate analysis showed that the observed reduction in pNN50 was strongly associated with the number and the reduction of ventricular premature contractions before and after amiodarone administration (r2 = 0.94; p < 0.01). CONCLUSIONS: These findings indicate that despite the use of software corrections for arrhythmia, short-term time domain indexes of heart rate variability may be affected by partial suppression of ectopy.

Alcohol intake and blood pressure: the importance of time elapsed since last drink.

BACKGROUND: A positive association of chronic exposure to alcoholic beverages with blood pressure and the prevalence of hypertension has been described in epidemiological surveys, but the influence of time elapsed since last ingestion in this setting was not demonstrated. DESIGN: A cross-sectional, population-based survey. METHODS: In total 1089 adults from Porto Alegre, randomly selected from a population-based, multi-stage probability sample, were interviewed at home. The average daily alcohol intake of each subject was calculated taking into account the concentration of ethanol in the beverages (distilled or fermented beverages), and the time elapsed between the last ingestion of ethanol and the moment of blood pressure determination. Standardized sitting blood pressure and anthropometric parameters were collected. The magnitude and shape of the associations were analyzed considering blood pressure as a continuous variable and the prevalence of arbitrarily defined hypertension. Simple and multiple linear regression models, including models to identify nonlinear associations, with quadratic and cubic terms of the amount of alcohol consumed, were employed. Blood pressure means were compared by analysis of variance and analysis of covariance. The association between hypertension and exposure to ethanol was analyzed through logistic regression models, controlling for various potential confounders. RESULTS: Positive nonlinear associations of the amount of alcohol consumed with blood pressure and the prevalence of hypertension (> or = 160/95 mmHg) were found, independent of age, years of education, smoking, and use of oral contraceptive and antihypertensive drugs. The consumption of 30 g/day ethanol was associated with increases of 1.5 and 2.3 mmHg in diastolic and systolic blood pressures, respectively, for men, and 2.1 and 3.2 mmHg, respectively, for women. The prevalence of hypertension was higher among those ingesting more than 30 g/day (odds ratio = 2.9, P < 0.01). The time elapsed between the last ingestion and blood pressure measurement was independently associated with the prevalence of hypertension. Men with last consumption of alcohol 13-23 h prior to measurement had odds of being hypertensive 2.6 (confidence interval 1.3-5.0) greater than did subjects who had consumed alcoholic beverages 24 h and more before the blood pressure determination. For men, systolic and diastolic blood pressures were lower during the first 3 h after ingestion and increased afterward. Frequency of consumption and type of beverage consumed were not independently associated with level of blood pressure. CONCLUSION: A time-dependent association between alcohol consumption and effects on blood pressure, demonstrated in experimental studies, was found for free-living individuals selected at random.

Associaçäo entre diferentes indicadores de obesidade e prevalência de hipertensäo arterial / The association between different measurements of obesity and the prevalence of hypertension

OBJETIVO - Determinar a associaçäo entre índice de massa corporal (IMC), índice cintura-quadril e cintura com a prevalência de hipertensäo arterial (HAS) em amostra representativa de 1088 adultos de Porto Alegre, Brasil. MÉTODOS - Foram considerados hipertensos indivíduos com pressäo sistólica (PAS) 'maior ou igual' 160mmHg ou diastólica (PAD) 'maior ou igual' 95mmHg e definidos como obesos aqueles com IMC 'maior ou igual' 27kg/m², ou com razäo cintura/quadril 'maior ou igual'0,95 (homens) e 'maior ou igual'0,80 (mulheres) ou com cintura 'maior ou igual 96cm (homens) e 92 'maior ou igual'(mulheres). RESULTAODS - A obesidade aferida pelo IMC associou-se com prevalência de HAS em ambos sexos (RR 1,9, IC 1,0 - 3,2 masculino; RR 2,2, IC 1,3 - 3,8 feminino). Os outros índices associaram-se, significativamente, apenas nas mulheres. CONCLUSÄO - IMC 'maior ou igual' 27,0kg/m² associou-se mais, consistentemente com o risco de HAS. A magnitude similar das associaçöes dos demais indicadores demostram sua utilidade na avaliaçäo do risco para a hipertensäo.

Sympathetic nervous system representation in time and frequency domain indices of heart rate variability.

This study evaluated the contributions of sympathetic and parasympathetic modulation to heart rate variability during situations in which vagal and sympathetic tone predominated. In a placebo-controlled, randomized, double blind blockade study, six young healthy male individuals received propranolol (0.2 mg x kg(-1)), atropine (0.04 mg x kg(-1)), propranolol plus atropine, or placebo infusions over 4 days. Time-domain indices were calculated during 40 min of rest and 20 min of exercise at 70% of maximal exercise intensity. Spectrum analysis, using fast Fourier transformation, was also performed at rest and during the exercise. The time-domain indices standard deviation of R-R intervals, mean of the standard deviations of all R-R intervals for all 5-min segments, percentage of number of pairs of adjacent R-R intervals differing by more than 50 ms, and square root of the mean of the sum of squares of differences between adjacent R-R intervals were reduced after atropine and propranolol plus atropine. Propranolol alone caused no appreciable change in any of the time-domain indices. At rest, all spectrum components were similar after placebo and propranolol infusions, but following parasympathetic and double autonomic blockade there was a reduction in all components of the spectrum analysis, except for the low:high ratio. During exercise, partial and double blockade did not change significantly any of the spectrum components. Thus, time and frequency-domain indices of heart rate variability were able to detect vagal activity, but could not detect sympathetic activity. During exercise, spectrum analysis is not capable of evaluating autonomic modulation of heart rate.