Evaluation of Adherence to Nutritional Intervention Through Trajectory Analysis

Classical pre-post intervention studies are often analyzed using traditional statistics. Nevertheless, the nutritional interventions have small effects on the metabolism and traditional statistics are not enough to detect these subtle nutrient effects. Generally, this kind of studies assumes that the participants are adhered to the assigned dietary intervention and directly analyzes its effects over the target parameters. Thus, the evaluation of adherence is generally omitted. Although, sometimes, participants do not effectively adhere to the assigned dietary guidelines. For this reason, the trajectory map is proposed as a visual tool where dietary patterns of individuals can be followed during the intervention and can also be related with nutritional prescriptions. The trajectory analysis is also proposed allowing both analysis: 1) adherence to the intervention and 2) intervention effects. The analysis is made by projecting the differences of the target parameters over the resulting trajectories between states of different time-stamps which might be considered either individually or by groups. The proposal has been applied over a real nutritional study showing that some individuals adhere better than others and some individuals of the control group modify their habits during the intervention. In addition, the intervention effects are different depending on the type of individuals, even some subgroups have opposite response to the same intervention.

Effects of total dietary polyphenols on plasma nitric oxide and blood pressure in a high cardiovascular risk cohort. The PREDIMED randomized trial

BACKGROUND AND AIM

Hypertension is one of the main cardiovascular risk factors in the elderly. The aims of this work were to evaluate if a one-year intervention with two Mediterranean diets (Med-diet) could decrease blood pressure (BP) due to a high polyphenol consumption, and if the decrease in BP was mediated by plasma nitric oxide (NO) production.

METHODS AND RESULTS

An intervention substudy of 200 participants at high cardiovascular risk was carried out within the PREDIMED trial. They were randomly assigned to a low-fat control diet or to two Med-diets, one supplemented with extra virgin olive oil (Med-EVOO) and the other with nuts (Med-nuts). Anthropometrics and clinical parameters were measured at baseline and after one year of intervention, as well as BP, plasma NO and total polyphenol excretion (TPE) in urine samples. Systolic and diastolic BP decreased significantly after a one-year dietary intervention with Med-EVOO and Med-nuts. These changes were associated with a significant increase in TPE and plasma NO. Additionally, a significant positive correlation was observed between changes in urinary TPE, a biomarker of TP intake, and in plasma NO (Beta = 4.84; 95% CI: 0.57-9.10).

CONCLUSIONS

TPE in spot urine sample was positively correlated with plasma NO in Med-diets supplemented with either EVOO or nuts. The statistically significant increases in plasma NO were associated with a reduction in systolic and diastolic BP levels, adding to the growing evidence that polyphenols might protect the cardiovascular system by improving the endothelial function and enhancing endothelial synthesis of NO.

Mediterranean diet and non enzymatic antioxidant capacity in the PREDIMED study: evidence for a mechanism of antioxidant tuning

BACKGROUND AND AIMS

The intake of antioxidant-rich foods may increase the blood levels of non enzymatic antioxidant capacity (NEAC). NEAC takes into account all antioxidants from food and synergistic effects between them. We examined the effect of a 1-year intervention with Mediterranean diet on plasma NEAC and assessed whether it was related to baseline NEAC levels.

METHODS AND RESULTS

Five hundred sixty-four participants at high cardiovascular risk were randomly selected from the PREDIMED (Prevención con DIeta MEDiterránea) Study, a large 3-arm randomized clinical trial. Blood NEAC levels were measured at baseline and after 1-year of dietary intervention with 1) a Mediterranean diet supplemented with virgin olive oil (MED + VOO); 2) a Mediterranean diet supplemented with nuts (MED + nuts), or 3) a control low-fat diet. Plasma NEAC was analyzed using FRAP (ferric reducing antioxidant potential) and TRAP (total radical-trapping antioxidant parameter) assays. Plasma FRAP levels increased after 1-year of intervention with MED + VOO [72.0 μmol/L (95% CI, 34.2-109.9)] and MED + nuts [48.9 μmol/L (24.3-73.5)], but not after the control low-fat diet [13.9 μmol/L (-11.9 to 39.8)]. Participants in the lowest quartile of plasma FRAP at baseline significantly increased their levels after any intervention, while those in the highest quartile decreased. Similar results occurred with TRAP levels.

CONCLUSIONS

This study shows that a 1-year of MED diet intervention increases plasma TAC level in subjects at high risk for cardiovascular disease. Moreover, the effectiveness of dietary supplementation with antioxidants may be related to baseline levels of plasma NEAC.

Dietary intake and major food sources of polyphenols in a Spanish population at high cardiovascular risk: the PREDIMED study

BACKGROUND AND AIMS

Epidemiological data have shown an inverse association between the consumption of polyphenol-rich foods and the risk of cardiovascular disease or overall mortality. A comprehensive estimation of individual polyphenol intake in nutritional cohorts is needed to gain a better understanding of this association. The aim of this study was to estimate the quantitative intake of polyphenols and the major dietary sources in the PREDIMED (PREvención con DIeta MEDiterránea) cohort using individual food consumption records.

METHODS AND RESULTS

The PREDIMED study is a large, parallel-group, multicentre, randomised, controlled 5-year feeding trial aimed at assessing the effects of the Mediterranean diet on the primary prevention of cardiovascular disease. A total of 7200 participants, aged 55-80 years, completed a validated 1-year food frequency questionnaire (FFQ) at baseline. Polyphenol consumption was calculated by matching food consumption data from the FFQ with the recently developed Phenol-Explorer database on polyphenol content in foods. The mean total polyphenol intake was 820 ± 323 mg day⁻¹ (443 ± 218 mg day⁻¹ of flavonoids and 304 ± 156 mg day⁻¹ of phenolic acids). Hydroxycinnamic acids were the phenolic group with the highest consumption and 5-caffeoylquinic acid was the most abundantly ingested individual polyphenol. The consumption of olives and olive oil was a differentiating factor in the phenolic profile of this Spanish population compared with other countries.

CONCLUSION

In Mediterranean countries, such as Spain, the main dietary source of polyphenols is coffee and fruits, but the most important differentiating factor with respect to other countries is the consumption of polyphenols from olives and olive oil.

Gazpacho consumption is associated with lower blood pressure and reduced hypertension in a high cardiovascular risk cohort. Cross-sectional study of the PREDIMED trial

BACKGROUND AND AIM

Hypertension is a major public health problem and a leading cause of death and disability in both developed and developing countries, affecting one-quarter of the world's adult population. Our aim was to evaluate whether the consumption of gazpacho, a Mediterranean vegetable-based cold soup rich in phytochemicals, is associated with lower blood pressure (BP) and/or reduced prevalence of hypertension in individuals at high cardiovascular risk.

METHODS AND RESULTS

We selected 3995 individuals (58% women, mean age 67 y) at high cardiovascular risk (81% hypertensive) recruited into the PREDIMED study. BP, weight, and dietary and physical activity data were collected. In multivariate linear regression analyses, after adjustment, moderate and high gazpacho consumption categories were associated with reduced mean systolic BP of -1.9 mm Hg [95% confidence interval (CI): -3.4; -0.6] and -2.6 mm Hg (CI: -4.2; -1.0), respectively, and reduced diastolic BP of -1.5 mm Hg (CI: -2.3; -0.6) and -1.9 mm Hg (CI: -2.8; -1.1). By multiple-adjusted logistic regression analysis, gazpacho consumption was associated with a lower prevalence of hypertension, with OR = 0.85 (CI: 0.73; 0.99) for each 250 g/week increase and OR = 0.73 (CI: 0.55; 0.98) for high gazpacho consumption groups compared to the no-consumption group.

CONCLUSIONS

Gazpacho consumption was inversely associated with systolic and diastolic BP and prevalence of hypertension in a cross-sectional Mediterranean population at high cardiovascular risk. The association between gazpacho intake and reduction of BP is probably due to synergy among several bioactive compounds present in the vegetable ingredients used to make the recipe.

Bone quantitative ultrasound measurements in relation to the metabolic syndrome and type 2 diabetes mellitus in a cohort of elderly subjects at high risk of cardiovascular disease from the PREDIMED study

OBJECTIVE

The aim of this study is to determine whether metabolic syndrome, its individual components, or the presence of type 2 diabetes mellitus are associated with a better bone status estimated by quantitative ultrasound at the calcaneus.

DESIGN

Cross-sectional study.

SETTING

Outpatient clinics.

PARTICIPANTS

251 elderly subjects at high cardiovascular risk from the PREDIMED study were included.

MEASUREMENTS

MetS was defined according to the ATPIII diagnosis criteria. Calcaneus quantitative ultrasound (QUS) assessment was performed using the Sahara system.

RESULTS

Subjects with MetS showed significantly lower 24-hour urinary deoxypyridinoline/creatinine (u-DPD/creatinine) levels and higher broadband ultrasound attenuation, and a tendency to higher bone mineral density (BMD) and quantitative ultrasound index (QUI) than their counterparts. Individuals with type 2 diabetes mellitus (T2DM) showed a significantly higher bone broadband ultrasound attenuation (BUA) and QUI than their non-diabetic counterparts, despite they shown a higher prevalence of osteoporotic fractures. Multiple linear regression analyses showed that quantitative ultrasound parameters were positively associated with the metabolic syndrome and T2DM. Of the bone biochemical markers, only u-DPD/creatinine was related to MetS, abdominal obesity, hypertriglyceridemia component of the MetS, and the number of features that define the MetS.

CONCLUSION

This is the first study showing a positive association between MetS or T2DM with better bone status and lower bone resorption markers measured by quantitative ultrasound. Our results suggest that metabolic abnormalities have a positive effect on healthy bone in elderly subjects at high risk of cardiovascular disease.

Total polyphenol excretion and blood pressure in subjects at high cardiovascular risk

BACKGROUND AND AIMS

Dietary factors are critical for the prevention and treatment of hypertension, but data on the effects of specific nutrients on blood pressure (BP) are scarce. The aim of this study was to assess the relationship between total polyphenol excretion (TPE) in urine, as an objective measurement of total polyphenol intake and BP in an elderly population at high cardiovascular risk.

METHODS AND RESULTS

Cross-sectional substudy of 589 high-risk participants entering in the PREDIMED trial. BP was measured and TPE was determined in urine by Folin-Ciocalteu assay. A significant positive association was observed between TPE in urine and daily intake of fruit and vegetables (F&V), coffee or wine after adjusting for potential confounders. The intake of 100 g of F&V (Beta=0.150;P<0.001) had a greater contribution to TPE than 100 mL of coffee (Beta=0.141;P=0.001), and the latter two foods contributed more than the consumption of 100 mL of wine (Beta=0.120;P=0.019). An inverse association was observed between urinary TPE and the prevalence of hypertension. Participants in the highest quartile of urinary TPE had a reduced prevalence of hypertension compared to those in the lowest quartile (Odds Ratio=0.64; 95% confidence interval 0.45 to 0.92; P=0.015). Systolic and diastolic BP were inversely associated with urinary TPE after adjustment for potential confounders (P=0.024 and P=0.003, respectively).

CONCLUSIONS

Polyphenol intake, assessed via TPE in urine, was negatively associated with BP levels and prevalence of hypertension in an elderly Mediterranean population at high cardiovascular risk. Participants with the highest intake of polyphenol-rich foods showed the lowest BP measurements.

Olive oil and health: summary of the II international conference on olive oil and health consensus report, Jaén and Córdoba (Spain) 2008

Olive oil (OO) is the most representative food of the traditional Mediterranean Diet (MedDiet). Increasing evidence suggests that monounsaturated fatty acids (MUFA) as a nutrient, OO as a food, and the MedDiet as a food pattern are associated with a decreased risk of cardiovascular disease, obesity, metabolic syndrome, type 2 diabetes and hypertension. A MedDiet rich in OO and OO per se has been shown to improve cardiovascular risk factors, such as lipid profiles, blood pressure, postprandial hyperlipidemia, endothelial dysfunction, oxidative stress, and antithrombotic profiles. Some of these beneficial effects can be attributed to the OO minor components. Therefore, the definition of the MedDiet should include OO. Phenolic compounds in OO have shown antioxidant and anti-inflammatory properties, prevent lipoperoxidation, induce favorable changes of lipid profile, improve endothelial function, and disclose antithrombotic properties. Observational studies from Mediterranean cohorts have suggested that dietary MUFA may be protective against age-related cognitive decline and Alzheimer's disease. Recent studies consistently support the concept that the OO-rich MedDiet is compatible with healthier aging and increased longevity. In countries where the population adheres to the MedDiet, such as Spain, Greece and Italy, and OO is the principal source of fat, rates of cancer incidence are lower than in northern European countries. Experimental and human cellular studies have provided new evidence on the potential protective effect of OO on cancer. Furthermore, results of case-control and cohort studies suggest that MUFA intake including OO is associated with a reduction in cancer risk (mainly breast, colorectal and prostate cancers).

Characterization of human gene expression changes after olive oil ingestion: an exploratory approach

Olive oil consumption is protective against risk factors for cardiovascular and cancer diseases. A nutrigenomic approach was performed to assess whether changes in gene expression could occur in human peripheral blood mononuclear cells after oli ve oil ingestion at postprandial state. Six healthy male volunteers ingested, at fasting state, 50 ml of olive oil. Prior to intervention a 1-week washout period with a controlled diet and sunflower oil as the only source of fat was followed. During the 3 days before and on the intervention day, a very low-phenolic compound diet was followed. At baseline (0 h) and at post-ingestion (6 h), total RNA was isolated and gene expression (29,082 genes) was evaluated by microarray. From microarray data, nutrient-gene interactions were observed in genes related to metabolism, cellular processes, cancer, and atherosclerosis (e.g. USP48 by 2.16; OGT by 1.68-fold change) and associated processes such as inflammation (e.g. AKAP13 by 2.30; IL-10 by 1.66-fold change) and DNA damage (e.g. DCLRE1C by 1.47; POLK by 1.44- fold change). When results obtained by microarray were verified by qRT-PCR in nine genes, full concordance was achieved only in the case of up-regulated genes. Changes were observed at a real-life dose of olive oil, as it is daily consumed in some Mediterranean areas. Our results support the hypothesis that postprandial protective changes related to olive oil consumption could be mediated through gene expression changes.

Effect of olive oil consumption on serum resistin concentrations in healthy men

Resistin has been linked to atherosclerosis and inflammatory processes in humans. Some polyphenols have been shown to downregulate resistin expression in adipocytes. The effects of olive oil phenolics on resistin are not known; therefore, we investigated the impact of olive oil consumption on serum resistin as a function of the olive oils' phenolic content. In a randomized, controlled, cross-over study 38 healthy German men aged 38+/-2 years replaced their usual consumption of raw fat during 3 periods of 3 weeks each by 25 ml of virgin, common and refined olive oil varying in phenolic content. Serum resistin, blood lipids and urine biomarkers of subjects' compliance were analysed at baseline and at the end of each intervention period. The integration of olive oil in the subjects' habitual diet led to a decrease in total cholesterol (p=0.025) and triglycerides (p=0.013) independent of the content of phenolic compounds in the oil. Serum resistin concentrations were not affected by the olive oils' phenolic content. After low phenolic olive oil consumption, a decrease in serum resistin level was observed compared to medium and high phenolic olive oil (-0.4+/-0.1 ng/ml; p=0.040). Our results suggest that olive oil consumption has only marginal beneficial effects on serum resistin levels.

Anti-inflammatory effect of virgin olive oil in stable coronary disease patients: a randomized, crossover, controlled trial

OBJECTIVES

To assess the effect of two similar olive oils, but with differences in their phenolic compounds (powerful antioxidant compounds), on inflammatory markers in stable coronary heart disease patients.

DESIGN

Placebo-controlled, crossover, randomized trial.

SETTING

Cardiology Department of Hospital del Mar and Institut Municipal d'Investigació Mèdica (Barcelona).

SUBJECTS

Twenty-eight stable coronary heart disease patients.

INTERVENTIONS

A raw daily dose of 50 ml of virgin and refined olive oil (ROO) was sequentially administered over two periods of 3-weeks, preceded by 2-week washout periods in which ROO was used.

RESULTS

Interleukin-6 (P<0.002) and C-reactive protein (P=0.024) decreased after virgin olive oil intervention. No changes were observed in soluble intercellular and vascular adhesion molecules, glucose and lipid profile.

CONCLUSIONS

Consumption of virgin olive oil, could provide beneficial effects in stable coronary heart disease patients as an additional intervention to the pharmacological treatment.

Amount and Intensity of Physical Activity, Fitness, and Serum Lipids in Pre-Menopausal Women

The aim of the study was to determine the association between the amount and the intensity of physical activity (PA) and lipid profile and fitness in pre-menopausal women. A cross-sectional study was conducted, sampling was stratified according to two age groups and two levels of PA, as assessed by the Minnesota Leisure Time PA Questionnaire. Serum lipid profile and sex hormones were measured. The study included 403 women. Total energy expenditure on PA was directly associated with HDL-cholesterol and inversely with atherogenic index. When intensity was analyzed, only moderate PA was associated with a desirable lipid profile. A decrease of 1.59 mg/dL (standard error [SE] = 0.77) and 0.07 units (SE = 0.02) in LDL-cholesterol and atherogenic index, respectively, and an increase of 1.02 mg/dL (SE = 0.34) in HDL-cholesterol were observed per each 100 MET . min/day spent in moderate PA. After adjusting for body fat mass, the association between moderate PA and LDL-cholesterol was no longer statistically significant (regression coefficient = - 1.21; SE = 0.81) whereas the association between moderate PA and atherogenic index (regression coefficient = - 0.05; SE = 0.02) and HDL-cholesterol (regression coefficient = 0.98; SE = 0.35) remained statistically significant. Only vigorous PA was associated with VO2max. VO2max increased 2.35 mL/kg (SE = 0.39) per each 100 MET . min/day spent in vigorous PA. Only moderate PA is associated with a lower LDL-cholesterol and atherogenic index, and higher HDL-cholesterol. The association between PA and LDL is dependent on body fat mass, but the association between PA and HDL is independent of it. Only vigorous intensity PA is associated with fitness.

High monetary costs of dietary patterns associated with lower body mass index: a population-based study

INTRODUCTION

Food choice is strongly influenced through economic constraints. The monetary costs for foods, especially those foods associated with a lower risk of obesity, have considerably increased during the last years. The purpose of this study was to determine the cost differences between low and high adherence to two dietary patterns which have been inversely associated with body mass index (BMI) and obesity.

METHODS

The subjects were Spanish men (n=1547) and women (n=1615) aged 25-74 years who were examined in 1999-2000, in a population-based cross-sectional survey in the northeast of Spain (Girona). Dietary intake was assessed using a food frequency questionnaire. Two dietary quality indices, namely the Mediterranean Diet Score (MDS) and the Healthy Eating Index (HEI), were created. Average food prices were calculated. Anthropometric variables were measured.

RESULTS

Adjusted linear regression analysis revealed that an increase in 1 Euro (1.25$) of monetary diet costs per day was associated with a change of 0.46 units (P<0.001) and 2.03 units (P<0.001) in the MDS and HEI, respectively. The magnitude of the association was similar for both scores after standardization. Subjects who closely adhered to the MDS and HEI paid daily 1.2 Euro (1.50$) (P<0.001) and 1.4 Euro (1.75$) (P<0.001) more for food consumption, respectively, than those who weakly adhered to these dietary patterns. Multiple linear regression analysis adjusted for several confounders showed an inverse association of the MDS (P=0.011) and the HEI (P<0.001) with BMI. The risk of obesity (BMI> or =30) significantly decreased across quartile distribution of MDS (P=0.004) and HEI (P=0.001).

CONCLUSION

Data showed that a high adherence to the MDS and HEI, both inversely associated with BMI and obesity, led to higher monetary costs as compared to a low adherence. This might be of importance for public health policies in an effort to develop strategies to promote healthy diets preventing weight gain.

Antioxidant effect of virgin olive oil in patients with stable coronary heart disease: a randomized, crossover, controlled, clinical trial

The Mediterranean diet, in which olive oil is the main source of fat, has been associated with a reduced incidence of coronary heart disease (CHD) and low blood pressure levels. Virgin olive oil (VOO), besides containing monounsaturated fat, is rich in phenolic compounds (PC) with antioxidant properties. The aim of this study was to examine the antioxidant and anti-hypertensive effect of two similar olive oils, but with differences in their PC (refined: 14.7 mg/kg versus virgin: 161.0 mg/kg), in 40 males with stable CHD. The study was a placebo controlled, crossover, randomized trial. A raw daily dose of 50 mL of VOO and refined olive oil (ROO) were sequentially administered over two periods of 3 weeks, preceded by 2-week washout periods in which ROO was used. Lower plasma oxidized LDL (p < 0.001) and lipid peroxide levels (p = 0.003), together with higher activities of glutathione peroxidase (p = 0.033), were observed after VOO intervention. Systolic blood pressure decreased after intake of VOO (p = 0.001) in hypertensive patients. No changes were observed in diastolic blood pressure, glucose, lipids, and antibodies against oxidized LDL. Consumption of VOO, rich in PC, could provide beneficial effects in CHD patients as an additional and complementary intervention to the pharmacological treatment.

Bioavailability of phenolic compounds from olive oil and oxidative/antioxidant status at postprandial state in healthy humans

Olive oil phenolic compounds are generally believed to have beneficial antioxidant effects, but little is known about characteristics of their postprandial bioavailability in natural olive oil at real-life doses. The aim of the present study was to determine the concentrations of olive oil phenolic compounds in urine collected over 24 h (24-h urine) after a bolus ingestion of 25 ml of olive oil with different phenolic content, and to demonstrate the effect of this real-life olive oil dose on postprandial levels of blood lipids and oxidative stress biomarkers, as well as to examine the beneficial effects of olive oil phenols. Oral fat loads of 25 ml olive oil with high, moderate, and low phenolic content were administered to 12 healthy male volunteers in a randomized, controlled, crossover trial. Tyrosol and hydroxytyrosol were absorbed in a dose-dependent manner according to the phenolic content of the olive oil administered. The administered dose of 25 ml, which is close to that used daily in Mediterranean countries, did not induce significant postprandial lipemia nor did it promote an increase of in vivo oxidation markers. With regard to plasma antioxidant enzymes, glutathione peroxidase activity decreased postprandially after low phenolic content olive oil ingestion; however this was not observed after intake of moderate and high phenolic content olive oils. The phenolic content of the olive oils administered may account for the protection of the endogenous antioxidant defenses at postprandial state after ingestion of moderate and high phenolic content olive oils.

Response of oxidative stress biomarkers to a 16-week aerobic physical activity program, and to acute physical activity, in healthy young men and women

Physical activity (PA) is associated with a reduced risk of coronary heart disease, and may favorably modify the antioxidant-prooxidant balance. This study assessed the effects of aerobic PA training on antioxidant enzyme activity, oxidized LDL concentration, and LDL resistance to oxidation, as well as the effect of acute PA on antioxidant enzyme activity before and after the training period. Seventeen sedentary healthy young men and women were recruited for 16 weeks of training. The activity of superoxide dismutase in erythrocytes (E-SOD), glutathione peroxidase in whole blood (GSH-Px), and glutathione reductase in plasma (P-GR), and the oxidized LDL concentration and LDL composition, diameter, and resistance to oxidation were determined before and after training. Shortly before and after this training period they also performed a bout of aerobic PA for 30 min. The antioxidant enzyme activity was also determined at 0 min, 30 min, 60 min, 120 min, and 24 h after both bouts of PA. Training induces an increase in GSH-Px (27.7%), P-GR (17.6%), and LDL resistance to oxidation, and a decrease in oxidized LDL (-15.9%). After the bout of PA, an increase in E-SOD and GSH-Px was observed at 0 min, with a posterior decrease in enzyme activity until 30-60 min, and a tendency to recover the basal values at 120 min and 24 h. Training did not modify this global response pattern. Regular PA increases endogenous antioxidant activity and LDL resistance to oxidation, and decreases oxidized LDL concentration; 30 min of aerobic PA decreases P-GR and B-GSH-Px activity in the first 30-60 min with a posterior recovery.

Tyrosol and hydroxytyrosol are absorbed from moderate and sustained doses of virgin olive oil in humans

OBJECTIVE

To investigate the absorption of tyrosol and hydroxytyrosol from moderate and sustained doses of virgin olive oil consumption. The study also aimed to investigate whether these phenolic compounds could be used as biomarkers of virgin olive oil intake.

DESIGN AND INTERVENTIONS

Ingestion of a single dose of virgin olive oil (50 ml). Thereafter, for a week, participants followed their usual diet which included 25 ml/day of the same virgin olive oil as the source of raw fat.

SETTING

Unitat de Recerca en Farmacologia. Institut Municipal d'Investigació Mèdica (IMIM).

SUBJECTS

Seven healthy volunteers.

RESULTS

An increase in 24 h urine of tyrosol and hydroxytyrosol, after both a single-dose ingestion (50 ml) and short-term consumption (one week, 25 ml/day) of virgin olive oil (P<0.05) was observed. Urinary recoveries for tyrosol were similar after a single dose and after sustained doses of virgin olive oil. Mean recovery values for hydroxytyrosol after sustained doses were 1.5-fold those obtained after a single 50 ml dose.

CONCLUSIONS

Tyrosol and hydroxytyrosol are absorbed from realistic doses of virgin olive oil. With regard to the dose-effect relationship, 24 h urinary tyrosol seems to be a better biomarker of sustained and moderate doses of virgin olive oil consumption than hydroxytyrosol.

Bioavailability of tyrosol, an antioxidant phenolic compound present in wine and olive oil, in humans

Tyrosol is a phenolic compound present in two of the traditional components of the Mediterranean diet: wine and virgin olive oil. The presence of tyrosol has been described in red and white wines. Tyrosol is also present in vermouth and beer. Tyrosol has been shown to be able to exert antioxidant activity in in vitro studies. Oxidation of low-density lipoprotein (LDL) appears to occur predominantly in arterial intima in microdomains sequestered from antioxidants of plasma. The antioxidant content of the LDL particle is critical for its protection. Thus, phenolics, which are able to bind LDL, could be effective in preventing lipid peroxidation and atherosclerotic processes. The ability of tyrosol to bind human LDL has been reported. We have demonstrated the bioavailability of tyrosol in humans from virgin olive oil in its natural form. Urinary tyrosol increased, reaching a peak at 0-4 h after virgin olive oil administration. Men and women showed a different pattern of urinary excretion of tyrosol. Moreover, tyrosol is absorbed in a dose-dependent manner after sustained and moderate doses of virgin olive oil. In summary, our results suggest that tyrosol from wine or virgin olive oil could exert beneficial effects on human health in vivo if its biological properties are confirmed in in vivo studies.

Postprandial effects of wine consumption on lipids and oxidative stress biomarkers

Postprandial lipemia has been recognized as a risk factor for atherosclerosis development. Consuming meals with suitable sources of antioxidants such as red wine reduces postprandial oxidative stress. However, information about the postprandial effects of wine ingestion outside meals on lipids and on in vivo low-density lipoprotein (LDL) oxidation in humans is scarce. The aim of this study was to investigate postprandial changes in lipids and in vivo LDL oxidation after moderate (250 ml) red wine ingestion, before and after sustained wine consumption of 250 ml/day for 4 days. After 4 days of sustained wine consumption a decrease in the LDL/high-density lipoprotein cholesterol ratio was observed after wine ingestion (p = 0.026). On day 4, a decrease in oxidized LDL levels and an increase in the antioxidant enzyme glutathione peroxidase activity (p = 0.025) were observed after wine ingestion. Our results show that consumption of red wine at moderate doses outside meals does not promote oxidative stress. Daily consumption of moderate doses of red wine can improve postprandial lipid profile and oxidative status when wine is ingested outside meals.

Variables associated with fibrinogen in a population-based study: interaction between smoking and age on fibrinogen concentration

The aim of the study was to assess the association between fibrinogen and other cardiovascular risk factors. A cross-sectional population-based study in Gerona (Spain) was designed, 1544 subjects (747 men, 797 women) participated. Anthropometric measurements, blood pressure and blood samples were obtained. Fibrinogen was measured by a coagulometric method. Smoking habits, alcohol consumption and physical activity practice were recorded by questionnaires. Fibrinogen was directly related to age, body mass index (BMI) and female gender and inversely to alcohol and moderate-heavy physical activity practice. Fibrinogen was also higher in men and young women who smoked. In the multivariate analysis, age (regression coefficient (RC): 1.33; standard error (SE): 0.13; unit = 1 year), female gender (RC: 12.24; SE: 3.56) and BMI (RC: 1.83; SE: 0.39; unit = 1 kg/m2) were directly associated with fibrinogen, whereas alcohol (RC: -0.04; SE: 0.01; unit = 1 g/d) was inversely associated. A statistically significant interaction between smoking and age was observed. Age was the strongest variable associated with fibrinogen and modifies the association between smoking and fibrinogen; the magnitude of this association increases with age.

Scientific aspects that justify the benefits of the Mediterranean diet: mild-to-moderate versus heavy drinking

The Mediterranean diet is now recognized as being both limited in toxicity and abundant in nutrient and non-nutrient protective factors. A large body of basic, clinical and epidemiological studies have been developed in recent years to provide evidence of the benefits of the Mediterranean diet or its components on health. Evidence-based medicine ranks randomized controlled clinical trials as providing the highest level of evidence and expert opinions the lowest. On the basis of these criteria, the current state of knowledge about Mediterranean diet in primary and secondary prevention of disease and mortality and morbidity as functions of the amount of alcoholic beverage consumption, is reviewed. Efficacy versus effectiveness, the role of basic and animal research, and bioavailability studies providing evidence is also discussed.

Use of a three-day estimated food record, a 72-hour recall and a food-frequency questionnaire for dietary assessment in a Mediterranean Spanish population

AIM

To assess the validity and the short-term reproducibility of a semi-quantitative, self-administrated food frequency questionnaire and a structured 72-hour recall in a Mediterranean Spanish population.

METHODS

44 free-living volunteers participated in the study. Macronutrient, vitamin and mineral intake, recorded on the food frequency questionnaire and the structured 72-h recall were compared with intakes derived from a three-day food record (reference method). Validity of the dietary assessment methods was further assessed by comparing urinary nitrogen, plasma vitamin C, plasma beta-carotene and whole blood glutathione peroxidase activity levels with the corresponding nutrient intakes from the questionnaires. The food frequency questionnaire and the 72-h recall were administered twice to assess the short term reproducibility.

RESULTS

Pearson's correlation coefficients between urinary nitrogen, plasma vitamin C, plasma beta-carotene and whole blood glutathione peroxidase activity levels and the reported nitrogen, vitamin C, beta-carotene and selenium intakes were 0.26, 0.53, 0.17, 0.26 for the food frequency questionnaire; 0.41, 0.09, 0.34, 0.42 for the structured 72-h recall and 0.50, 0.54, 0.44, 0.38 for the three-day food record, respectively. The short term reproducibility of analysed nutrient intake showed average intra-class correlation coefficients of 0.91 and 0.69 for the food frequency questionnaire and the structured 72-h recall irrespectively.

CONCLUSION

The food frequency questionnaire and the structured 72-h recall provide valid estimates of nutrient intake and could be used for dietary assessments.

[Coronary disease protective factors: antioxidant effect of olive oil]

Alongside the French paradox, the REGICOR Study (Girona, Spain) has shown another paradox in the Mediterranean area: a high prevalence of cardiovascular risk factors with low incidence of myocardial infarction in the population of Girona, Spain. The antioxidant effects associated with olive oil consumption could explain part of this 'Mediterranean Paradox'. Virgin olive oils processed by two centrifugation phases and with low fruit ripeness have the highest levels of antioxidant content. The total content of phenolic compounds (PC) from virgin olive oil could delay LDL oxidation. The content and nature of olive oil PC have a high influence in the antioxidant capacity of an olive oil. PC from diet could bind human LDL in non-supplemented volunteers. PC from virgin olive oil could bind LDL and tyrosol is bioavailable in humans from ingestion of virgin olive oil in its natural form.

Virgin olive oil phenolic compounds: binding to human low density lipoprotein (LDL) and effect on LDL oxidation

Oxidation of low density lipoproteins (LDL) appears to occur predominantly in arterial intima in microdomains sequestered from antioxidants of plasma. Therefore phenolic compounds which are able to bind LDL are good drug candidates for the effective prevention of lipid peroxidation and atherosclerotic processes. Plasma from healthy volunteers on nonsupplemented diets was incubated with virgin olive oil phenolic extracts (0-200 mg/l, caffeic acid equivalents). Phenolic compounds in LDL were measured by high-performance liquid chromatography-diode array detection (HPLC-DAD). Copper-mediated LDL oxidation was performed, and conjugated dienes formation was monitored. After plasma preincubation with olive oil phenolic compounds (OOPC), an increased OOPC-concentration dependent was observed in the total phenolic content of LDL (p < 0.001, ANOVA) as well as in the lag time before conjugated diene formation (p < 0.001, ANOVA). Rutin and four phenolics with flavonoid-like spectra were found to be bound to the LDL control. These phenolics, together with tyrosol which was not present in the LDL control, significantly increased in LDL (p < 0.05) after plasma incubation with OOPC. These results show the ability of tyrosol to bind LDL in vitro and the capacity of virgin olive oil phenolics to protect other phenolic compounds previously bound to LDL. These results provide further evidence that phenolic compounds bound to LDL are likely to protect LDL from oxidation.

Capillary gas chromatography-mass spectrometry quantitative determination of hydroxytyrosol and tyrosol in human urine after olive oil intake

Recent in vitro studies have demonstrated antioxidant properties of some virgin olive oil phenolic compounds. One of the prerequisites to extrapolate these data to an in vivo situation is the knowledge of their bioavailability in humans. In the present work we describe an analytical method which enables us to perform hydroxytyrosol and tyrosol quantitative determinations in human urine. This method was successfully used in bioavailability studies of both phenolic compounds after acute olive oil administration. Virgin olive oil was administered to healthy volunteers after a low phenolic diet. The dose administered of both phenolic compounds was estimated in reference to free forms of hydroxytyrosol and tyrosol present in virgin olive oil extracts before and after being submitted to hydrolytic conditions. These conditions mimic those occurring during digestion. Urine samples were collected before and after acute olive oil intake and analyzed by capillary gas chromatography-mass spectrometry. Hydroxytyrosol and tyrosol urinary recovery increased in response to olive oil administration, obtaining maximal values in the first 4 h. Our results further indicate that hydroxytyrosol and tyrosol are mainly excreted in conjugated form, since only 5.9 +/- 1.4% (hydroxytyrosol) and 13.8 +/- 5.4% (tyrosol) of the total amounts excreted in urine were in free form.

Validation of the Minnesota Leisure Time Physical Activity Questionnaire In Spanish Women. Investigators of the MARATDON Group

PURPOSE

Regular physical activity (PA) is associated with lower risk for several chronic diseases. It is important to validate PA measurement instruments in different populations. The objective was to validate the Minnesota leisure time PA questionnaire among Spanish women.

METHODS

A cross-sectional study with quota sampling was designed. Two PA groups (active, expending less than 301 MET-min x d(-1) in PA, and very active, expending more than 300 MET-min x d(-1)) and two age groups (18-40 and 41-60 yr) were defined. The Minnesota questionnaire was administered to obtain total energy expenditure in leisure time PA (EEPAtotal) and classified according to the intensity of the different types of PA (EEPAheavy, EEPAmoderate, and EEPAlight). The 250 women recruited performed an exercise test to assess fitness.

RESULTS

Spearman correlation coefficients among EEPAtotal, EEPAheavy, EEPAmoderate, EEPAlight, and fitness were 0.39, 0.51, 0.13, and 0.02, respectively. Multiple linear regression model adjusted by the different EEPAs and age accounted for 46% of fitness variability. Besides age, only EEPAmoderate and EEPAheavy were associated with fitness.

CONCLUSION

The Spanish version of the Minnesota questionnaire is a valid instrument for measuring leisure time PA performed in the last year in Spanish women aged 18-60 yr. Moderate and heavy physical activity are adequately assessed whereas light physical activity practice assessment may be questionable.

[Olive oil and inhibition of low density lipoprotein oxidation. Role of phenolic compounds]

BACKGROUND

To investigate the protective effect of several olive oils with different phenolic composition on low density lipoprotein susceptibility to oxidation.

PATIENTS AND METHODS

Refined olive oil (phenolic content: 0 mg/l caffeic acid equivalents [CAE]), common olive oil (0.1 and 0.3 mg/l CAE), and virgin olive oil diluted with refined olive oil (0.1 y 0.3 mg/l CAE), were added to isolated low density lipoprotein. Conjugated dienes formation was monitored after copper-mediated low density lipoprotein oxidation.

RESULTS

An increase in the lag time of conjugated dienes formation after copper-mediated low density lipoprotein oxidation was observed linked to olive oil phenolic content (p < 0.0001, ANOVA). Multiple regression analysis showed that phenolics were the most significant antioxidants with 0.1 mg/l--increase in phenolic concentration, adjusted for alpha-tocopherol and beta-carotene, was 72 minutes (95% confidence interval [CI] 64 to 80 min) for common olive oil, and 111 min (CI 95%: 100-123 min) for virgin olive oil. In common olive oil alpha-tocopherol levels were significatively associated with the increase in the lag time (p = 0.003), reaching in virgin olive oil a borderline significant (p = 0.084).

CONCLUSIONS

Olive oil containing phenolics showed more antioxidant effect on low density lipoprotein oxidation than refined olive in relation to its phenolic content. The nature of the phenolic content influences the antioxidant capacity of an olive oil.

Decreased endogenous antioxidant enzymatic status in essential hypertension

Several lines of evidence suggest that patients with essential hypertension have impaired endothelial nitric oxide activity and increased superoxide anion production. However, the mechanisms underlying these abnormalities remain unknown. We measured enzymatic superoxide dismutase (SOD) and glutathione peroxidase (GPX) activities in erythrocytes and whole blood, respectively, in 30 newly-diagnosed, normolipidaemic untreated mild hypertensive patients and in 164 age-matched healthy controls. SOD and GPX activities in hypertensive patients (806 +/- 225 U/Hb.g and 5491 +/- 2073 U/L, respectively) were significantly lower than in the control group (931 +/- 202 U/Hb.g and 6669 +/- 1560 U/L, respectively) (P < 0.005). No significant association was found between these antioxidant enzyme activities and blood pressure in normotensive controls. In the hypertensives, only log-transformed SOD activity showed a significant negative correlation with systolic and diastolic blood pressure (r = 0.37, P < 0.05; r = 0.64, P < 0.0001, respectively). The low endogenous antioxidant enzyme activities observed may in turn result in decreased superoxide anion removal leading to nitric oxide inactivation. Journal of Human Hypertension (2000) 14, 343-345

Protective effect of olive oil and its phenolic compounds against low density lipoprotein oxidation

The protective effect of phenolic compounds from an olive oil extract, and of olive oils with (extra-virgin) and without (refined) phenolic components, on low density lipoprotein (LDL) oxidation was investigated. When added to isolated LDL, phenolics [0.025-0.3 mg/L caffeic acid equivalents (CAE)] increased the lag time of conjugated diene formation after copper-mediated LDL oxidation in a concentration-dependent manner. Concentrations of phenolics greater than 20 mg/L inhibited formation of thiobarbituric-acid reactive substances after AAPH-initiated LDL oxidation. LDL isolated from plasma after preincubation with phenolics (25-160 mg/L CAE) showed a concentration-dependent increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation. Refined olive oil (0 mg/L CAE) and extra-virgin olive oil (0.1 and 0.3 mg/L CAE) added to isolated LDL caused an increase in the lag time of conjugated diene formation after copper-mediated LDL oxidation that was related to olive oil phenolic content. Multiple regression analysis showed that phenolics were significantly associated with the increase in lag time after adjustment for effects of other antioxidants; alpha-tocopherol also achieved a statistically significant effect. These results indicate that olive oil phenolic compounds protect LDL against peroxyl radical-dependent and metal-induced oxidation in vitro and could associate with LDL after their incubation with plasma. Both types of olive oil protect LDL from oxidation. Olive oil containing phenolics, however, shows more antioxidant effect on LDL oxidation than refined olive oil.

Relationship of lipoprotein(a) levels to physical activity and family history of coronary heart disease

OBJECTIVES

This study evaluated the association of physical activity with serum lipoprotein(a) [La(a)] levels in individuals according to whether they had a family history of coronary heart disease (CHD).

METHODS

Lp(a) levels in 332 healthy Spanish men aged 20 to 60 years were measured. Physical activity and family history of CHD were assessed.

RESULTS

For men with a family history of CHD, the odds ratio for Lp(a) levels above the median value was 0.13 (95% confidence interval = 0.03, 0.50) in very active men (energy expended in physical activity > 300 kcal/day) compared with active men (energy expended in physical activity < 300 kcal/day).

CONCLUSIONS

Regular daily physical activity in individuals with a family history of CHD could be useful for controlling Lp(a) levels.

Differential expression of double-band apolipoprotein(a) phenotypes in healthy Spanish subjects detected by SDS-agarose immunoblotting

A sodium dodecyl sulphate-agarose apolipoprotein(a) [apo(a)] phenotyping method was set up to attain accurate scanning densitometry of proteins. Serum samples from 99 healthy Spanish men were analysed and twenty-five different apo(a) isoforms (12 to 37 kringle 4 repeats) were detected. Double-band phenotypes accounted for 39.4% (n = 39) and three different patterns of protein expression were identified: pattern A (20.5% of double-band phenotyped samples) predominantly expressed the highest molecular weight isoform; pattern B (53.9%) mainly the lowest molecular weight isoform, and pattern AB (25.6%), expressed both isoforms equally. A significant linear association between expression pattern and lipoprotein(a) [Lp(a)] concentration > or = 0.30 g/l was observed. Single-band phenotyped samples (n = 60) were stratified according to apo(a) kringle 4 repeat categories and showed that 90% of isoforms < 20 K4 repeats had high Lp(a) concentrations (> or = 0.30 g/l), whereas isoforms with 20 to 24 or more than 24 kringle 4 repeats had Lp(a) concentrations > or = 0.30 g/l in 47% and 14%, respectively. A logistic regression model was fitted to test the association between apo(a) size, expression pattern and Lp(a) concentration. In this model, apo(a) isoform < 25 kringle 4 repeats was significantly associated with serum Lp(a) concentration > or = 0.30 g/l in both single and double-band phenotyped samples (odds ratio = 8.9, p < 0.001). In the latter, a differential expression pattern with respect to smaller size isoforms (pattern AB vs A) was significantly associated with Lp(a) concentration > or = 0.30 g/l (odds ratio = 17.97, P = 0.045). Heterogeneity in protein apo(a) size expressed according to kringle 4 repeat number could be categorized in heterozygous phenotypes as three patterns. When small-sized isoform was expressed (pattern B) or both isoforms were equally expressed (pattern AB), the probability of having Lp(a) > or = 0.30 g/l is higher.

Captopril test and renal duplex scanning for the primary screening of renovascular disease

To evaluate the utility of renal duplex scanning and the captopril test in the detection and functional assessment of renovascular disease, by comparing their results with those of angiography and captopril isotopic renography (CIR). Sixty hypertensive patients with aortoiliac disease and 16 with clinically suspected renovascular hypertension (RVH) were included. All the patients underwent renal duplex scanning prior to angiography. In addition, isotopic renograms and a determination of peripheral plasma renin activity (PRA) at baseline and 60 min after oral intake of 50 mg of captopril were both performed. A postcaptopril PRA > 5.7 ng/mL/h was considered as diagnostic of a positive captopril test. On the basis of the results of the angiography and isotopic renograms, all the patients were classified into three groups: group I (n = 33), essential hypertension (EHT); group II (n = 20), hypertension and angiographic RAS > 60% but negative CIR; and group III (n = 24), RAS > 60% and positive CIR. This last condition was considered as highly suspicious for RVH. Renal duplex scanning showed greater accuracy than captopril PRA or CIR for detecting RAS > 60% (groups II and III) with 87.3% versus 52.4% and 45.3% sensitivity (S), and 91.5% versus 84.4% and 92.8% specificity (Sp), respectively. The captopril test correctly identified 44 of 51 EHT patients (groups I and II) and 20 of 23 highly suspected of RVH (group III) with 87% S, 86.5% Sp, 74.1% PPV, and 93.6% NPV. Accuracy was further increased when a combined approach (renal duplex scanning and captopril test) was followed (82.6% S, 93.7% Sp, 86.4 PPV, and 91.8 NPV). In our study, renal duplex scanning was a useful screening method for detecting anatomical RAS. A combination of both renal duplex scanning and captopril test may be an appropriate approach to the primary screening for RVH, thereby permitting the selection of those patients indicated for angiography.

Differential effects of 2'-deoxyguanosine on peripheral blood mononuclear cell proliferation in healthy donors and Hashimoto's thyroiditis patients

The aim of this study was to determine possible differences in peripheral blood mononuclear cells (PBMC) proliferation of healthy donors and Hashimoto's thyroiditis patients and whether a statistical approach to cell proliferation analysis might be used to discern the differences. The effect of a wide range of 2'-deoxyguanosine (dGuo) concentrations (0-1250 microM) on the mitogen-induced proliferation of PBMC was studied in healthy donors and Hashimoto's thyroiditis patients. Activity levels of purine nucleoside phosphorylase (PNP) and adenosine deaminase (ADA) in PBMC were also measured. For the first time in a study of these models of dGuo toxicity in vitro, the analysis of polynomial trends of orders from 1 to 7 was applied to evaluate cell proliferation. A dose-dependent inhibition of mitogen-induced PBMC proliferation was observed in both groups. Data for linear trend established that PBMC from Hashimoto's thyroiditis patients were more sensitive to dGuo toxicity than PBMC from healthy donors. A positive quadratic trend at low dGuo doses was found in the cell proliferation of Hashimoto's thyroiditis patients. A decrease in PNP activity (P < 0.025) and an increase in ADA activity (P < 0.005) was observed in PBMC of Hashimoto's thyroiditis group. The differences in PBMC proliferation subjected to dGuo toxicity between the two groups could be related with the distinct pattern of purine salvage enzymes observed.

Amount and intensity of physical activity, physical fitness, and serum lipids in men. The MARATHOM Investigators

Physical activity improves one's lipid profile and increases physical fitness. The present study was aimed at determining the association of amount and intensity of leisure time physical activity with serum lipid profile and physical fitness. A total of 537 healthy men aged 20-60 years were recruited in a quota sampling frame for measurement of physical activity energy expenditure at two different levels. The Minnesota Leisure Time Physical Activity Questionnaire was administered. Serum lipid and lipoprotein levels were measured, and all participants were given an exercise test. Physical activities with an intensity greater than 7 kcal/minute were significantly associated (p < 0.01) with a higher level of high density lipoprotein (HDL) cholesterol and a lower atherogenic index (total cholesterol:HDL cholesterol). Independently of other confounding variables, each average 100 kcal/day expended in leisure time physical activity with an intensity greater than 7 kcal/minute during the previous year was associated with an increase of 2.09 mg/dl (0.054 mmol/liter) in HDL cholesterol and a decrease of 0.23 in atherogenic index. However, only physical activity with an intensity greater than 9 kcal/minute was associated with decreases in total cholesterol, non-HDL cholesterol, and log(triglycerides). Better physical fitness was associated with physical activities of intensities above 5 kcal/minute. There is a threshold in the intensity of exercise associated with serum lipid profile (7 kcal/minute) and physical fitness (5 kcal/minute). Above the former threshold, the relation between amount of physical activity and lipid levels is linear for total cholesterol, HDL cholesterol, non-HDL cholesterol, and atherogenic index and is logarithmic for triglycerides.

Peripheral blood T-lymphocyte subsets in autoimmune thyroid disease

Interest in T-lymphocyte subsets has arisen because of their involvement in the autoimmune process. Contradictory results have been published in the literature about the number of peripheral blood lymphocyte subsets in autoimmune diseases. In order to investigate the number and distribution of peripheral blood lymphocyte subsets in autoimmune thyroid disease, the levels of total T-lymphocytes (CD3), T-helper (CD4) and T-suppressor/cytotoxic (CD8) lymphocytes were determined in 44 patients with Graves' disease (1), multinodular goiter (2) and Hashimoto's thyroiditis (3). All patients had high levels of antithyroglobulin and thyroid antiperoxidase (antimicrosomal) antibodies. The T subset levels were related to the functional thyroid status, measured as serum free thyroxine (FT4) and thyrotropin (TSH). Our data show the existence of a strong influence of functional status on CD3, CD4 and CD8 levels, as reflected in the significant correlations obtained with FT4 (negative) and TSH (positive). A significant decrease in all populations was observed in Graves' disease hyperthyroid patients. A decrease in the CD4/CD8 ratio in Hashimoto's thyroiditis hypothyroid patients was observed, in contrast to an increase in the ratio in autoimmune hyperthyroid patients. This points to the CD4/CD8 ratio as a differential characteristic between the two autoimmune (hypothyroid and hyperthyroid) entities, independent of free thyroxine levels. No significant correlation was found between antithyroid antibody levels and peripheral blood T-lymphocyte subsets or serum levels of FT4 and TSH.

[Etomidate perfusion in neurosurgery]

In this prospective study, 20 patients undergoing mean duration (2-3 h) neurosurgical operations on fossa cranii posterior, and cervical and dorsolumbar rachis, were induced with 0.3 mg/kg etomidate bolus dose. To maintain anesthesia, etomidate perfusions at 10 micrograms/kg/min (group I) and 20 microg/kg/min (group II) were administered. Fentanyl at fractionated doses was used as analgesic without association to nitrous oxide and relaxation was achieved with pancuronium bromide. Quality of hypnosis, changes in serum concentration of cortisol as well as hemodynamic and electrolyte changes were evaluated. Serum concentrations of cortisol, glucose, sodium and potassium were measured in basal state, and during perioperative and postoperative period. Hemodynamic status was monitored and side effects were recorded. Patients of group I presented signs of deficient hypnosis consisting of marked sympathetic response. When etomidate perfusion ceased, both groups presented serum concentrations of cortisol under the lower normal limit. Six hours after operation, mean serum concentration of cortisol in group 2 patients was significantly lower than in group I patients; in their samples, a dose-dependent recovery was detected. Serum glucose concentration increased during anesthesia and operation and serum electrolyte concentration remained within normal range during perioperative and postoperative periods. Our results demonstrate that a 20 micrograms/kg/min etomidate infusion is adequate to achieve neuroanesthesia when nitrous oxide administration is contraindicated.