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Biomedical subjects

Mario Vaz

Publications and source records attributed to Mario Vaz.

At least 19 recordsLinked to original sources
PubMed2006

Effect of Caralluma fimbriata extract on appetite, food intake and anthropometry in adult Indian men and women.

Caralluma fimbriata is an edible cactus, used by tribal Indians to suppress hunger and enhance endurance. The effect of Caralluma extract was assessed in overweight individuals by a placebo controlled randomized trial. Fifty adult men and women (25-60 years) with a body mass index (BMI) greater than 25 kg/m2 were randomly assigned into a placebo or experimental group; the latter received 1 g of Caralluma extract per day for 60 days. All subjects were given standard advice regarding a weight reducing diet and physical activity. At the end of 30 and 60 days of intervention, blood glucose and lipids, anthropometric measurements, dietary intake and assessment of appetite was performed. Waist circumference and hunger levels over the observation period showed a significant decline in the experimental group when compared to the placebo group. While there was a trend towards a greater decrease in body weight, body mass index, hip circumference, body fat and energy intake between assessment time points in the experimental group, these were not significantly different between experimental and placebo groups. Caralluma extract appears to suppress appetite, and reduce waist circumference when compared to placebo over a 2 month period.

Adult↗
PubMed2006

Evaluating the suitability of prediction equations for lung function in Indian children: a practical approach.

OBJECTIVE: Although several prediction equations to evaluate peak expiratory flow rate (PEFR) of Indian children are available in literature, clinicians and researchers need to make a logical choice of which equation to use as reference. The aim was to demonstrate a practical approach to making such a logical choice by using prediction equations on our study population. METHODS: Eighteen linear regression equations generated on Indian children were chosen from available literature. PEFR measured on a Wright peak flow meter on 81 boys and 60 girls, aged between 8 and 13 years, was compared with the predicted values obtained from the equations. Data was systematically analyzed for the extent of over-estimation and under-estimation, correlation between the predicted and measured values and bias and limits of agreement using Bland-Altman plots. RESULTS: The correlation between observed and predicted values using the eighteen equations ranged between 0.616 and 0.797 (for all P < 0.001). The Bland-Altman plots indicated that for all but three equations in boys and three equations in girls, lower measured values of PEFR were associated with higher predicted values. A final choice of a reference prediction equation was based on a combination of factors which included a high correlation between actual and predicted PEFR values, the bias of the estimate, the limits of agreement and the extent to which equations over or under-estimated PEFR. CONCLUSION: A practical approach to evaluate the applicability of prediction equations on an independent data set has been demonstrated.

Adolescent↗
PubMed2005

A compilation of energy costs of physical activities.

OBJECTIVES: There were two objectives: first, to review the existing data on energy costs of specified activities in the light of the recommendations made by the Joint Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) Expert Consultation of 1985. Second, to compile existing data on the energy costs of physical activities for an updated annexure of the current Expert Consultation on Energy and Protein Requirements. DESIGN: Electronic and manual search of the literature (predominantly English) to obtain published data on the energy costs of physical activities. The majority of the data prior to 1955 were obtained using an earlier compilation of Passmore and Durnin. Energy costs were expressed as physical activity ratio (PAR); the energy cost of the activity divided by either the measured or predicted basal metabolic rate (BMR). RESULTS: The compilation provides PARs for an expanded range of activities that include general personal activities, transport, domestic chores, occupational activities, sports and other recreational activities for men and women, separately, where available. The present compilation is largely in agreement with the 1985 compilation, for activities that are common to both compilations. CONCLUSIONS: The present compilation has been based on the need to provide data on adults for a wide spectrum of human activity. There are, however, lacunae in the available data for many activities, between genders, across age groups and in various physiological states.

Activities of Daily Living↗
PubMed2004

How sedentary are people in "sedentary" occupations? The physical activity of teachers in urban South India.

AIMS: The aim of this study was to assess the total and occupational physical activity status of school and college teachers in Bangalore, South India and to evaluate the use of "job description" as an indicator of occupational physical activity. METHOD: A self-administered questionnaire was given to a convenience sample of 198 (25 males and 173 females) school and college teachers. RESULTS: Despite the categorization of "teacher" in India as "sedentary", our data indicate that the overall physical activity status of teachers varies considerably and is dependent on non-occupational physical activity, such as household chores and discretionary exercise. Thus, only 12% of teachers were truly sedentary, based on computations of the contributions of all measured physical activity domains, while 10% were heavily active. The contribution of other physical activity domains to the overall physical activity status in our data set was dependent on gender; in women, the energy expenditure related to household chores was 4-fold higher than in men (P < 0.01), while in men, energy expenditure related to discretionary exercise was 3-fold higher than in women (P < 0.01). CONCLUSIONS: This study highlights the problems associated with extrapolating occupational activity using job descriptors to overall physical activity status. The findings have implications in epidemiological studies which use occupational activity as a surrogate for overall physical activity status. However, the impact of potential misclassifications will need to be assessed within a socio-cultural context.

Adult↗
PubMed2004

Physical activity and risk of coronary heart disease in India.

BACKGROUND: Physical exercise has been inversely associated with coronary heart disease (CHD) risk in Western populations; however, the association has not been examined in India where physical inactivity levels in urban areas are now comparable with the West. METHODS: We conducted a hospital-based case-control study and collected data from 350 cases of acute myocardial infarction and 700 controls matched on age, gender, and hospital in New Delhi and Bangalore. We used conditional logistic regression to control for the matching and other risk factors. RESULTS: Of the controls, 48% participated in some form of leisure-time exercise compared with 38% of cases. In age- and sex-adjusted analyses, people in the highest level of leisure-time exercise (>145 metabolic equivalents [MET]-minutes per day, equivalent to 36 minutes of brisk walking per day) had a relative risk of 0.45 (95% CI: 0.31, 0.66) compared with non-exercisers. Multivariate adjustment for other risk factors did not substantially alter the association. We observed a positive association between non-work sedentary activity and CHD risk; people with >3.6 hours per day of sedentary activity (for example, television viewing) had an elevated risk of 1.88 (95% CI: 1.09, 3.20) compared with <70 minutes per day in multivariate analysis. CONCLUSION: Leisure-time exercise, including as much as 35-40 minutes per day of brisk walking, was protective for CHD risk and sedentary lifestyles were positively associated with risk of CHD. Given limited resources for care of CHD in India and the important role of physical exercise in disease risk in urban India, improvements in physical activity should be promoted.

Adult↗
PubMed2004

Diet and risk of ischemic heart disease in India.

BACKGROUND: Ischemic heart disease (IHD) is a leading cause of death in India. Dietary changes could reduce risk, but few studies have addressed the association between diet and IHD risk in India. OBJECTIVE: The goal was to address the association between diet and IHD risk among Indians in New Delhi (northern India) and Bangalore (southern India). DESIGN: We collected data from 350 cases of acute myocardial infarction and 700 controls matched on the basis of age, sex, and hospital as part of a hospital-based case-control study in 8 hospitals. Long-term dietary intake was assessed by using food-frequency questionnaires developed for New Delhi and Bangalore. We used conditional logistic regression to control for the matching factors and other predictors of risk. RESULTS: We observed a significant and dose-dependent inverse association between vegetable intake and IHD risk. The inverse association was stronger for green leafy vegetables; in multivariate analysis, persons consuming a median of 3.5 servings/wk had a 67% lower relative risk (RR: 0.33; 95% CI: 0.17, 0.64; P for trend = 0.0001) than did those consuming 0.5 servings/wk. Controlling for other dietary covariates did not alter the association. Cereal intake was also associated with a lower risk. Use of mustard oil, which is rich in alpha-linolenic acid, was associated with a lower risk than was use of sunflower oil [for use in cooking: RR: 0.49 (95% CI: 0.24, 0.99); for use in frying, RR: 0.29 (95% CI: 0.13, 0.64)]. CONCLUSION: Diets rich in vegetables and use of mustard oil could contribute to the lower risk of IHD among Indians.

Adult↗
PubMed2004

Effect of age and nutritional status on heart rate responses to cough and maximum handgrip.

Autonomic nerve activity can be assessed using simple bed side tests such as cough and maximum hand grip (MHG). The alterations in these tests are, however, poorly documented in physiological states. The present study aimed to uncover the effect of nutritional status and age on these tests. 93 male adults were divided into normal body mass index (BMI) (BMI; 18.5 to 25 kg/m2; young 18-30 yrs, n=28; old >60 yrs, n=25) and low BMI (BMI; <18.5 kg/m2; young 18-30 yrs, n=19; old >60 yrs, n=14) groups. The younger subjects showed a significantly higher heart rate response to cough and MHG in both normal and low BMI groups as compared to the older subjects (P<0.01). However, there were no significant differences for the heart rate responses to cough and MHG between the low and normal BMI groups either in the young or in the elderly. The data suggest that while the heart rate response to cough and MHG are useful tests of vagal activity to the heart when expected differences are large, they may be of limited use in uncovering more subtle changes.

Adult↗
PubMed2003

Heart rate variability and baroreflex sensitivity are reduced in chronically undernourished, but otherwise healthy, human subjects.

Alterations in autonomic nerve activity in subjects in a chronically undernourished state have been proposed, but have been inadequately documented. The present study evaluated heart rate and systolic blood pressure variability in the frequency domain in two underweight groups, one of which was undernourished and recruited from the lower socio-economic strata [underweight, undernourished (UW/UN); n =15], while the other was from a high class of socio-economic background [underweight, well nourished (UW/WN); n =17], as well as in normal-weight controls [normal weight, well nourished (NW/WN); n =27]. Baroreflex sensitivity, which is a determinant of heart rate variability, was also assessed. The data indicate that total power (0-0.4 Hz), low-frequency power (0.04-0.15 Hz) and high-frequency power (0.15-0.4 Hz) of RR interval variability were significantly lower in the UW/UN subjects ( P <0.05) than in the NW/WN controls when expressed in absolute units, but not when the low- and high-frequency components were normalized for total power. Baroreflex sensitivity was similarly lower in the UW/UN group ( P <0.05). Heart rate variability parameters in the UW/WN group were generally between those of the UW/UN and NW/WN groups, but were not statistically different from either. The mechanisms that contribute to the observed differences between undernourished and normal-weight groups, and the implications of these differences, remain to be elucidated.

Adolescent↗
PubMed2002

Decreased chaos of heart rate time series in children of patients with panic disorder.

This study examined the differences of heart rate variability measures between children of parents with panic disorder and children of healthy controls using linear as well as nonlinear techniques. Supine and standing heart rate variability indices were measured in all children using power spectral analysis and a measure of chaos, the largest Lyapunov exponent (LLE) of heart rate time series. No significant differences emerged between the children of panic disorder parents and children of normal controls on any of the spectral heart rate variability measures. However, children of patients with panic disorder had significantly lower LLE of heart rate time series in supine posture, suggesting a relative decrease of cardiac vagal function in this group of children. This suggests a possible heritable effect of certain measures of heart rate variability, as previous studies showed decreased heart rate variability in patients with panic disorder using spectral as well as nonlinear techniques. Recent evidence also suggests that some of these nonlinear measures are superior or of additional value to the traditional time and frequency domain measures of heart rate variability to predict serious ventricular arrhythmias and sudden death.

Anxiety, Separation↗
PubMed2002

Effect of standing on short term heart rate variability across age.

This study examined the response of heart rate variability measures to standing in three age groups of male subjects: Children (6-11 years), young adults (20-30 years) and elderly (60-70 years). Supine and standing heart rate variability indices were measured in all the subjects using power spectral analysis. The effect of posture on heart rate variability was assessed using the change in heart rate variability measures over resting values during the first 2 min following active standing. There was an attenuated response in normalized low frequency (LF) and high frequency (HF) power to standing in the elderly as compared with young adults and children. Heart rate variability responses to standing were highest in the young adults, followed by the children and the elderly, although the differences between the young adults and children were not significant. More studies are needed to characterize HRV responses to posture in children.

Adolescent↗
PubMed2002

A comparative study of tests of cardiac parasympathetic nervous activity in healthy human subjects.

Conventional tests of cardiac parasympathetic nervous system (PNS) activity were compared with the high frequency component of the heart rate power spectrum in a heterogenous group of normal subjects encompassing a wide age range. The data suggest that the linear associations between the various conventional tests of parasympathetic nervous activity even when statistically significant, were relatively modest, with r values ranging from 0.23 to 0.53. Three of the five conventional tests of parasympathetic nervous activity were significantly correlated (r = 0.33 to 0.46) with the absolute high frequency power of RR variability. However, these relationships were poorer and non-significant when the high frequency power spectrum was normalized for total power (r = 0.06 to 0.19, NS). An evaluation of the heart rate responses to cough and a single maximal hand grip indicated that the responses were repeatable but that the extent to which these manoeuvres induced vagally mediated cardioacceleration was significantly lesser than the other conventional tests of PNS activity. Taken together, the data suggest that despite the advent of heart rate variability measures, it is advisable to use multiple tests of parasympathetic nervous activity while evaluating autonomic dysfunction, since, despite the specificity of the tests, there is a variable correlation between them.

Adolescent↗
PubMed2002

Lysine requirements of healthy adult Indian subjects receiving long-term feeding, measured with a 24-h indicator amino acid oxidation and balance technique.

BACKGROUND: The mean lysine requirement of healthy Indian subjects was estimated from short-term experimental diet periods to be 29 mg x kg(-1) x d(-1), which is higher than the 1985 FAO/WHO/UNU upper requirement of 12 mg x kg(-1) x d(-1). OBJECTIVE: Our objective was to confirm our proposed requirement of 29 mg x kg(-1) x d(-1) by extending the diet period to 21 d and by using 4 test lysine intakes (12, 20, 28, and 36 mg x kg(-1) x d(-1)) and a 24-h indicator amino acid oxidation and balance approach. DESIGN: During two 21-d diet periods, 18 healthy Indian men were randomly assigned to receive 12 and 28 or 20 and 36 mg lysine x kg(-1) x d(-1) as part of an L-amino acid diet. At 1800 on days 6 and 20, [(13)C]leucine was infused over 24 h to assess leucine oxidation and daily leucine balance at each test intake. RESULTS: Leucine oxidation, balance, and flux did not differ significantly between days 7 and 21. Twenty-four-hour leucine oxidation was lower at lysine intakes of 28 and 36 mg than at 12 and 20 mg. Leucine balances at lysine intakes of 12 and 20 mg were negative and significantly less than equilibrium (P < 0.01) and lower (P < 0.02) than balances at 28 and 36 mg lysine. Two-phase regression analysis indicated a breakpoint at 31 mg lysine x kg(-1) x d(-1) in the relation between lysine intake and 24-h leucine oxidation and balance. CONCLUSIONS: Full adaptation to a low lysine intake occurs within 7 d. The previously proposed tentative mean lysine requirement for Western subjects of 30 mg x kg(-1) x d(-1) is confirmed for healthy Indian adults.

Adult↗
PubMedDate not supplied

Use of rice bran oil in patients with hyperlipidaemia.

BACKGROUND: The quantity and type of dietary fat is known to affect plasma lipid concentration and hence the choice of cooking oil is important to lower the risk of coronary heart disease. Rice bran oil, which was not popular worldwide, is slowly being recognized as a 'healthy' oil in India. We assessed if rice bran oil had hypolipidaemic effects in subjects with elevated lipid levels. METHODS: The study had a cross-over design with subjects (n = 14) randomly assigned to consume either rice bran oil or refined sunflower oil in their homes, for a period of 3 months (period 1). After a washout period of 3 weeks, they were crossed over to the other oil (period 2). The serum lipid values were estimated at the beginning, on day 45 and day 90 of each phase. Additional parameters assessed included anthropometry, dietary and physical activity patterns. RESULTS: The use of rice bran oil significantly reduced plasma total cholesterol and triglyceride levels compared with sunflower oil. The reduction in plasma LDL-cholesterol with rice bran oil was just short of statistical significance (p = 0.06). HDL-cholesterol levels were unchanged. CONCLUSION: The use of rice bran oil as the main cooking oil significantly reduced serum cholesterol and triglyceride levels. The use of rice bran oil together with dietary and lifestyle modifications may have implications for reducing the risk of cardiovascular disease.

Adult↗