Waist-to-Height Ratio as an Indicator of High Blood Pressure in Urban Indian School Children.

Objectives: To examine the utility of waist-to-height ratio to identify risk of high blood pressure when compared to body mass index and waist circumference in South Indian urban school children. Design: Secondary data analysis from a cross-sectional study. Settings: Urban schools around Bangalore, India. Participants: 1913 children (58.1% males) aged 6-16 years with no prior history of chronic illness (PEACH study). Methods: Height, weight, waist circumference and of blood pressure were measured. Children with blood pressure ≥90th percentile of age-, sex-, and height-adjusted standards were labelled as having high blood pressure. Results: 13.9% had a high waist-to-height ratio, 15.1% were overweight /obese and 21.7% had high waist circumference. High obesity indicators were associated with an increased risk of high blood pressure. The adjusted risk ratios (95% CI) of high systolic blood pressure with waist-to-height ratio, body mass index and waist circumference were 2.48 (1.76, 3.47), 2.59 (1.66, 4.04) and 2.38 (1.74, 3.26), respectively. Similar results were seen with high diastolic blood pressure. Conclusion: Obesity indicators, especially waist-to-height ratio due to its ease of measurement, can be useful initial screening tools for risk of high blood pressure in urban Indian school children.

Trier Social Stress Test in Indian Adolescents.

Objective: To test the Trier Social Stress Test for children (TSSTC) in a cohort of Indian adolescents. Design: Cohort study Setting: Holdsworth Memorial Hospital, Mysore, India. Participants: Adolescent children (N=273, 134 males; mean age 13.6 yrs) selected from an ongoing birth cohort; 269 completed the test. Intervention: Performance of 5-minutes each of public- speaking and mental arithmetic tasks in front of two unfamiliar ‘evaluators’. Outcome measures: Salivary cortisol concentrations were measured at baseline and at regular intervals after the TSST-C. Continuous measurements of heart rate, finger blood pressure, stroke volume, cardiac output and systemic vascular resistance were carried out before, during and for 10 minutes after the TSSTC using a finger cuff. Results: Cortisol concentrations [mean increment (SD): 6.1 (6.9) ng/mL], heart rate [4.6 (10.1) bpm], systolic [24.2 (11.6) mmHg] and diastolic blood pressure [16.5 (7.3) mmHg], cardiac output [0.6 (0.7) L/min], stroke volume [4.0 (5.6) mL] and systemic vascular resistance [225 (282) dyn.s/cm5] increased significantly (P<0.001) from baseline after inducing stress. Conclusions: The TSST-C produces stress-responses in Indian adolescents of a sufficient magnitude to be a useful tool for examining stress physiology and its relationships to disease outcomes in this population.

Insulin sensitivity and cardiac autonomic function in young male practitioners of yoga.

BACKGROUND: While yoga is thought to reduce the risk of chronic non-communicable diseases such as diabetes, there are no studies on insulin sensitivity in long term practitioners of yoga. We assessed insulin sensitivity and cardiac autonomic function in long term practitioners of yoga. METHODS: Fifteen healthy, young, male practitioners of yoga were compared with 15 young, healthy males who did not practice yoga matched for body-mass index. Fasting insulin sensitivity was measured in the fasting state by the hyperinsulinaemic-euglycaemic clamp. RESULTS: There were no significant differences between the groups in their anthropometry or body composition. However, the fasting plasma insulin was significantly lower in the yoga group. The yoga group was also more insulin sensitive (yoga 7.82 [2.29] v. control 4.86 [11.97] (mg/[kg.min])/(microU/ml), p < 0.001). While the body weight and waist circumference were negatively correlated with glucose disposal rate in the controls, there were no similar correlations in the yoga group. The yoga group had significantly higher low-frequency power and lower normalized high-frequency power. CONCLUSION: Long term yoga practice (for 1 year or more) is associated with increased insulin sensitivity and attenuates the negative relationship between body weight or waist circumference and insulin sensitivity.

Total body muscle mass estimation from bioelectrical impedance analysis & simple anthropometric measurements in Indian men.

BACKGROUND & OBJECTIVE: Skeletal muscle mass represents about 30-40 per cent of the total body weight, and has important roles in function and metabolism. Although newer methods of measuring muscle mass are accurate and sophisticated, there is a need for methods that can be used in low resource settings. Existing methods of predicting muscle mass are based on mid upper arm circumference (MUAC) measurements, sometimes corrected for triceps skinfold fat. The present study was undertaken to develop predictive equations for estimating muscle mass from simple and non-invasive methods such as bioelectrical impedance (BIA) and anthropometric measurements (circumferences and skinfold thickness) in Indian men. METHODS: BIA measurements and anthropometric measurements were carried out on 67 normal, healthy men between the ages of 18 and 45 yr. True muscle mass was measured from 24 h creatinine excretion. Multiple linear regression with step-wise forward selection was used to predict total muscle mass using measurements like height(2)/impedence, height and weight and using arm muscle area (AMA), thigh muscle area (TMA) and calf muscle area (CMA). RESULTS: The prediction equation for muscle mass (kg) using height(2)/impedance and height was - 12.347+ (0.363 x height(2)/impedance) + (0.122 x height) [R(2) = 0.55; Standard error of estimate (SEE) = 2.58 kg], while the equation using appendicular muscle area was 10.122 + (0.23 x AMA)+ (0.049 x TMA) [R(2) 0.36; SEE 3.07 kg]. INTERPRETATION & CONCLUSION: This study provides prediction equations for estimating muscle mass in healthy Indian males from simple non invasive methods such as BIA and anthropometric measurements such as circumferences and skinfold thickness. Further studies need to be done on a larger sample size and using an external group to validate the equations.

Nutritional status of affluent Indian school children: what and how much do we know?

OBJECTIVE: This paper reviews available literature on nutritional status of Indian school children 6-18 years from middle and high socio economic status (MHSES). METHODS: Literature search was conducted using Medline literature database search, followed by review of full length journal papers and unpublished materials such as research reports. RESULTS: Studies showed that anemia prevalence (hemoglobin concentration <120 g/L) ranged from 19 to 88% across five different cities in India. Other micronutrient deficiencies including, folate, riboflavin, niacin, vitamin C, vitamin A, and vitamin B12 were also present based on biochemical parameters in one study and clinical signs of deficiency in three other studies. Overweight and obesity were prevalent among 8.5-29.0% and 1.5-7.4% respectively among school children, as indicated by 11 studies. Predominant components in children's diet were cereals and pulses, followed by milk and milk products; the fruits and vegetables component was comparatively lower. CONCLUSION: Nutritional status of MHSES children in India needs attention especially with respect to the high prevalence of anemia, overweight and obesity. There are indications that micronutrient deficiencies exist, but sufficient data are lacking, in particular biochemical data. A current estimate, using well designed methodologies, of prevalence of micronutrient deficiencies and information on the etiology of anemia among children of MHSES groups would be valuable to help understand the nutritional status and extent of micronutrient malnutrition.

Measurement of 24 h energy expenditure in male tuberculosis patients.

BACKGROUND & OBJECTIVES: The total daily energy expenditure in patients with infectious disease is presumed to be high because of an increase in the basal metabolic rate (BMR), a reason for the weight loss observed in these patients. A reduction in daily physical activity, which may reduce the total daily energy expenditure. The aim of this study was to measure the free living total daily energy expenditure and physical activity of newly diagnosed hospitalized patients with tuberculosis using the labelled bicarbonate method. METHODS: In 6 healthy volunteers and 6 patients with newly diagnosed tuberculosis, 13C labelled bicarbonate method was used to measure free living total daily energy expenditure and physical activity. The 13C sodium bicarbonate (NaH13CO3) tracer was infused intravenously over a 48 h period and breath samples collected at regular intervals to estimate expired 13CO2. RESULTS: The patients had a 14 per cent increase in their BMR although they were not febrile at the time of measurement. However, their total daily energy expenditure was lower than that of the controls (mean value of 8.3 and 10.3 mJ/day respectively) and their physical activity level was also lower (mean 1.4 and 1.6 units respectively). INTERPRETATION & CONCLUSION: The total daily energy expenditure of afebrile patients with newly diagnosed tuberculosis is not higher than that of sedentary controls, despite an increased basal metabolic rate. It is possible that the observed weight loss in patients with tuberculosis is due to a reduced energy intake linked to anorexia associated with the disease. These findings may have relevance in nutritional treatment of chronic infections.

Bicarbonate kinetics in Indian males.

Measurement of rates of in vivo substrate oxidation such as that of glucose, fatty acids and amino acids, are based on tracer (14C or 13C) data, and often depend on the isotopic content of expired CO2. The recovery of tracer-labelled CO 2 generated from the oxidation of 13C labelled substrates may not be 100% over short term. This can lead to underestimation of oxidation rate of substrates, and consequently a correction for the incomplete recovery of tracer has to be applied by the determination of the recovery of 13CO2 in the breath during tracer bicarbonate infusions. We have studied the recovery of tracer-labelled bicarbonate using a bolus administration model, and further characterized kinetics of bicarbonate using a three-compartment model, to assess which compartmental fluxes changed during the change from a fasted state to fed state. Recovery of bicarbonate was lower at 69% and 67% (fasted and fed state) than the value of 71% and 74% found during earlier longer term of continuous infusions. During feeding, there was a 20-fold increase in the flux of bicarbonate between the central compartment and the compartment that was equivalent to the viscera. This study shows that the difference between the fasted and fed state recovery of tracer bicarbonate similar to that obtained with continuous infusions, and that bicarbonate fluxes show large changes between different compartments in the body depending on metabolic state.

Total energy expenditure & physical activity level in chronically energy deficient Indian males measured by the doubly labelled water technique.

Total energy expenditure (TEE) and basal metabolic rate (BMR) in the free-living state were measured in healthy south Indians, by the doubly labelled water (DLW) method. From these measurements, estimates of physical activity level (PAL) could be calculated. A total of 18 subjects were studied in 3 groups of 6 subjects each: Group I (urban controls), Group II (urban slum, chronically undernourished) and Group III (rural). The urban slum recruits were chronically energy deficient (CED), and had a low BMI (average 17.0 kg/m2), while the rural subjects had an average BMI of 18.1 kg/m2. The TEE measured by the doubly labelled water technique was 11.2, 7.1 and 12.2 MJ/day for Groups I, II and III respectively. The TEE was significantly lower in the urban CED group as obtained by the one way ANOVA. The estimates of TEE by the DLW technique were compared with estimates made by whole body calorimetry, in the urban groups of subjects. The TEE obtained by calorimetry was 10.3 +/- 1.6 and 7.3 +/- 0.2 MJ/day in Groups I and II respectively. There were no significant differences between the TEE measured by the two methods, in both the groups. The two methods also correlated well, and the mean difference between the methods, in both groups was -0.5 +/- 1.1 MJ/day, which was about 6 per cent of the value of TEE measured by the DLW method. The calculated PAL (by using TEE measured by DLW/BMR) was 1.79, 1.54 and 1.90 for Groups I, II and III respectively. The results showed that the activity of chronically energy deficient subjects, in urban slums, was reduced, and that this may be their method of conserving energy to maintain a stable body weight. Rural males had a high activity level, even though they had a low BMI.

Skeletal muscle endurance is reduced in chronically energy deficient adults.

Fifty eight adult males (well nourished; WN = 25, underweight; UW = 13, chronically energy deficient; CED = 20), aged 18 to 30 yr underwent an assessment of skeletal muscle function using a load cell based handgrip dynamometer coupled to a polygraph. WN subjects had higher handgrip strengths than either the UW or CED subjects (P < 0.05), though not when corrected for forearm muscle area or forearm volume. CED subjects fatigued faster than WN subjects during sustained maximal isometric contraction (P < 0.05) as well as during prolonged isotonic exercise (P < 0.05). During the latter, the onset of fatigue in the CED subjects was also faster than that in their anthropometrically similar UW controls. These data are consonant with reports of decreased productivity in undernourished adults during real life tasks.

Body fat topography in Indian and Tibetan males of low and normal body mass index.

Body fat topography was determined using anthropometric techniques in young, healthy, Indian and Tibetan adults. Indian subjects had significantly higher fat contents with greater abdominal obesity when compared with Tibetans matched for body mass index (BMI). This differential fat distribution may contribute, in part, to the greater cardiovascular risk of Indians. Using a cross sectional model, the data was also analysed to assess the probable changes in body fat topography with weight gain. This model suggests a preferential gain in abdominal subcutaneous fat as compared to other sites. This data may have implications while evaluating disease risks with weight gain.

Diet induced thermogenesis with oral & intravenous feeding in chronically undernourished human subjects.

The parasympathetic nervous system (PNS) has been shown to be important in the mediation of diet induced thermogenesis (DIT). Chronically energy deficient (CED) subjects have a high resting parasympathetic tone, which could lead to a greater than expected DIT. DIT was studied in chronically energy deficient adult men and healthy age-matched volunteers (6 controls, 7 CED subjects) with an isocaloric (600 kcal) meal given by the oral and intravenous (i.v.) routes on two consecutive days, on a crossover basis. The resting metabolic rate (RMR) and the DIT were measured over 6 h, along with cardiovascular, biochemical and anthropometric parameters. Anthropometrically (height, weight, fat free mass, body mass index, mid upper arm circumference and sum of skinfolds), the CED group differed significantly from the well-nourished control group. There were no significant differences between the two groups in the basal state for metabolic (RMR, oxygen consumption, respiratory quotient), cardiovascular [blood pressure (BP), heart rate, cardiac output], and biochemical (plasma glucose, insulin and norepinephrine) parameters. The CED group had a significantly higher DIT response for both meal types when compared to the controls, when expressed as an absolute value and as a percentage response. However, the response was not significant when corrected for the meal size and body weight. There were also no significant differences between the two meal types in each group for the metabolic, cardiovascular and biochemical parameters during the DIT period, although, in general, the oral meal gave a larger DIT response compared to the i.v. meal. Both groups predominantly oxidised fat during the fasted stage and switched to carbohydrate oxidation when fed. It appears that, the previously demonstrated higher tone in the PNS, does not make a significant contribution to the thermic response of a meal in these subjects.

Validation of expedient methods for measuring body composition in Indian adults.

The body composition of 99 men and 89 women from south India was estimated using hydrodensitometry, bioelectrical impedance and skinfold thickness. Comparisons of the hydrodensitometry (reference method) and skinfold methods showed that there were no significant differences between the methods, for estimates of fat free mass (FFM) and per cent fat. The mean difference between the estimates FFM (bias), from skinfold measurement and hydrodensitometry was small for both groups (+0.16 +/- 1.09 kg in men and +0.67 +/- 0.9 kg in women). The same trend was observed in per cent fat estimates (-0.37 +/- 2.04 in men and -1.49 +/- 2.28 in women), showing that the skinfold method can be used as an accurate and expedient method to determine body composition. The bioelectrical impedance method obtained a significantly lower FFM and higher body fat than the reference (hydrodensitometry) method. This could have been due to the use of an inappropriate equation derived from Western population studies. Hence, a new predictive equation, for the measurement of FFM by the bioelectrical impedance method was derived for this population, using the variables of height2/impedance and FFM measured by underwater weighing. The new equation for the bioelectrical impedance method then gave values of body composition which compared well (0.26 +/- 2.32 kg) in men and (0.36 +/- 2.49 kg) in women with the hydrodensitometry method.

Body composition by a three compartment model in adult Indian male and female subjects.

The body composition of 10 adult Indian male and female subjects was investigated by a three compartment model, using measurements of Total Body Water (TBW) by deuterium dilution, and of body density by hydrodensitometry. The three compartment model yielded significantly different (P < 0.005) estimates of percent body fat of 15.9+/-3.8 and 19.7+/-4.2% and of the Fat Free Mass (FFM) of 41+/-3.3 kg and 33.9+/-4.1 kg in the male and female subjects respectively. The hydration of the FFM was 0.704+/-0.032 in the males and 0.719+/-0.024 in the females; this difference was not signifcant between groups. The density of the FFM, measured from estimates of percent body fat by the 3 compartment approach and of body density by hydrodensitometry, was 1.107+/-0.014 in the males and 1.101+/-0.001 in the females with no significant differences between the groups. This study demonstrates differences in body composition between BMI matched healthy adult male and female subjects. Although there are significant differences for % Fat and FFM between the sexes, there are no significant differences in the hydration fraction and the density of the FFM.

Measurement of total energy expenditure by the doubly labelled water technique in free living Indians in Bangalore city.

Doubly labelled (2H2(18)O) water was used to determine the daily total energy expenditure (TEE) in the free living state of 6 adult, healthy, weight stable, male volunteers over a period of 21 days. The body weights of the subjects ranged from 42.3-70.4 kg. Isotope pool sizes and elimination rates were calculated from 18O and 2H enrichments in basal and daily (21 days) post dose urine samples using the multipoint slope intercept method after corrections for isotope fractionation. The physical activity level (PAL) of the subjects was also measured during the experiment as the ratio of measured TEE to measured basal metabolic rate (BMR). Simultaneous prediction of the total energy expenditure was also carried out by combining the measurements of BMR by indirect calorimetry, and daily physical activity level by 7 day recall. TEE calculated by the isotopic technique was 9.35 +/- 2.00 MJ/day, with an inter individual variation of 21.4 per cent. The measured BMRs in the subjects along with PALs obtained by recall, gave a total daily energy expenditure of 8.66 +/- 2.20 MJ/day with an inter individual variation of 25.4 per cent. The average BMR was 5.59 +/- 0.99 MJ/day and the average PAL (by recall) was 1.54 +/- 0.12. The inter individual variation of the BMR was 17.7 per cent and that of the recalled PAL was 7.9 per cent; the latter increased to 12.2 per cent when the PAL was calculated from the ratio of the measured TEE to the BMR. There was no significant differences between the methods (isotopic and predicted by BMR), although, the TEE obtained by the isotopic method was higher, by about 0.7 MJ/day, or 7.9 per cent, than the TEE predicted by BMR.

Thermal, cardiovascular & thermogenic responses to mild cold exposure in chronically energy deficient human subjects.

Thirteen young, male adults were investigated for thermal, cardiovascular and metabolic responses to truncal cooling for 40 min. The subjects were divided into two groups [well nourished controls (WN) and chronically energy deficient (CED)] on the basis of anthropometry and socio-economic status. The CED group had significantly greater reductions in peripheral forearm blood flow and surface finger tip temperatures on exposure to cold when compared to the well nourished controls. The CED group also showed a significant rise in oxygen consumption (3.4%), while no thermogenic response was observed in the WN controls. There was no fall in deep body temperature in either group. The study suggests that chronically energy deficient subjects thermoregulate appropriately on exposure to mild cold. The deficiency in insulative body fat is made up for by evoking greater peripheral vasoconstrictor responses as well as thermogenic mechanisms. The study suggests that on exposure to cold, thermoregulation takes precedence over energy conservation in chronically energy deficient subjects.

The 13C urea breath test to assess Helicobacter pylori infection in school children.

BACKGROUND: The 13C urea breath test was used in this study to establish it as a diagnostic tool as well as to assess the prevalence of Helicobactor pylori in a group of school children. METHODS AND RESULTS: In a group of 50 children studied, 82% were found to be positive for H. pylori by this test. The influence of diet in modifying the results of the test was also assessed. Relatively small errors were seen if adequate precautions were taken. CONCLUSION: Epidemiological studies are required to further quantify the magnitude of the prevalence of H. pylori in the Indian setting.

Total body water measurements by deuterium dilution in adult Indian males and females.

Total Body Water (TBW) was measured in a group of 20 healthy adult Indian men and 10 women by the deuterated water dilution technique and their body composition was determined by applying a hydration factor of 0.7194 for fat free mass (FFM). The TBW in the male subjects whose mean body weight was 49.8 +/- 6.7 kg, was 60.6 +/- 3.2% of body weight (range 55.8%-65.4%), from which a FFM of 41.9 +/- 6.1 kg (range 31.8 kg-51.3 kg) was obtained. Total body water in the group of 10 female subjects whose mean body weight was 42.7 +/- 4.9 kg, was 57.0 +/- 4.5% of body weight (range 52.5%-64.2%) from which a FFM of 34.0 +/- 5.1 kg (range 28.4 kg-39.4 kg) was obtained.

Nutritional assessment of marginally nourished surgical patients.

BACKGROUND. Anthropometric indices are known to be good indicators of nutritional status in the long term. However, there are conflicting reports about their effectiveness in short term assessments. METHODS. In 45 patients undergoing elective operations, the mid-arm circumference, biceps and triceps skin fold thickness and arm muscle area were measured. These were compared with haematological indices of nutritional status such as serum albumin, total protein and haemoglobin. The patients were divided into two groups based on their body mass index (< or > 18.5) or weight (< or > 52 kg). In another 10 patients, anthropometric and blood indices were studied pre- and postoperatively along with changes in body composition. RESULTS. When patients were grouped according to weight or body mass index, the anthropometric indices studied showed significant differences between the two groups, i.e. weight < 52 kg v. > 52 kg (mid-arm circumference: 22 +/- 3.3 cm v. 10 +/- 1.8 cm, p < 0.01; triceps skin fold thickness: 5.6 +/- 1.4 mm v. 10 +/- 4.9 mm, p < 0.01) although there were no differences in the blood indices. The 10 patients studied longitudinally were on energy-deficient intakes in the first postoperative week and lost lean tissue and body fat (-43 g, -33 g and -19 g protein and -78 g, -88 g and -97 g fat on postoperative days 1, 4 and 8 respectively). There was a variable response in terms of weight and body water. The measured anthropometric indices, however, showed no significant differences. CONCLUSIONS. Our results suggest that anthropometric indices are useful measures of nutritional status on a cross-sectional basis, whereas blood indices are not. Weight changes and anthropometric indices are not reliable guides to the short term nutritional course after an operation.