Jasjeet S. Wasir

Waist circumference cutoff points and action levels for Asian Indians for identification of abdominal obesity

Objective:To test the validity of internationally accepted waist circumference (WC) action levels for adult Asian Indians.Design:Analysis of data from multisite cross-sectional epidemiological studies in north India.Subjects:In all, 2050 adult subjects >18 years of age (883 male and 1167 female subjects).Measurements:Body mass index (BMI), WC, waist-to-hip circumference ratio, blood pressure, and fasting samples for blood glucose, total cholesterol, serum triglycerides, and high-density lipoprotein cholesterol.Results:In male subjects, a WC cutoff point of 78 cm (sensitivity 74.3%, specificity 68.0%), and in female subjects, a cutoff point of 72 cm (sensitivity 68.7%, specificity 71.8%) were appropriate in identifying those with at least one cardiovascular risk factor and for identifying those with a BMI >21 kg/m2. WC levels of ⩾90 and ⩾80 cm for men and women, respectively, identified high odds ratio for cardiovascular risk factor(s) and BMI level of ⩾25 kg/m2. The current internationally accepted WC cutoff points (102 cm in men and 88 cm in women) showed lower sensitivity and lower correct classification as compared to the WC cutoff points generated in the present study.Conclusion:We propose the following WC action levels for adult Asian Indians: action level 1: men, ⩾78 cm, women, ⩾72 cm; and action level 2: men, ⩾90 cm, women, ⩾80 cm.

Waist Circumference Measurement by Site, Posture, Respiratory Phase, and Meal Time: Implications for Methodology

Waist circumference (WC) has been advocated as a simple, reliable, and cost‐effective measure to understand an individuals cardio‐metabolic risk. Although several protocols exist for measuring WC, the variation induced by a few factors has not been investigated. We compared several established and experimental WC measurement protocols to identify factors that may cause variations in WC measurement. In this cross‐sectional study, we examined the variations in the measurement of waist circumference (WC) measures carried out in 11 ways differing by anatomical site, posture, respiratory phase, and time since last meal, using repeated measure analysis of variance (using mixed models) after Tukey‐Kramer adjustment. We estimated the proportion of variance in percentage of body fat (%BF) and fat‐free mass (FFM) explained by each of the WC measures. We studied 123 apparently healthy Asian Indians (75 females), with mean (s.d.) age of 34 (8.7) years and BMI of 23.9 (4.8) kg/m2. Overall, the mean of WCs measured using the 11 protocols were statistically different. Further, post hoc analysis showed statistically significant, yet mostly small, differences between most of the pairs. No single WC measure explained highest variance in %BF or FFM for both genders. Although, the National Institute of Health (NIH), USA, protocol was convenient and may be less prone to errors, at present it does not control for many variables tested in this study. Measures of WC measured using different protocols were statistically different. We suggest that the site of measurement, posture, phase of respiration, and time since last meal should be standardized for the development of a protocol for measurement of WC for worldwide use.

Predictive Equations for Body Fat and Abdominal Fat With DXA and MRI as Reference in Asian Indians

Objective: To develop accurate and reliable equations from simple anthropometric parameters that would predict percentage of total body fat (%BF), total abdominal fat (TAF), subcutaneous abdominal adipose tissue (SCAT), and intra‐abdominal adipose tissue (IAAT) with a fair degree of accuracy.

Dietary Nutrients and Insulin Resistance in Urban Asian Indian Adolescents and Young Adults

Background: Asian Indians have a high prevalence of insulin resistance that may underlie their higher tendency to develop type 2 diabetes mellitus and early-onset atherosclerosis. Objective: To investigate the relationship between dietary nutrients and insulin resistance in Asian Indian adolescents and young adults. Design: Dietary nutrient intake values (24-hour dietary recall and monthly consumption data) and fasting serum insulin levels were studied in 352 (311 males and 41 females) healthy adolescents and young adults (mean age 18.0 ± 2.3 years; range 14–25 years). Bivariate and multivariate logistic regression analyses were performed with hyperinsulinemia as the outcome variable and various dietary nutrients and anthropometric variables as covariates. Results: Mean fasting serum insulin levels were 107.4 ± 35.0 pmol/l (36.5–230.4 pmol/l). The intake of polyunsaturated fatty acids (PUFAs) was higher, saturated fat and the ω–6 to ω–3 PUFA ratio were in the upper limit, and ω–3 PUFAs (% caloric intake, En) were lower than the recommended dietary allowance for Asian Indians. The PUFAs (% En), BMI, percent body fat and waist circumference were significantly higher in the hyperinsulinemic group compared with the normoinsulinemic group (p = 0.021, 0.0021, 0.0006, and 0.0041, respectively). Multiple regression analysis showed that the lowest tertile of ω–6 (<3% En) PUFA intake [adjusted OR (95% CI) = 0.3 (0.1–0.7)] and BMI [adjusted OR (95% CI) = 2.9 (1.4–6.0)] were the significant independent predictors of fasting hyperinsulinemia. Conclusion: For prevention and amelioration of insulin resistance in Asian Indian adolescents and young adults, it is prudent to have normal BMI and low intake of ω–6 PUFAs.

Centile values for serum lipids and blood pressure for Asian Indian adolescents

BackgroundReference data for plasma lipids and blood pressure are not available for Asian Indian adolescents. This study aimed to develop representative age- and sex- specific percentile reference data for serum lipids [total cholesterol (TC), triglycerides (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), non-HDL cholesterol] and blood pressure for urban Asian Indian adolescents aged 14–18 years. The sample consisted of 680 boys and 521 girls aged 14–18 years from the cross-sectional population survey, E pidemiological S tudy of A dolescents and Y oung Adults (ESAY) for whom the data for serum lipid levels and blood pressure were recorded. Smoothed age- and sex- specific 5th, 10th, 25th, 50th, 75th, 85th, 90th and 95th percentiles where derived using LMS regression.ResultsPercentile-based reference data for serum lipids and blood pressure are presented for adolescent Asian Indian boys and girls for the first time. Asian Indian adolescents had lower levels of serum TC, LDL-C and HDL-C and higher TG than their counterparts in the USA. Interesting trends in TC and HDL-C levels where observed, which might reflect changes in dietary pattern and physical activity in this age group in India.ConclusionThese reference data could be used to identify adolescents with an elevated risk of developing dyslipidemia, hypertension and cardiovascular disorders, to plan and implement preventive policies, and to study temporal trends.

Cutoffs of Abdominal Adipose Tissue Compartments as Measured by Magnetic Resonance Imaging for Detection of Cardiovascular Risk Factors in Apparently Healthy Adult Asian Indians in North India

BACKGROUND We aimed to define cutoffs of abdominal adipose tissue depots [total abdominal adipose tissue (TAAT), intraabdominal adipose tissue (IAAT), and abdominal subcutaneous adipose tissue (SCAT)] in adult Asian Indians in North India. METHODS We carried out a cross-sectional study that included 100 healthy adult Asian Indians. Anthropometric measurement (waist circumference, body mass index), metabolic profile [oral glucose tolerance test (OGTT), lipid profile], and imaging (for quantification of area of abdominal adipose tissue components using single slice magnetic resonance imaging) were done. Odds ratios (ORs) for detecting presence of greater than one cardiovascular (CV) risk factor were computed using tertiles of adipose tissue compartments and cutoffs were generated using receiver operating characteristics curve analysis. RESULTS The gender-specific cutoff limits for of TAAT, IAAT, and SCAT were 245.6 cm(2) (male) and 203.46 cm(2) (female), 135.3 cm(2) (male) and 75.73 cm(2) (female), and 110.74 cm(2) (male) and 134.02 cm(2) (female), respectively. For detection of CV risk factors, distinct gender differences were seen in ORs for SCAT [3.54 (95% confidence interval [CI], 1.10-11.46) and 6.6 (95% CI, 1.75-24.85) in males and females, respectively] but not for IAAT. CONCLUSIONS The cutoffs of TAAT, IAAT, and SCAT generated for the first time in Asian Indians could be used for metabolic research, interethnic comparisons of adiposity and CV risk factors, and optimal selection of anthropometric parameters.

Identification of insulin resistance in Asian Indian adolescents: classification and regression tree (CART) and logistic regression based classification rules

Objective  Biochemical measures for assessment of insulin resistance are not cost‐effective in resource‐constrained developing countries. Using classification and regression tree (CART) and multivariate logistic regression, we aimed to develop simple predictive decision models based on routine clinical and biochemical parameters to predict insulin resistance in apparently healthy Asian Indian adolescents.

Response to “Predictive Equations for Body Fat in Asian Indians”

The arbitrary nature of statistical models coupled with the large number of predictor variables that are usually used, makes interpreting the model and its bias(es) difficult. An alternative is to derive population specific equations. Choosing population categories and deciding the number of categories is not always easy and practicality might dictate that we accept a degree of inaccuracy/error. However, a systematic bias might lead to misleading conclusions; for example it might reduce the adiposity difference between rural and urban subjects. We believe that models based on known physiological or physical relationships between variables will fare better because such relationships should be invariant across populations.