Evaluation of waist-to-height ratio as a predictor of insulin resistance in non-diabetic obese individuals. A cross-sectional study

ABSTRACT BACKGROUND: Insulin resistance (IR) and progressive pancreatic β-cell dysfunction have been identified as the two fundamental features in the pathogenesis of obesity and non-insulin-dependent diabetes mellitus. We aimed to investigate correlations between anthropometric indices of obesity and IR in non-diabetic obese individuals, and the cutoff value from receiver operating characteristic (ROC) curve analysis. DESIGN AND SETTING: Cross-sectional study conducted in a private clinic. METHODS: We included obese individuals (body mass index, BMI ≥ 30 kg/m2) with no diabetes mellitus (fasting glucose levels ≤ 126 mg/dl). The participants were evaluated for the presence of cardiovascular risk factors and through anthropometric measurements and biochemical tests. Furthermore, IR was assessed indirectly using the homeostatic model assessment (HOMA)-IR and HOMA-β indexes. The area underthe curve (AUC) of the variables was compared.The sensitivity, specificity and cutoff of each variable for diagnosing IR were calculated. RESULTS: The most promising anthropometric parameters for indicating IR in non-diabetic obese individuals were waist-to-height ratio (WHtR), waist circumference (WC) and BMI. WHtR proved to be an independent predictor of IR, with risk increased by 0.53% in HOMA-IR, 5.3% in HOMA-β and 1.14% in insulin. For HOMA-IR, WHtR had the highest AUC value (0.98), followed by WC (0.93) and BMI (0.81). For HOMA-β, WHtR also had the highest AUC value (0.83), followed by WC (0.75) and BMI (0.73).The optimal WHtR cutoff was 0.65 for HOMA-IR and 0.67 for HOMA-β. CONCLUSION: Among anthropometric obesity indicators, WHtR was most closely associated with occurrences of IR and predicted the onset of diabetes in obese individuals.

Use of combined method, accelerometer and international physical activity questionnaire, to determinate occurence of physical inactivity in adults

Abstract Aim Evaluate and compare the proportion of PI and associated factors by IPAQ questionnaire, triaxial accelerometry and the combination of both. Adults aged ( 18 years were enrolled (n = 250). Methods We considered PI as < 600 MET-min/wk in the IPAQ total score, < 150 min/wk of moderate-to-vigorous physical activity in 7 days accelerometry, and the combination of both criteria. Clinical assessment, spirometry, cardiopulmonary exercise test, bioelectrical impedance, isokinetic dynamometry, postural balance, and six-minute walk test were also performed. For participants practicing aquatic, martial arts or cycling, only the IPAQ criterion was considered. Results Proportions of PI were significantly different among methods (IPAQ, 10%; accelerometry, 20%; combination, 25%). After multivariate logistic regressions, PI was determined by age, sex, educational level, risk factors for cardiovascular disease, lean body mass, cardiorespiratory fitness, and postural balance. Conclusion Thus, the combined method for determining PI and associated factors in adults showed great validity, indicating that questionnaires and accelerometers are complementary and should be utilized in combination in epidemiological studies.(AU)