Homeostasis Model Assessment Equation Research Articles

Accelerometer-Measured Physical Activity, Fitness and Indicators of Cardiometabolic Risk among Rural Adolescents: A Cross-Sectional Study at 15-Year Follow-up of the MINIMat Cohort.

Little is known about the relationship of physical activity (PA) and fitness with cardiometabolic risk among rural adolescents in low- and middle-income countries. Thus, we examined the associations of PA and fitness with selected cardiometabolic indicators along with potential gender-based differences in a birth cohort of rural adolescents from southeast Bangladesh. We utilized data from the 15-year follow-up of Maternal and Infant Nutrition Interventions in Matlab (MINIMat) cohort (n = 2253). Wrist-worn ActiGraph wGT3x-BT accelerometers were used to estimate sedentary time (ST) and PA. Fitness was assessed using: handgrip strength, standing long jump, and Chester Step Test. Anthropometric parameters, systolic blood pressure (SBP), and fasting lipid, insulin and glucose levels were measured. We calculated insulin resistance using the Homeostasis Model Assessment equation (HOMA-IR). Linear regression and isotemporal substitution models were fitted. The adolescents spent 64min/day (inter-quartile range: 50-81) in moderate-to-vigorous physical activity (MVPA). A 10-minute-per-day higher vigorous PA (VPA) was associated with: 4.9% (95% confidence interval (CI): 2.9-6.8%) lower waist circumference (WC), 3.2 mmHg (95% CI: 1.5-4.8) lower SBP, 10.4% (95% CI: 2.9-17.3%) lower TG, and 24.4% (95% CI: 11.3-34.9%) lower HOMA-IR. MVPA showed similar associations of notably smaller magnitude. Except for WC, the associations were more pronounced among the boys. Substituting ST with VPA of equal duration was associated with lower WC, SBP, triglyceride and HOMA-IR. Grip strength was favorably associated with all indicators, displaying considerably large effect sizes. Our findings indicated beneficial roles of PA- particularly VPA- and muscular fitness in shaping cardiometabolic profile in mid-adolescence. VPA and grip strength may represent potential targets for preventive strategies tailored to adolescents in resource-limited settings.

Dietary patterns and indicators of cardiometabolic risk among rural adolescents: A cross-sectional study at 15-year follow-up of the MINIMat cohort.

Diet being a modifiable factor, its relationship with cardiometabolic risk is of public health interest. The vast majority of studies on associations of dietary patterns with cardiometabolic risk indicators among adolescents are from high-income countries and urban settings. We sought to describe dietary patterns and examine their associations with selected cardiometabolic risk indicators-waist circumference (WC), systolic blood pressure, fasting lipid profile and insulin resistance-along with its gender stratification among adolescents in a low-income, rural setting. This cross-sectional study utilized data from the 15-year follow-up of the Maternal and Infant Nutrition Interventions in Matlab (MINIMat) cohort in southeast Bangladesh. The children who were born as singletons to the mothers randomized in the MINIMat trial and had valid birth anthropometrics were eligible for the follow-up. We employed a single, qualitative 24-hour recall to assess diet. Dietary patterns were derived from simple K-means cluster analysis, and calculation of dietary diversity score (DDS) using a validated instrument. Anthropometric parameters and systolic blood pressure were recorded. Fasting plasma triglyceride, total cholesterol, low- and high-density lipoproteins, insulin and glucose levels were measured. We calculated insulin resistance using the Homeostasis Model Assessment equation (HOMA-IR). Three right-skewed outcome variables were natural log (Ln) transformed: WC, triglyceride and HOMA-IR. Omnibus and gender-specific multiple linear regression models were fitted. Among 2,253 adolescents (52.1% girls, 7.1% overweight/obese), we identified four diet clusters: Traditional, Fish-dominant, Meat-dominant, and High-variety. No significant associations were found between the clusters and indicators. On gender-stratification, triglyceride levels were lower among boys in the Fish-dominant (Ln-triglyceride βadjusted: -0.09; 95% confidence interval (CI): -0.15, -0.02) and Meat-dominant (Ln-triglyceride βadjusted: -0.08; 95% CI: -0.15, -0.004) clusters than among boys in the Traditional cluster. Compared to boys in the bottom quartile of DDS, boys in the top quartile had 2.1 mm of Hg (95% CI: 0.5, 3.6) higher systolic blood pressure and 1.9% (95% CI: 0.01-3.8%) higher WC. While statistically significant, the gender-specific differences in triglyceride, systolic blood pressure, and waist circumference across dietary patterns were small. Associations between dietary patterns and cardiometabolic risk indicators may require a time lag beyond mid-adolescence to manifest in a rural setting. Prospective studies are warranted to delineate the magnitude and direction of those associations.

25-Hydroxycholecalciferol levels and its equation with lipid parameters and Insulin sensitivity in obese and non-obese young adults: A pilot study

Abstract Introduction: Vitamin D deficiency and Obesity are the two prevailing health issues of the globe, with India being no exception. The sub optimal Vitamin D levels is associated with an elevated risk of a number of chronic disorders including malignancy, inflammation and autoimmune diseases. Obesity breeds metabolic disharmony. Recent data reports Vitamin D deficiency being more prevalent among the obese. Objective: This study is undertaken to see the association of Vitamin D levels with Body Mass Index (BMI), Lipid parameters and Insulin resistance in a sample population representing the urban Indian youth. Materials and Method: Fifty five apparently healthy young adults of 18 to 22 years age were recruited in this study and their serum 25-hydroxycholecalciferol(25OHD), serum insulin, Total Cholesterol, High Density lipoprotein-cholesterol (HDL-c), Low Density lipoprotein- cholesterol (LDL-c) and Triglyceride (TGL) levels were estimated. Insulin resistance(IR) was derived using the Homeostasis Model Assessment equation. Based on BMI, the participants were divided into Obese group with BMI ≥ 25 (n=21) and non-obese group with BMI < 25 (n=34). Result: 25OHD levels were almost same in both Groups (Obese11.1 ± 4.6 ng/ml and non-obese 11.0 ± 5.2 ng/ml). Serum total cholesterol, VLDL and insulin levels were significantly increased in the Obese group(p= 0.005, p= 0.015 and p=0.054 respectively) when compared to the non-obese group. We found statistically significant association between 25-hydroxycholecalciferol (25OHD) and TGL/HDL ratio in the Obese group. Conclusion: In this pilot study we have unravelled the subtle onset of metabolic derangement in Obese individuals with Vitamin D deficiency.

Association of matrix γ-carboxyglutamic acid protein levels with insulin resistance and Lp(a) in diabetes: A cross-sectional study.

The risk of cardiovascular disease (CVD) and mortality is increased in patients with chronic kidney disease (CKD), with a background role of vascular calcification in the development of CVD also reported. Studies have demonstrated that high lipoprotein(a) (Lp(a)) levels accelerate the development of atherosclerolsis and are potentially involved in the vascular calcification. Matrix Gla Protein (MGP) seems to play an important role in vascular calcification. The aim of the study was to examine the potential association of MGP concentrations with Lp(a) and insulin resistance. The study involved 100patients divided in four groups: 25 with both CKD stage 4 and Type2 Diabetes (DM) (Group-A), 25 with CKD4 without DM (Group-B), 25 non uremic patients with DM (Group-C) and 25 healthy subjects (Group-D). Serum glucose, Lp(a), MGP, plasma HBA1c and insulin were measured in all patients. Insulin resistance was estimated by the homeostasis model assessment equation (HOMA-IR). A significant positive linear association between MGP and Lp(a) levels (r=0.272, p=0.006) was noted, as well as between MGP and HOMA-IR levels (r=0.308, p=0.002). However, no significant linear association between Lp(a) and HOMA-IR levels was recorded. A similar positive association between MGP and insulin levels (r=0.204, p=0.042) was also found. This study concluded that diabetes coexisting with renal disease leads to extreme vascular calcification expressed by elevated MGP levels, resulting in higher frequency of cardiovascular disease in comparison to CKD patients without diabetes. The detected Lp(a) and MGP association in CKD4 patients may also represent the key to the complicated mechanism of their coexisting accelerated atherosclerosis and vascular calcification.

Maternal vitamin D status during pregnancy and body composition and cardiovascular risk markers in Indian children: the Mysore Parthenon Study

Metabolic consequences of vitamin D deficiency have become a recent research focus. Maternal vitamin D status is thought to influence musculoskeletal health in children, but its relation with offspring metabolic risk is not known. We aimed to examine the association between maternal vitamin D status and anthropometric variables, body composition, and cardiovascular risk markers in Indian children. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured at 28-32 wk gestation in 568 women who delivered at Holdsworth Memorial Hospital, Mysore, India. Anthropometric variables, glucose and insulin concentrations, blood pressure, and fasting lipid concentrations were measured in the offspring at 5 and 9.5 y of age. Muscle-grip strength was measured by using a hand-held dynamometer at age 9.5 y. Arm-muscle area was calculated as a measure of muscle mass. Fasting insulin resistance was calculated by using the homeostasis model assessment equation. Sixty-seven percent of women had vitamin D deficiency [serum 25(OH)D concentration <50 nmol/L]. At ages 5 and 9.5 y, children born to vitamin D-deficient mothers had smaller arm-muscle area in comparison with children born to mothers without deficiency (P < 0.05). There was no difference in grip strength between offspring of women with and without vitamin D deficiency. At 9.5 y, children of vitamin D-deficient mothers had higher fasting insulin resistance than did children of nondeficient women (P = 0.04). There were no associations between maternal vitamin D status and other offspring risk factors at either age. Intrauterine exposure to low 25(OH)D concentrations is associated with less muscle mass and higher insulin resistance in children.

Detectable HIV Viral Load Is Associated With Metabolic Syndrome

The aim of our study was to assess the association between HIV viral load (HIV-VL) and metabolic syndrome (MS) in a cohort of HIV-infected patients. This is a cross-sectional study including 1324 consecutive HIV-infected patients on stable antiretroviral therapy regimens. Variables significantly associated with MS in univariate analysis were: age [mean +/- SD: 47.04 +/- 7.41 vs 44.07 +/- 6.82, (P < 0.0001)]; male sex [224 (69.35%) vs 614 (61.34%) (P = 0.009)]; Apo B (mg/dL) [111.51 +/- 29.64 vs 100.57 +/- 31.22, (P < 0.0001)]; homeostasis model assessment equation [median (interquartile range), 5.14 (3.00-8.15) vs 2.95 (1.93-4.57), (P < 0.0001)]; body mass index [25.17 +/- 4.40 vs 22.80 +/- 3.38, (P < 0.0001)]; protease inhibitor current use (%) [199 (61.61) vs 529 (52.85), (P = 0.006)]; and log10 HIV-VL [2.17 +/- 0.94 vs 2.02 +/- 0.79, (P = 0.0048)]. MS associated variables in multivariable analysis were: log10 HIV-VL [odds ratio (OR): 1.25; P = 0.003], age (per 10-year increment) [OR: 1.60; P < 0.0001], homeostasis model assessment equation > or =3.8 [OR: 2.77; P < 0.0001]. Persistent viremia is a significant predictor for the development of MS. Viral control through effective antiretroviral therapy is paramount not only for the control of HIV disease progression but also for the prevention of MS and associated cardiovascular disease.

Metabolic rate and vascular function are reduced in women with a family history of type 2 diabetes mellitus

Metabolic and vascular abnormalities have been found in individuals with type 2 diabetes mellitus (T2D). Family history is often associated with increased risk of the development of T2D. We sought to determine if young, sedentary, insulin-sensitive individuals with a family history of T2D (FH+) have a reduced resting energy expenditure (REE) and vascular endothelial function compared with individuals who have no family history of T2D (FH−). The REE was determined in 18 FH+ individuals and 15 FH− individuals using indirect open-circuit calorimetry. Vascular endothelial function was measured via flow-mediated dilation (FMD) of the brachial artery. C-reactive protein and interleukin-6 were also measured to look at vascular inflammation. Body composition was measured via bioelectrical impedance analysis to determine fat-free mass and fat mass for each individual. Insulin resistance was calculated using the homeostasis model assessment equation and fasting insulin and glucose concentrations. Subjects (n = 42) were approximately 26 years old and had normal fasting serum insulin or glucose concentrations. The REE normalized for body weight (kilocalories per day per kilogram body weight) was significantly reduced in the FH+ women compared with FH− women ( P < .001) but not in the men. The FMD was significantly reduced (34.3%) in the FH+ group compared with the FH− in women ( P = .002). However, no between-group difference in FMD was present in male subjects ( P = .376). Young, healthy, insulin-sensitive women with a family history of T2D have reduced whole-body metabolic rate and vascular endothelial function compared with those with no family history of disease. These differences in whole-body metabolic rate and vascular endothelial function were not present in male subjects.

High postprandial triglyceridemia in patients with type 2 diabetes and microalbuminuria

Microalbuminuria (MA) is an independent risk factor for atherosclerosis in patients with type 2 diabetes mellitus (T2DM). Postprandial lipemia is also associated with excess cardiovascular risk. However, the association between MA and postprandial lipemia in diabetes has not been investigated. A total of 64 patients with T2DM, 30 with and 34 without MA, were examined. Plasma total triglycerides (TGs), triglycerides contained in chylomicrons (CM-TG), and TGs in CM-deficient plasma were measured at baseline and every 2 h for 6 h after a mixed meal. Postheparin LPL and HL activities were also determined. Plasma levels of apolipoprotein A-V (apoA-V), apoC-II, and apoC-III were measured in the fasting state and 2 h postprandially. Patients with MA had higher postprandial total TG levels than those without MA (P < 0.001); this increase been attributed mainly to CM-TG. LPL activity and fasting concentrations of the measured apolipoproteins were not different between the studied groups, whereas HL activity was higher in the patients with MA. ApoC-II and apoC-III levels did not change postprandially in either study group, whereas apoA-V increased more in the patients with MA. These data demonstrate for the first time that MA is characterized by increased postprandial lipemia in patients with T2DM and may explain in part the excess cardiovascular risk in these patients.

Insulin resistance and other risk factors for coronary heart disease in elderly men. The Study of Men Born in 1913 and 1923.

We have previously shown that insulin is not a major risk factor for CHD. Our data have been re-analysed with longer follow-up and the homeostasis model assessment (HOMA) method. Prospective cohort study of 57- and 67-year-old men. Insulin resistance was estimated with the HOMA equation. Standard methods were used to measure risk factors. The endpoint (CHD) was the combination of non-fatal myocardial infarction and fatal CHD during 13 years of follow-up. The risk of CHD increased 2.5-fold in known diabetics compared with those with normal glucose tolerance, 2.2-fold among those in the highest compared with the lowest quintile of insulin resistance, and 2.4-fold among those in the highest compared with the lowest quintile of fasting insulin. Increased physical activity decreased the risk of CHD by 65%. Cholesterol was also a significant risk factor for CHD but blood pressure, obesity and smoking were not related to the incidence of CHD. Insulin resistance is a significant risk factor for CHD. Whether it is a causal risk factor remains to be proven. Regular physical activity protects against CHD.

The importance of insulin resistance in polycystic ovary syndrome

The most widely accepted criteria for the diagnosis of polycystic ovary syndrome (PCOS) are hyperandrogenism and/or hyperandrogenemia and oligo-ovulation, with the exclusion of other hyperandrogenic disorders (1). Thus, androgen elevation defines the syndrome. This definition permits a wide range of presentations and clinical appearances, that is, a continuum of patients with PCOS. Androgen excess, of ovarian and often also adrenal origin, underlies the symptoms of hirsutism, acne, alopecia, and seborrhea, and treatment with anti-androgens is the most effective method of reducing these complaints. Hyperandrogenemia may also be responsible for the weight gain present in about 50% of cases. What has been increasingly recognized is that PCOS is associated with insulin resistance and compensatory hyperinsulinemia. While not required for the diagnosis of PCOS, insulin resistance appears to cause or exacerbate hyperandrogenemia in many patients, as evidenced by the reduction in ovarian and adrenal androgen levels with insulin-sensitizing therapy (2‐ 6). More importantly, insulin resistance leads to hypertension, diabetes, and cardiovascular disease, the most significant complications of PCOS.

Development of a prediction equation for insulin sensitivity from anthropometry and fasting insulin in prepubertal and early pubertal children.

To test the utility of homeostasis model assessment (HOMA) in predicting insulin sensitivity [x10(- 4) min(-1)/(microIU/ml)] in children and to develop and compare two new prediction equations for insulin sensitivity in children using demographic and anthropometric measures in the presence or absence of fasting insulin. We studied 156 white and African-American children with complete data (mean age 9.7 +/- 1.8 years, 87.8% Tanner Stage 1 or 2). For development of new equations, two-thirds of the children were randomly assigned to a development group, whereas the remaining children were assigned to a cross-validation group. A modified HOMA equation accurately predicted insulin sensitivity, but its utility is similar to fasting insulin alone. Demographic and anthropometric measures alone did not predict insulin sensitivity accurately, even when precise measures of body composition were included in the prediction model. Ethnicity, calf skinfold, and fasting insulin together explained 73% of the variance in insulin sensitivity and accurately predicted insulin sensitivity. The regression of measured versus predicted insulin sensitivity in the cross-validation group was not significantly different from the line of identity (P > 0.05). Mean difference between measured and predicted insulin sensitivity was also not significant (P > 0.05). Some bias was apparent, particularly in white boys. Ethnicity, calf skinfold, and fasting insulin can accurately predict insulin sensitivity with greater precision than HOMA or fasting insulin alone (R(2) = 0.73). Future studies, however, are needed to examine whether a universal equation is possible. A cross-validated prediction equation may be useful in population-based studies when complex measures of insulin sensitivity are not available.

Risk variables of insulin resistance syndrome in African-American and Caucasian young adults with microalbuminuria: the Bogalusa heart study

Microalbuminuria is a strong predictor of cardiovascular disease. Previous studies are inconsistent regarding the relationship between microalbuminuria and insulin resistance syndrome. Therefore, we examined this relationship in 1031 young adults (61% Caucasian, 39% African-American) aged 19 to 32 years. Individuals with either urinary albumin to creatinine ratio at or above the 90th percentile (age, race, and gender specific) or urinary albumin level at or above 30 mg/L were considered as having slightly elevated albumin excretion (microalbuminuria). The multiple risk variables of insulin resistant syndrome measured include body mass index, waist circumference, blood pressure (BP), triglycerides, high-density lipoprotein (HDL) cholesterol, glucose, insulin, insulin resistance index (calculated from a homeostasis model assessment equation), and uric acid. After controlling for age and gender, African-Americans with microalbuminuria by either measure had higher mean systolic ( P < .001) and diastolic ( P < .05) BP, prevalence of hypertension ( P < .05), and, contrary to expectations, HDL cholesterol ( P < .05) than those without this condition. On the other hand, Caucasians showed no such associations. In African-Americans, the above differences in BP levels persisted when hypertensive subjects were excluded. None of the other risk variables displayed any relation to microalbuminuria in both races. These results suggest that microalbuminuria is not necessarily an intrinsic component of the insulin resistance syndrome, at least in the young adult age. Furthermore, the observed association between hypertension and microalbuminuria among young African-Americans may reflect early evidence of renal dysfunction due to the burden of elevated BP in this group.