Body fat distribution and cardiovascular risk in normal weight women. Associations with insulin resistance, lipids and plasma leptin

OBJECTIVE: To systematically examine the correlations between insulin resistance, plasma leptin concentration, obesity and the distribution of fat assessed by anthropometry and magnetic resonance imaging in Asian women. DESIGN: A cross sectional study of non-diabetic, normal weight women. SUBJECTS: Twenty-one healthy women aged 38.8 y (s.d. 11.7) and BMI 22.6 kg/m2 (s.d. 2.3). MEASUREMENTS: Intraperitoneal, retroperitoneal and subcutaneous abdominal fat volume was assessed by magnetic resonance imaging. Anthropometric data were collected. Total fat mass was assessed by bioelectric impedance analysis. Fasting serum lipids, insulin and plasma leptin were assayed. RESULTS: Generalized obesity correlated with subcutaneous abdominal fat mass (r=0.83, P<0.001), but not with intra-abdominal fat mass. Both intraperitoneal fat mass and retroperitoneal fat mass increased with age (r=0.58, P=0.005 and r=0. 612, P=0.003, respectively). Abdominal subcutaneous fat mass was the most important determinant of insulin resistance and plasma leptin. Of the serum lipids, only fasting triglyceride correlated significantly with the waist-to-hip ratio. CONCLUSIONS: It is possible that the large size of the subcutaneous depot compared to the intra-abdominal depot overwhelms any metabolic differences between adipose tissue from these two sites, resulting in the stronger correlation between insulin resistance and subcutaneous abdominal fat mass rather than intra-abdominal fat mass. On the other hand, the distribution of fat between subcutaneous fat depots may be important in the metabolic syndrome given the correlation of fasting triglyceride with waist to hip ratio but not with abdominal fat. However, the study population was small, younger and leaner compared to previous studies and we may not be able to generalize these results to all segments of the population. We confirm that subcutaneous fat mass is the major determinant of plasma leptin.     

Relation between leptin and the metabolic syndrome in elderly women

BACKGROUND: Leptin has been shown to be linked to adiposity and insulin resistance in middle-aged participants. However, the association between leptin and metabolic syndrome independently of body fat and body fat distribution has not been evaluated in healthy elderly people. METHODS: We studied the independent relation between leptin and the components of the metabolic syndrome in 107 women aged 67-78 years with body mass index (BMI) ranging from 18.19 to 36.16 kg/m2. In all participants, we evaluated BMI, waist and hip circumferences, body composition by dual energy X-ray absorptiometry, fasting, and 2-hour glucose, lipids, insulin, homeostasis model assessment of insulin resistance (HOMA), systolic (SBP), diastolic blood pressure (DBP), and leptin. RESULTS: Significant correlation was found between leptin, BMI, waist circumference, fat mass, DBP, SBP, cholesterol, triglycerides, insulin, and HOMA. After adjusting for age and waist circumference, as well for age and fat mass, leptin was significantly related to insulin levels, HOMA, and cholesterol. In a stepwise multiple regression analysis using insulin levels or HOMA as dependent variables and age, waist circumference, fat mass, leptin, SBP, DBP, cholesterol, and triglycerides as independent variables, leptin entered the regression first, waist circumference second, and age third. CONCLUSION: Our study shows that leptin is significantly related to indices of adiposity in elderly women, and leptin is significantly associated with insulin levels, HOMA, and cholesterol independent of age, body fat, and fat distribution. Leptin, waist circumference, and age together explained 31% and 33% of insulin levels and HOMA variance, respectively, in healthy elderly women.     

Serum leptin is associated with serum uric acid concentrations in humans.

This cross-sectional study aimed to evaluate the relationship between leptin and the cluster of abnormalities often referred to as the metabolic syndrome. The serum leptin concentration, body mass index (BMI), percent body fat, total fat mass (FM), waist and hip circumference, waist to hip ratio (WHR), prevalence of hypertension, and triglyceride (TG), lipoprotein, and uric acid concentration were determined in 86 type 2 diabetic (n = 59) and healthy (n = 27) subjects. Multiple regression analyses showed that the estimates of total body obesity (BMI, percent body fat, and total FM), sex, and serum uric acid concentration are independently associated with the serum leptin concentration. The finding of a positive correlation between serum leptin and uric acid levels suggests that leptin could be a pathogenic factor responsible for hyperuricemia in obesity.     

减体重对肥胖和超重者心血管病危险因素的影响

目的：探讨对肥胖和超重者的减肥对心血管危险因素的影响。方法：对41名肥胖和超重者采取6周封闭管理的集中减肥，控制饮食，进行运动训练，每2周测定体重、腰臀围等指标，减肥前、后进行空腹血脂、血糖、血胰岛素、血转氨酶及肝脏超声检查。结果：通过6周减肥，受试者的体重、体重指数、腰围、臀围、腰臀围比、皮褶厚度、体脂含量及百分比、静息血压、心率呈非常明显的下降（P〈0．001）：减肥后血丙氨酸氨基转移酶、甘油三酯、胰岛素及胰岛素抵抗指数明显下降（P〈0．05-〈0．001），血高密度脂蛋白-胆固醇明显升高（P〈0．001），脂肪肝显著改善（P=0．001）。结论：运动锻炼结合饮食控制可减轻肥胖和超重者的体重，有效降低心血管疾病的危险因素。     

Overweight Japanese with body mass indexes of 23.0-24.9 have higher risks for obesity-associated disorders: a comparison of Japanese and Mongolians

OBJECTIVE: The degree of obesity of Asians is less than that of Caucasians. It has been suggested that Japanese, categorized as having normal weight (BMI<25.0), as defined by WHO (2000), have a tendency toward increased incidences of dyslipidemia and diabetes. Our objective was to analyze parameters constituting obesity-associated disorders in overweight Japanese and Mongolians with a body mass index (BMI) of 23.0-24.9, and to assess the suitability for Asians of the Regional Office for Western Pacific Region of WHO criteria pertaining to obesity (WPRO criteria, 2000). DESIGN: Cross-sectional study in a workplace setting. SUBJECTS: A total of 386 Japanese men and 363 Japanese women, and 102 Mongolian men and 155 Mongolian women. MEASUREMENTS: Anthropometric measurements (weight, height, waist circumference, hip circumference and blood pressure) and metabolic measurements (plasma levels of total cholesterol, HDL cholesterol, triglyceride, glucose and insulin). RESULTS: Graded increases in BMI of Japanese and Mongolians were positively associated with body fat percent, waist circumference, hip circumference and waist/hip ratio. The Japanese were categorized as 22% overweight, 22% obese I, 3% obese II; the Mongolians rated as 18% overweight, 34% obese I, 19% obese II, based on the WPRO BMI criteria. The Mongolians had a higher prevalence of obesity and a higher body fat percent, but a lesser gradation of dyslipidemia, than did the BMI-matched Japanese groups. Overweight Japanese (BMI 23.0-24.9), in comparison to normal Japanese (BMI 18.5-22.9), had significant differences in systolic blood pressure, HDL-cholesterol and triglyceride in men, and in systolic and diastolic blood pressure, HDL-cholesterol, triglyceride, insulin and Homoeostasis model assessment-insulin resistance in women. In contrast, the Mongolians showed no significant differences in metabolic parameters between overweight and normal subjects, except for diastolic blood pressure. CONCLUSION: Since the relationship between abdominal fat mass and BMI is ethnic-specific, a universal BMI cutoff point is inappropriate for Asian populations such as the Japanese and Mongolians. The present investigation suggests that, while the WPRO criteria are suitable for Japanese, the WHO criteria are more appropriate for Mongolians.     

低碳水化合物高营养密度膳食对肥胖儿童青少年的减重效果及糖脂代谢的影响

目的探讨低碳水化合物高营养密度膳食对肥胖儿童青少年的减重效果及糖脂代谢的影响。 方法选取2020年6月至2021年6月惠州市中心人民医院肥胖门诊及营养门诊的肥胖儿童青少年（7~18岁）37例作为研究组,选取同期22例肥胖儿童青少年作为对照组,对照组采用平衡膳食及生活方式、运动宣教干预,研究组在生活方式、运动宣教干预的基础上,采用低碳水化合物高营养密度膳食干预,共干预8周,比较两组干预前后BMI、腰臀比、身体成分分析数据以及代谢指标水平。 结果两组患者干预前的BMI、腰围、臀围、腰臀比、体脂率、内脏脂肪面积对比差异均无统计学意义（P>0.05）,在干预8周后,研究组的BMI、腰围、臀围、腰臀比、体脂率和内脏脂肪面积显著低于对照组,差异具有统计学意义（P<0.05）;干预前两组的空腹血糖（FPG）、餐后2 h血糖（2hPG）、空腹胰岛素（FINS）、餐后2 h胰岛素（2hINS）、血尿酸（UA）、血清胆固醇（TC）、甘油三酯（TG）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C）比较差异均无统计学意义（P>0.05）,干预8周后研究组的FPG、2hPG、FINS、2hINS、UA、TC、TG、LDL-C水平均显著低于干预前,且显著低于对照组,差异具有统计学意义（P<0.05）。 结论低碳水化合物高营养密度膳食短期内可以有效使肥胖儿童青少年减重,减少体脂率和内脏脂肪面积,改善其糖脂代谢。     

Effect of weight loss and regional fat distribution on plasma leptin concentration in obese women.

OBJECTIVES: To investigate how circulating leptin concentrations are related to regional fat distribution and whether moderate weight loss alters these relationships. DESIGN: A 6 month, clinical weight reduction trial with measurements before and after weight loss. SUBJECTS: 38 healthy, obese women (age: 44.3+/-9.9 y, BMI: 34.0+/-4.0 kg/m2). MEASUREMENTS: The following measurements were made. 1. indices of obesity and fat distribution: weight, body mass index (BMI), hip circumference (peripheral fat), waist circumference, total body fat (bioelectrical impedance), abdominal fat distribution: visceral fat and abdominal subcutaneous fat (ultrasonography); and 2. Biochemical measurements: plasma leptin and serum insulin. RESULTS: Baseline plasma leptin concentrations were three-fold higher in obese women than in normal weight controls. After weight loss averaging 8.4 kg (9.0%), plasma leptin decreased by a mean of 22.3% (P < 0.001), corresponding to body fat decrease of 16.6% (P < 0.001), abdominal subcutaneous fat decrease of 17.4% (P < 0.001) and visceral fat decrease of 18.7% (P < 0.001). The total amount of body fat correlated with plasma (serum) leptin before (r = 0.64, P < 0.001) and after (r = 0.75, P < 0.001) weight loss. Plasma leptin concentrations expressed per kg of body fat did not change significantly during weight loss. After controlling for body fat, baseline leptin concentrations were significantly associated with hip circumference (r = 0.57, P < 0.001) but not with any indices of abdominal fat distribution. After weight loss the associations became significant for hip and waist circumference as well as for visceral and abdominal subcutaneous fat. Changes in leptin correlated with changes in all indices of obesity except visceral fat. CONCLUSIONS: Plasma leptin concentrations reflect not only total fat mass but also adipose tissue distribution, especially peripheral fat. Plasma leptin values per kilogram of fat mass do not change significantly with modest weight loss.     

空腹血糖正常者非酒精性脂肪肝危险因素探讨

目的　探讨空腹血糖正常的非酒精性脂肪肝 (简称脂肪肝 )形成的危险因素。方法　引用 2 0 0 3- 11-0 1～ 2 0 0 3- 11- 30深圳某区探访病调查资料中空腹血糖 <5 . 6mmol/L的脂肪肝患者 15 8例和正常对照 316名参加本研究 ,采用McAuley指数、稳态模式法胰岛素抵抗指数 (HOMA -IR)和空腹胰岛素 (FINS)评价胰岛素抵抗。结果　控制年龄和性别后与对照组比较 ,脂肪肝组体重指数、腰围、腰臀比、全身脂肪百分比、收缩压、舒张压、总胆固醇、低密度脂蛋白胆固醇、甘油三酯、HOMA -IR和FINS升高 (均为P <0 . 0 0 1) ,而高密度脂蛋白胆固醇和McAuley指数降低 (均为P <0 .0 0 1) ;Logistic回归分析显示 ,体重指数、腰围和McAuley指数是脂肪肝形成的独立危险因素。结论　空腹血糖正常者脂肪肝形成的独立危险因素是肥胖和胰岛素抵抗。     

Adipocytokines, fat distribution, and insulin resistance in elderly men and women

BACKGROUND: The aim of this study was to evaluate the relation between adiponectin and leptin, fat distribution, and insulin resistance in elderly men and women. METHODS: 68 elderly participants (28 men and 40 women) aged 66-77 years, with body mass index (BMI) ranging from 19.83 to 37.18 kg/m2, participated in the study. In all participants, we evaluated BMI, waist and hip circumferences, sagittal abdominal diameter (SAD), fat mass (FM) by dual energy X-ray absorptiometry, fasting and 2-hour glucose, insulin, homeostasis model assessment of insulin resistance (HOMA), leptin, and adiponectin. RESULTS: Elderly women had significantly higher circulating levels of adiponectin and leptin compared to men even after adjusting for age, FM, or waist circumference. In men and women, leptin was positively associated, whereas adiponectin was negatively associated, with BMI, indices of body fat distribution, as well as FM and FM%. Both fasting insulin and HOMA showed significant positive correlation with leptin and negative correlation with adiponectin in both sexes. In a step-wise multiple regression model with HOMA as the dependent variable and age, gender, waist circumference, FM, leptin, and adiponectin as independent variables, waist entered the regression first, explaining 19.7% of HOMA variance, leptin was second, and adiponectin was third, explaining each one an additional 10% of variance. In a multiple linear regression analysis, leptin and adiponectin alone explained up to 38% of HOMA variance. CONCLUSION: Leptin and adiponectin together seem to be strictly related to insulin resistance in elderly people, independently of body fat and body fat distribution.     

Association of waist circumference with ApoB to ApoAI ratio in black and white Americans.

BACKGROUND: Although numerous studies have demonstrated obesity as an aspect of the insulin resistance syndrome in cardiovascular disease (CVD), the mechanism is not clear. Central adiposity, acting through many CVD risk factors, including, plasma glucose, insulin, total cholesterol, low density lipoprotein-cholesterol (LDL-C) and lipoprotein moities-apolipoprotein B (ApoB), apolipoprotein A-I (ApoAI), by atherogenic and thrombotic mechanisms has been proposed as a possible mechanism. In this study, we examined the relationship between central fat distribution (defined by waist circumference) and the ratio of these lipoproteins (ApoB/ApoAI). SUBJECTS AND METHODS: Association between ApoB/ApoAI ratio and waist circumference was compared in Blacks (n = 854) and Whites (n = 2552) using the NHANES III population-based samples. Correlation analyses and multiple regression analyses were used to determine the association between ApoB/ApoAI and waist circumference, controlling for age, body mass index (BMI), race, gender, plasma glucose, insulin, serum triglyceride and total cholesterol. RESULTS: Adjusting for age, ApoB/ApoAI was significantly correlated with waist circumference (Black men: r = 0.38, White men: r = 0.26, Black women: r = 0.20, White women: r = 0.36) (all P < 0.01). Adjusting for age and triglyceride or insulin, waist circumference was also positively correlated with CVD risk factors including, ApoB, LDL-C, plasma glucose and fasting insulin, and inversely correlated with ApoAI and HDL-C in Blacks and Whites (P < 0.05). Overall, triglyceride and total cholesterol were the strongest predictors of ApoB/ApoAI in Blacks and Whites adjusting for age, BMI and insulin, than waist girth (P < 0.01). CONCLUSIONS: The result of this study suggests the need to investigate ApoB/ApoAI as another possible facet in the insulin resistant syndrome.     

Urinary epinephrine and norepinephrine interrelations with obesity, insulin, and the metabolic syndrome in Hong Kong Chinese

The metabolic syndrome is characterized by a clustering of cardiovascular risk factors including type 2 diabetes mellitus, hypertension, dyslipidemia, and obesity. Elevated plasma insulin and urinary norepinephrine (noradrenaline) and reduced urinary epinephrine (adrenaline) excretion are associated with obesity in Caucasian populations. We examined the interrelationships between obesity, plasma insulin, and urinary catecholamine excretion in Chinese subjects with various components of the metabolic syndrome. A total of 577 Chinese subjects (aged 38 +/- 10 years; 68% with type 2 diabetes mellitus, hypertension, dyslipidemia, obesity, and/or albuminuria and 32% healthy subjects) were studied, all of whom had a plasma creatinine less than 150 micromol/L. The blood pressure, height, weight, waist and hip circumference, and fasting plasma glucose, insulin, lipid, and creatinine levels were measured. A 24-hour urine sample was collected for measurement of albumin and catecholamine excretion. The body mass index (BMI) and waist circumference were used as measures of general and central obesity, respectively. The insulin resistance index was estimated by the calculated product of fasting plasma insulin and glucose concentrations. Patients with an increasing number of components of the metabolic syndrome (type 2 diabetes mellitus, hypertension, dyslipidemia, obesity, and/or albuminuria) were more obese, hyperglycemic, dyslipidemic, and albuminuric and had higher blood pressure, plasma insulin, insulin resistance indices, and 24-hour urinary norepinephrine excretion but lower urinary epinephrine output (all P < .005). Increasing quintiles of BMI in the whole population or waist circumference in both sexes were associated with increasing trends for adverse lipid profiles, plasma insulin, insulin resistance indices, and urinary norepinephrine excretion but a decreasing trend for urinary epinephrine output (all P < .001). There were close associations between age, obesity, blood pressure, fasting plasma glucose, lipid, insulin, insulin resistance indices, and urinary catecholamine excretion. Using stepwise multiple regression analysis (all P < .001), 34% of the variability of the BMI and 45% of that of the waist circumference were independently related to gender (waist higher in males and BMI higher in females), increased plasma insulin, triglyceride, and urinary norepinephrine excretion, and decreased high-density lipoprotein (HDL) cholesterol and urinary epinephrine output. In Chinese subjects with different manifestations of the metabolic syndrome, hyperinsulinemia, insulin resistance, elevated norepinephrine, and reduced epinephrine excretion were closely associated with general and central obesity. Based on these findings, we postulate that complex interactions between the insulin and sympathoadrenal systems may lead to the development of obesity and the metabolic syndrome.     

Relationships between fasting plasma ghrelin levels and metabolic parameters in children and adolescents

Recent findings suggest that ghrelin may have a beneficial effect on vasculature. In the present study, we examined the associations between plasma ghrelin concentration and metabolic parameters in children and adolescents. We measured fasting plasma ghrelin concentrations in 50 Korean children and adolescents (28 boys and 22 girls, mean +/- SD age 12.6 +/- 2.7 years, body mass index 22.7 +/- 5.1 kg/m 2 ), and analyzed the associations between fasting plasma ghrelin level and anthropometric measurements, metabolic parameters, leptin concentration, and fasting insulin level. We found that fasting plasma ghrelin concentration was negatively correlated with height, weight, body mass index, percent body fat, waist circumference, and hip circumference in both boys and girls. Fasting plasma ghrelin levels were significantly negatively correlated with triglycerides and fasting insulin levels and positively correlated with high-density lipoprotein cholesterol in boys, but not in girls. Our results thus demonstrate that higher plasma ghrelin levels have beneficial effects on metabolic parameters in boys and that the relationships between fasting plasma ghrelin levels and metabolic parameters differed according to sex.     

Relationships between plasma adiponectin and body fat distribution, insulin sensitivity, and plasma lipoproteins in Alaskan Yup'ik Eskimos: the Center for Alaska Native Health Research study

Adiponectin, a protein secreted by adipose tissue, has antiatherogenic, anti-inflammatory, and insulin-sensitizing actions. We examined the relationship between plasma adiponectin and adiposity, insulin resistance, plasma lipids, glucose, leptin, and anthropometric measurements in 316 adult men and 353 adult women Yup'ik Eskimos in Southwest Alaska. Adiponectin concentration was negatively associated with body mass index, percentage of body fat, sum of skin folds, waist circumference, triglycerides, insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]), fasting insulin, and leptin in both men and women, and also with glucose in women. Adiponectin concentration correlated positively with high-density lipoprotein cholesterol concentration, and also with low-density lipoprotein cholesterol in women. Insulin-sensitive individuals (HOMA-IR <3.52, n = 442) had higher plasma adiponectin concentrations than more insulin-resistant individuals (HOMA-IR ≥3.52, n = 224): 11.02 ± 0.27 μg/mL vs 8.26 ± 0.32 μg/mL, P < .001. Adiponectin concentrations did not differ between groups of participants with low and high level of risk for developing coronary heart disease. No difference in plasma adiponectin levels was found among Yup'ik Eskimos and whites matched for sex, age, and body mass index. In conclusion, circulating adiponectin concentrations were most strongly associated with sum of skin folds in Yup'ik men and with high-density lipoprotein cholesterol levels, sum of skin folds, waist circumference, and insulin and triglycerides concentrations in Yup'ik women.     

Difficulty in losing weight by behavioral intervention for women with Trp64Arg polymorphism of the beta3-adrenergic receptor gene

OBJECTIVE: Trp64Arg mutation in the beta(3)-adrenergic receptor (beta(3)AR) gene is relatively common in Japanese people. However, it has not been clear whether persons with Trp64Arg mutation in the beta(3)AR gene tend to have obesity and difficulty in losing weight even with a restricted diet and exercise. We investigated the response of body weight and metabolic factors to behavioral intervention in Japanese women with Trp64Arg mutation in the beta(3)AR gene. DESIGN: A 3-month behavioral intervention study using a combination of diet and exercise programs. SUBJECTS: A total of 76 perimenopausal women with no clinical symptoms (age: 54.7+/-7.7 y, body mass index (BMI): 21.0-33.0 kg/m(2)). MEASUREMENTS: Anthropometric measurements (weight, height, body fat, waist circumference, hip circumference, skin fold, resting energy expenditure and blood pressure) and metabolic measurements (serum levels of cholesterol, triglyceride, phospholipid, nonesterified fatty acid, glucose, insulin and leptin) and determination of the beta(3)AR genotype by polymerase chain reaction followed by BstNI digestion. RESULTS: At the baseline of BMI, body weight, body fat, waist circumference, hip circumference, the arm skin fold, resting energy expenditure, or blood lipid and glucose profiles, there was no significant difference in participants with/without mutation of the beta(3)AR gene. The intervention yielded a body weight reduction in 69 and 48%, and induced a significant difference in weight loss (-0.74 and -0.01 kg) for women with wild-type and Trp64Arg mutation, respectively. Significant differences of anthropometric parameters were found in body weight, BMI, waist and hip circumferences and blood pressure of wild type by the intervention. However, women with Trp64Arg mutation did not show significant changes in these anthropometric parameters, except for hip circumference. A significant difference was found in high-density lipoprotein cholesterol (HDL-C) and in the low-density lipoprotein cholesterol/HDL-C ratio in both genotypes. CONCLUSION: The results of the present study suggest that the Trp64Arg mutation of the beta(3)AR gene is associated with difficulty in losing weight through behavioral intervention, although it is not related to obesity-related phenotypes and resting energy expenditure before the intervention.     

High prevalence of insulin resistance in postpubertal Asian Indian children is associated with adverse truncal body fat patterning, abdominal adiposity and excess body fat

OBJECTIVE: The objectives were to study the relationships of insulin resistance with generalized and abdominal obesity, and body fat patterning in urban postpubertal Asian Indian children. DESIGN: Cross-sectional, population-based epidemiological study. SUBJECTS: In all, 250 (155 males and 95 females) healthy urban postpubertal children. MEASUREMENTS: Anthropometric profile, percentage of body fat (%BF), fasting serum insulin, and lipoprotein profile. RESULTS: Fasting insulin correlated significantly with body mass index (BMI), %BF, waist circumference (WC), central and peripheral skinfold thicknesses and sum of four skinfold thicknesses (Sigma 4SF) in both sexes, and with systolic blood pressure and waist-to hip circumference ratio (W-HR) in males only. Consistent increase in fasting insulin was noted with increasing values of central skinfold thickness at each tertile of peripheral skinfold thickness, WC, and %BF. Central skinfold thickness correlated with fasting insulin even after adjusting for WC, W-HR, and %BF. The odds ratios (OR) (95% CI) of hyperinsulinemia (fasting insulin concentrations in the highest quartile) were 4.7 (2.4-9.4) in overweight subjects, 8 (4.1-15.5) with high %BF, 6.4 (3.2-12.9) with high WC, 3.7 (1.9-7.3) with high W-HR, 6.8 (3.3-13.9) with high triceps skinfold thickness, 8 (4.1-15.7) with high subscapular skinfold thickness, and 10.1 (5-20.5) with high Sigma 4SF. In step-wise multiple logistic regression analysis, %BF [OR (95% CI): 3.2 (1.4-7.8)] and Sigma 4SF [OR (95% CI): 4.5 (1.8-11.3)] were independent predictors of hyperinsulinemia, similar to insulin resistance assessed by HOMA (homeostatic model of assessment) in the study. CONCLUSION: A high prevalence of insulin resistance in postpubertal urban Asian Indian children was associated with excess body fat, abdominal adiposity, and excess truncal subcutaneous fat. Primary prevention strategies for coronary heart disease and diabetes mellitus in Asian Indians should focus on the abnormal body composition profile in childhood.     

Leptin concentrations in relation to overall adiposity, fat distribution, and blood pressure in a rural Chinese population

OBJECTIVE: To examine the associations between leptin levels and body mass index (BMI), fat distribution (reflected by waist to hip ratio and skinfold measurements), and blood pressure in a rural Chinese population. DESIGN AND SUBJECTS: A cross-sectional study of 294 participants who provided blood samples. MEASUREMENTS: Plasma concentrations of leptin, BMI, waist to hip ratio, skinfold thickness, and blood pressure. RESULTS: The average leptin concentration was 5.2 microg/l (3.1 for men and 7.3 for women). In univariate analyses, leptin levels were significantly correlated with BMI (r=0.47), abdominal skinfold thickness (r=0.53), triceps skinfold thickness (r=0.56), waist circumference (r=0.41), hip circumference (r=0.51), waist to hip ratio (r=0.17), and diastolic blood pressure (r=0.13). In multivariate analyses controlling for age, sex, education, current smoking, and alcohol use, independent associations between leptin levels and BMI, waist to hip ratio, waist circumference, and abdominal skinfold thickness remained. However, the significant association between leptin and blood pressure disappeared after adjusting for BMI, whereas the association between BMI and blood pressure persisted after adjusting for leptin level. CONCLUSIONS: We observed a strong positive relationship between overall adiposity and leptin levels in both men and women in a rural Chinese population. In addition, leptin concentrations were significantly associated with central obesity measured by waist to hip ratio and abdominal skinfold, independent of overall obesity. The observed positive association between leptin and blood pressure was largely explained by BMI. International Journal of Obesity (2001) 25, 121-125     

Renal function and insulin resistance as determinants of plasma leptin levels in patients with NIDDM

Summary Plasma leptin level is known to correlate with the degree of obesity. To determine the influences of renal fuction and insulin resistance on plasma leptin concentrations, we measured plasma leptin concentrations and performed the euglycaemic hyperinsulinaemic clamp studies in 57 patients with non-insulin-dependent diabetes mellitus with a wide range of renal function. In simple regression analyses, plasma leptin concentration showed significant positive correlations with percentage of body fat measured by dual energy X-ray absorptiometry, body mass index, waist to hip ratio and fasting plasma insulin. Leptin level was higher in females than males. Multiple regression analyses indicated that percent body fat, waist to hip ratio, plasma insulin, gender and renal function (1/creatinine), but not insulin sensitivity, were significant and independent determinants of plasma leptin level. These results suggest that plasma leptin level is regulated or affected by multiple factors including renal function. Insulin resistance appeared to increase leptin levels indirectly by raising plasma insulin. [Diabetologia (1997) 40: 676–679] Received: 27 November 1996 and in revised form: 3 March 1997     

Plasma leptin is associated with insulin resistance independent of age, body mass index, fat mass, lipids, and pubertal development in nondiabetic adolescents

OBJECTIVE: The rising epidemic worldwide in overweight and obese children requires urgent attention. Leptin has been found to be associated with body weight control and possibly affects insulin sensitivity. Since insulin resistance is associated with obesity in adults and possibly in adolescents, we set out to investigate the association of plasma leptin level with various anthropometric indices, body fat mass (FM), lipids, and insulin resistance (IR) index in nondiabetic adolescents. DESIGN: A cross-sectional study from three high schools in Taipei City in Taiwan. SUBJECTS: A total of 402 nondiabetic subjects (162 boys and 240 girls; age range, 10-19 y; mean age, 15.8+/-1.9 y, and mean body mass index (BMI), 24.8+/-4.6 kg/m(2)) were recruited. MEASUREMENTS: The fasting plasma leptin, plasma glucose, insulin, lipids, and anthropometric indices including height, weight, waist (WC) and hip circumferences, and waist-to-hip ratio (WHR) were examined. Total body FM and percentage body fat (FM%) were obtained from dual-energy X-ray absorptiometry. The homeostasis model was applied to estimate the degree of IR. RESULTS: The plasma leptin levels were significantly higher in girls (17.45+/-10.13 ng/ml) than boys (8.81+/-6.71 ng/ml, P<0.001). The plasma leptin levels were positively correlated to BMI, WC, WHR, FM, FM%, and triglycerides (TG). The IR index was positively correlated to BMI, WC, WHR, FM, FM%, TG, and leptin. Using the multivariate linear regression models, we found that plasma leptin remains significantly associated with IR index even after adjusting for age, gender, BMI, FM, WC, Tanner stage, and TG. CONCLUSION: Plasma leptin was associated with IR index independent of age, gender, BMI, FM, WC, Tanner stage, and TG. Plasma leptin levels in adolescents could be a predictor for the development of the metabolic syndrome disorders and cardiovascular diseases.     

Leptin interacts with heart rate but not sympathetic nerve traffic in healthy male subjects

OBJECTIVE: Administration of leptin to animals increases sympathetic nerve activity and heart rate. We therefore tested the hypothesis that plasma leptin is linked independently to muscle sympathetic nerve activity (MSNA) and heart rate in healthy humans. METHODS: We measured plasma leptin, plasma insulin, body mass index (BMI), percent body fat, waist: hip ratio, MSNA, heart rate and blood pressure in 88 healthy individuals (50 men and 38 women). RESULTS: In men, plasma leptin concentration correlated significantly with BMI (r = 0.75, P < 0.001), percent body fat (r = 0.70, P< 0.001), waist: hip ratio (r = 0.69, P < 0.001), insulin (r = 0.37, P = 0.009), and age (r = 0.38, P = 0.006). Only BMI and waist: hip ratio were linked independently to plasma leptin concentration (r = 0.78, P < 0.001). Plasma leptin concentrations also correlated with heart rate (r = 0.39, P = 0.006) and mean arterial pressure (MAP; r = 0.38, P = 0.007), but not with MSNA (r = 0.17, P = 0.24). After adjustment for BMI and waist: hip ratio, plasma leptin concentration correlated significantly only with heart rate (r = 0.29, P = 0.04), and not with MAP (r = 0.21, P = 0.14). Individuals were divided into high-leptin and low-leptin subgroups on the basis of plasma leptin concentrations adjusted for BMI and waist: hip ratio. Those with high leptin concentrations had significantly faster heart rates than those with low leptin. MAP and MSNA were similar in both subgroups. No relationship between leptin and either heart rate or MSNA was evident in women. CONCLUSIONS: In normal men, heart rate, but not MSNA, is linked to plasma leptin concentration. This sex-specific relationship between heart rate and plasma leptin is independent of plasma insulin, BMI, waist:hip ratio and percentage body fat.     

Insulin sensitivity and secretion influence the relationship between growth hormone-binding-protein and leptin

BACKGROUND: A direct relationship between body mass index (BMI), visceral adipose tissue, insulin levels and growth hormone-binding protein (GHBP) activity has consistently been reported. It was recently described that GHBP directly depends on serum leptin levels. Since leptin co-varies with insulin secretion and/or sensitivity, we aimed to study the influence of these variables on plasma GHBP activity. SUBJECTS: In order to isolate the effects of obesity per se from those of insulin secretion, three groups of subjects were prospectively studied: 14 lean, 10 obese and nine obese subjects with glucose intolerance. MEASUREMENTS: The percentage of body fat was measured through bioelectric impedance. Insulin sensitivity and secretion were determined through a frequently sampled intravenous glucose tolerance test with minimal model analysis. Serum leptin was measured by radioimmunoassay. GHBP activity was determined by the high performance liquid chromatography-gel filtration method. RESULTS: Plasma GHBP activity was found to correlate with BMI (r = 0. 65, P < 0.0001), fat mass (r = 0.51, P = 0.003), waist circumference (r = 0.64, P < 0.0001), waist-to-hip ratio (r = 0.42, P = 0.01), insulin sensitivity (SI, r = - 0.61, P = 0.0001), insulin secretion (expressed as the acute insulin response to intravenous glucose, AIRg) (r = 0.48, P = 0.006) and leptin concentration (r = 0.49, P = 0.004). The associations with SI (r = - 0.42, P = 0.02) and AIRg (r = 0.38, P = 0.03) persisted even after controlling for fat mass. Since insulin secretion and insulin sensitivity usually covary in glucose tolerant subjects (an increased insulin secretion is necessary to compensate a decreased insulin sensitivity), we constructed a multiple linear regression to predict GHBP activity. In this model, SI (P = 0.005), AIRg (P = 0.02) and SD score-leptin (P = 0.03) independently contributed to 34, 10 and 8% of the variability in serum GHBP activity. CONCLUSIONS: Our results suggest that plasma GHBP activity is simultaneouslly influenced by insulin secretion and sensitivity and leptin. Perhaps leptin, through increased insulin secretion, might induce GHBP/GH secretion, explaining the normal to high insulin-like growth factor (IGF)-I levels found in overnutrition.