Insulin and HOMA in Spanish prepubertal children: relationship with lipid profile

OBJECTIVE: The effects of insulin or insulin resistance on the lipid profile seem to change with age. The aim of this study was to analyze insulin levels and an insulin resistance index and to investigate the relationship between these and the lipid profile in a population-based sample of Spanish prepubertal children. METHODS: 1048 (524 boys and 524 girls) randomly selected prepubertal children were studied. Children were 6 to 8 years old with a mean age of 6.7. Plasma lipid, FFA and insulin levels were measured. The homeostatic model assessment (HOMA) was calculated as an indicator of insulin resistance. RESULTS: When analyzing percentile values of insulin, HOMA and FFA by sex, we observed that girls had significantly higher insulin concentrations than boys (except at the 10th percentile) and significantly higher FFA (except at the 90th percentile) with no significant differences between sexes for HOMA. Multivariate regression analyses showed that insulin was positively associated with glucose, triglycerides and apoB in boys but not in girls, and negatively associated with FFA in both genders. CONCLUSIONS: We report here data about the distribution of insulin in the Spanish prepubertal population. The higher levels of insulin in prepubertal girls could indicate that girls start to be more insulin resistant than boys at this age, although other manifestations of insulin resistance are not yet detectable.     

Sex-related differences between adiponectin and insulin resistance in schoolchildren

OBJECTIVE: To study the effect of body composition and adiponectin on insulin resistance and beta-cell function in schoolchildren during puberty. RESEARCH DESIGN AND METHODS: Plasma adiponectin level and its relationships with insulin sensitivity and beta-cell function were analyzed in 500 randomly recruited nondiabetic Taiwanese schoolchildren (245 boys and 255 girls) aged 6-18 years in a national survey program for diabetes in 1999. Insulin resistance and beta-cell function were evaluated by homeostasis model assessment (HOMA). Plasma adiponectin concentrations were determined with radioimmunoassay. RESULTS: Plasma glucose levels remained stable, whereas insulin resistance increased with a compensatory rise in beta-cell function during this period. A transient drop of adiponectin level with a trough at 10-12 years was found in boys but not in girls. This pubertal drop of adiponectin levels in boys coincides with the sharp rise in testosterone concentration. A negative correlation between testosterone levels and adiponectin concentration was also noted in boys (r = -0.142, P = 0.032). Plasma adiponectin levels correlated inversely with relative body weight, fasting insulin concentrations, and insulin resistance index by HOMA in boys aged 15-18 years and in girls aged 11-14 years. No association was observed between adiponectin levels and beta-cell function by HOMA. CONCLUSIONS: There is a transient drop in the level of adiponectin during male puberty, correlated with the increase in testosterone level in boys. Plasma adiponectin levels were inversely correlated with obesity and insulin resistance in boys and girls during the pubertal period.     

Obesity, plasma high sensitivity C-reactive protein levels and insulin resistance status among school children in Taiwan

OBJECTIVE: To evaluate the degree of obesity and plasma high sensitivity C-reactive protein (hs-CRP) levels in relation to insulin resistance status among school children in Taiwan. METHODS: After multistage sampling, we randomly selected 1438 children (701 boys and 737 girls) with the mean age of 13.4 years (from 12 to 16) in Taipei in 2003. Anthropometric measures and plasma biochemical variables (including lipid profiles, glucose and insulin) were measured using standard methods. Plasma hs-CRP levels were measured using nephelometric methods. We calculated insulin resistance (IR) index using HOMA methods and further calculated a gender-specific insulin resistance syndrome (IRS) summary score by adding the quartile ranks from the distribution of systolic blood pressure (SBP), triglyceride (TG), high density lipoprotein-cholesterol (HDL-C) and insulin levels of each children. A high IRS summary score corresponds to higher levels of SBP, TG and insulin levels and lower levels of HDL-C. RESULTS: Boys were taller, heavier, had larger BMI, glucose, IRS summary score and hs-CRP than girls; however, there is no difference in plasma TG, insulin levels, and IR index between genders. Plasma hs-CRP levels were positively correlated with anthropometric measures, TG, insulin levels, IR index, and IRS summary score and negatively correlated with HDL-C. Anthropometric measures, plasma TG, insulin levels, IR index and IRS summary score were significantly higher in children with higher plasma hs-CRP levels (test for trend p<0.05). After adjustment for age, heart rate, smoking and drinking, hs-CRP continued to be positively associated with anthropometric variables (weight and BMI), insulin levels, and IR index and negatively correlated with HDL-C in both genders. Plasma hs-CRP levels were also positively associated with TG and IRS summary score in boys and glucose in girls. However, after further adjusting for BMI, the association of hs-CRP on TG, insulin levels, IR index and IRS summary score disappeared in boys and on body weight, HDL-C, insulin level and IR index disappeared in girls. CONCLUSION: Plasma hs-CRP levels are positively related to anthropometric variables, such as body weight and BMI, insulin levels, IR index and IRS summary score and negatively related to HDL-C in Taiwanese children. Moreover, the degree of body fat status (as measured by BMI) plays a more significantly role on insulin resistance status than hs-CRP levels among Taiwanese children.     

Correlation of plasma leptin and adiponectin with insulin sensitivity and beta-cell function in children - the Taipei Children Heart Study

To investigate the association between plasma leptin and adiponectin and insulin sensitivity in children, 580 school children (294 boys and 286 girls) with mean age of 13.3 years (12-16 years) were randomly selected from the Taipei Children Heart Study. Baseline measurements included body weight, body mass index (BMI), plasma glucose, insulin, proinsulin, leptin and adiponectin levels. Insulin resistance and beta-cell function were assessed using the method of homeostatic model, HOMA-IR and HOMA-beta, respectively. We found that girls had higher levels of plasma leptin, adiponectin and HOMA-beta than boys. There was no significant difference in HOMA-IR between boys and girls. Plasma leptin concentrations were positively correlated with body weight, BMI, insulin and proinsulin concentrations, HOMA-IR and HOMA-beta, whereas plasma adiponectin levels were inversely associated with body weight, BMI and proinsulin levels in both sexes. In girls, adiponectin concentrations were negatively correlated with insulin concentration and HOMA-IR. In multiple regression analyses, plasma leptin was more positively associated with insulin and proinsulin levels, HOMA-IR and HOMA-beta than was adiponectin in boys. This association persisted even after adjusting for body weight, BMI and pubertal status. In conclusion, plasma leptin was more strongly associated with insulin sensitivity and beta-cell function than was adiponectin among children, particularly in boys.     

Insulin,proinsulin and insulin resistance status in relation to lipid profiles among school children in Taiwan-The Taipei Children Heart Study

PURPOSE: Evidence suggests that there may be a metabolic syndrome characterized by hyperinsulinemia or insulin resistance associated with increased cardiovascular disease risk. The purpose of this study is to evaluate insulin, proinsulin or insulin resistance to determine which is the best parameter to predict lipid profiles among children in Taiwan. METHODS: After multi-stage sampling, we randomly included 852 school children (415 boys and 437 girls) with a mean age of 13 yr in this study. We measured insulin and intact proinsulin levels by RIA (<0.2% cross-reactivity) and estimated insulin resistance index (IRI) using the homeostatic model assessment (HOMA) method. We used standard methods to measure atherosclerotic lipid profiles including total cholesterol (CHOL), triglyceride (TG), HDL-C, apolipoprotein A (ApoA), apolipoprotein B (ApoB), and lipoprotein[a] and calculated LDL-C and TCHR (total cholesterol to HDL-C ratio) levels. RESULTS: Girls had higher CHOL, LDL-C, ApoA and ApoB levels than boys (p < 0.001). There was no significant difference in insulin, proinsulin and IRI status between boys and girls. Among boys, insulin, proinsulin and IRI were positively correlated with TG, ApoB and TCHR and negatively related to HDL-C. Among girls, these associations were attenuated and became insignificantly for TCHR and HDL-C. After adjusting for potential confounders, IRI and insulin were still positively associated with TG and ApoB levels and negatively associated with HDL-C in boys. However, in girls, proinsulin and insulin were positively associated with TG only. Finally, in the stepwise regression analyses, IRI was a better predictor of TG, HDL-C, and ApoB than insulin or proinsulin in boys. However, in girls, proinsulin was a stronger predictor than insulin or IRI for TG and TCHR. CONCLUSION: From this study, we found that IRI (in boys) and proinsulin (in girls) levels are generally more significant and stronger parameters than insulin for predicting lipid profiles among children in Taiwan.     

Reference intervals for testosterone, androstenedione and SHBG levels in healthy females and males from birth until old age

The measurement of androgen levels is important in the follow-up of sexual development and in the diagnosis of disturbances of the gonadal function in children and adults. The aim of this study was to evaluate the age dependence of the serum concentrations of testosterone, androstenedione, and SHBG from birth until old age using the IMMULITE 2000 automated assay system (DPC, Los Angeles). Testosterone and androstenedione median levels were very high during the first weeks of life due to residual maternal hCG and decreased to low basal levels around the detection limit of the assay. With the onset of puberty around the age of 10 years both parameters increased strongly, reaching a maximum at about 17 years (testosterone: > 20-fold in boys, 2-fold in girls; androstenedione: 10-fold in boys, 5-fold in girls). In both girls and boys, we measured a decline in the SHBG medians during sexual maturation. This decline was more pronounced in boys (median 78.3 to 26.2 nmol/l from Tanner stage 1 to 5) since the higher androgen levels are thought to down-regulate SHBG. In male adults a continuous decrease was seen for testosterone from a median of 16.1 nmol/l in age group 21-30 years to 9.7 nmol/l in the age group > 70 years. In women the testosterone levels which were only about 5% of that of men from the same age group decreased only slightly, starting from a median of 0.9 to 0.6 nmol/l. In both sexes androstenedione levels decreased continuously during aging. In contrast to the androgen levels, the median SHBG levels increased steadily in men from 20.8 to 44.5 nmol/l, while the median SHBG levels in women decreased from 78.3 to 44.5 nmol/l in the age group of 61-70 years. Interestingly, the SHBG levels rose again in women of the group > 70 years. The reference intervals elaborated here may help in the assessment of the status of sexual development, and to diagnose pathologies of the gonadal axis or hypogonadism during aging.     

Relation of C-reactive protein to insulin resistance and cardiovascular risk factors in youth

OBJECTIVE: Insulin resistance and C-reactive protein (CRP) levels are strongly correlated in adults. This study explored the relationship in youth. RESEARCH DESIGN AND METHODS: Associations between CRP levels, cardiovascular risk, and insulin resistance measured by the euglycemic clamp were investigated in 342 healthy Minneapolis youth. RESULTS: There was no difference in mean CRP levels among boys (n = 189, CRP 1.10 +/- 0.46 mg/l) and girls (n = 153, CRP 1.16 +/- 0.63 mg/l; P = 0.32). There was also no difference between CRP and Tanner stage. CRP, adjusted for BMI, was significantly greater in black subjects compared with white subjects (P = 0.03). CRP was strongly related to adiposity in both girls and boys. CRP levels were related to fasting insulin levels (r = 0.16, P = 0.003) but this association was not significant after adjustment for BMI (r = 0.07, P = 0.21). Similarly, M, the euglycemic clamp measurement of insulin sensitivity, was significantly related to CRP levels (r = -0.13, P = 0.02) but not when M was normalized to lean body mass (M(lbm)) (r = -0.10, P = 0.09). There was a significant inverse correlation between M(lbm) and CRP quartiles, which disappeared after adjustment for BMI. There was no significant association between CRP levels and lipids, blood pressure, physical activity, or left ventricular mass. CONCLUSIONS: In contrast to adult subjects, after adjustment for adiposity, CRP levels in children age 10-16 years were not significantly associated with insulin resistance or with other factors comprising the metabolic syndrome. This is consistent with the concept that insulin resistance may precede the development of CRP elevation in the evolution of the metabolic syndrome.     

Prevalence and risk factors of metabolic syndrome in Brazilian and Italian obese adolescents: a comparison study

Background: Metabolic syndrome (MS) prevalence between different populations in obese adolescents is scanty to date. Objective: To compare the MS prevalence and related risk factors in Brazilian and Italian obese adolescents. Methods: A total of 509 adolescents (110 Brazilian, 399 Italian), aged 15–19 years. Anthropometric characteristics, triglycerides (TG), total, low‐density lipoprotein (LDL)‐, high‐density lipoprotein (HDL)‐cholesterol, fasting plasma glucose (FPG), insulin, homeostasis model assessment of insulin resistance (HOMA‐IR) and blood pressure were measured. Results: Age, body mass index (BMI) and BMI z‐score were not significantly different between the two subgroups. BMI z‐score, TG, FPG, HOMA‐IR and systolic blood pressure (SBP) were significantly higher in boys than in girls both in Brazilian and Italian adolescents, while HDL‐cholesterol levels were lower in boys than in girls. No significant differences were observed in BMI, LDL and total‐cholesterol and DBP in two genders and groups. Insulin, FPG, HOMA‐IR and TG were significantly higher, while LDL‐cholesterol and SBP were significantly lower in Brazilian than in Italian subjects, both in males and females. HDL and total‐cholesterol and diastolic blood pressure (DBP) were not significantly different between the two subgroups and genders. MS prevalence was higher in Brazilian than in Italian obese boys (34.8 vs. 23.6%, p < 0.001) and girls (15.6 vs. 12.5%, p < 0.01). The most frequently altered parameter was HOMA‐IR both in subjects with MS (100% in Brazilian and 81.8% in Italian) and without MS (42.9% and 11.7%). Conclusion: Metabolic syndrome represents a worldwide emerging health problem in different ethnical populations, the alterations of the risk factors related to MS (different in their prevalence between different subgroups) being strictly linked to the degree of obesity.     

Plasma TNF-R1 and insulin concentrations in relation to leptin levels among normal and overweight children

OBJECTIVES: Leptin is a multifunctional polypeptide produced primarily by adipocytes and associated with the occurrence of obesity and insulin resistance. Tumor necrosis factor-alpha (TNF-alpha), a polypeptide cytokine produced primarily by mononuclear phagocytes, plays a key role in the initiation of the inflammatory response but has a multitude of effects in many tissues. The interactions between TNF-alpha and insulin on leptin expression are complicated and have not been completely described. The purpose of this study is to evaluate interactions between TNF-alpha and insulin on circulating leptin levels among normal and overweight children. DESIGN AND METHODS: After multi-stage sampling, we randomly selected 1,500 school children in this survey. All children completed a questionnaire on their disease history and lifestyle characteristics. We measured body weight, height, waist and hip circumference of children and calculated BMI and Waist-to-hip ratio (WHR). We also measured plasma tumor necrosis factor-receptor 1 (TNF-R1) by ELISA, plasma insulin and circulating leptin levels by RIA using commercial kits. We divided the children into normal or overweight groups using BMI criteria (85th percentile) to evaluate the relationship of TNF-R1 and insulin on circulating leptin concentrations. RESULTS: In general, boys were taller, heavier and had higher TNF-R1 and lower leptin levels than girls. Plasma leptin levels were positively correlated with anthropometric variables and insulin levels among children in both genders. In multivariate regression analyses, plasma insulin levels were significantly positive associated with leptin levels in normal weight children. Plasma TNF-R1 levels were positively associated with leptin levels even after adjusting for BMI in girls only. CONCLUSIONS: From this study, we found that plasma insulin plays certain role in leptin expression among normal weight children. However, TNF-R1 plays a more significant role in leptin expression among girls only.     

福州市儿童青少年体质指数与血压的相关性分析

目的分析福州市7¹8岁儿童青少年体质指数与血压的相关性,为开展相关的健康教育、健康促进提供基线资料。方法随机抽取福州市2个城区中等水平的小学和中学各一所,从各年级每个年龄段随机抽取至少20人,男女各半,共调查718岁儿童青少年体质指数与血压的相关性,为开展相关的健康教育、健康促进提供基线资料。方法随机抽取福州市2个城区中等水平的小学和中学各一所,从各年级每个年龄段随机抽取至少20人,男女各半,共调查7¹8岁儿童青少年590人并进行身高、体重和血压的测量。依据《中国学龄儿童青少年超重肥胖筛查体重指数值分类标准》,将学生分为正常、超重和肥胖3类,比较3类学生的收缩压及舒张压。结果 718岁儿童青少年590人并进行身高、体重和血压的测量。依据《中国学龄儿童青少年超重肥胖筛查体重指数值分类标准》,将学生分为正常、超重和肥胖3类,比较3类学生的收缩压及舒张压。结果 7¹2岁男生的超重率和肥胖率均高于1312岁男生的超重率和肥胖率均高于13¹8岁的男生,差异有统计学意义(P<0.05);与正常体重组比较,718岁的男生,差异有统计学意义(P<0.05);与正常体重组比较,7¹2岁、1312岁、13¹8岁和718岁和7¹8岁男生超重肥胖组的SBP和DBP均值以及1318岁男生超重肥胖组的SBP和DBP均值以及13¹8岁和718岁和7¹8岁女生超重肥胖组SBP均值均明显升高,差异有统计学意义(P<0.05);718岁女生超重肥胖组SBP均值均明显升高,差异有统计学意义(P<0.05);7¹2岁男生的BMI与SBP、DBP均呈显著正相关(P<0.05),1312岁男生的BMI与SBP、DBP均呈显著正相关(P<0.05),13¹8岁男生和女生的BMI与SBP、DBP均呈显著正相关(P<0.05);在控制了年龄、性别因素后,718岁男生和女生的BMI与SBP、DBP均呈显著正相关(P<0.05);在控制了年龄、性别因素后,7¹2岁男生及1312岁男生及13¹8岁男生、女生BMI与SBP仍呈独立正相关(P<0.05),1318岁男生、女生BMI与SBP仍呈独立正相关(P<0.05),13¹8岁男生BMI与DBP也呈独立正相关(P<0.05)。结论福州市718岁男生BMI与DBP也呈独立正相关(P<0.05)。结论福州市7¹8岁儿童青少年超重肥胖检出率男生比女生高、低年龄组比高年龄组高;BMI与血压呈独立正相关,BMI与SBP的相关性比BMI与DBP相关性强,年龄越大BMI与SBP的相关性也越强,男生的BMI与SBP、DBP的相关性较女生更为显著。     

不同年龄多囊卵巢综合征患者性激素结合球蛋白与激素指标、血脂指标的相关性

目的分年龄阶段探讨多囊卵巢综合征(PCOS)患者血清性激素结合球蛋白(SHBG)与空腹胰岛素(FINS)、硫酸脱氢表雄酮(DHEA-S)及血脂指标的相关性。方法回顾性分析2017年1月1日至2019年8月30日在山东大学生殖医学研究中心就诊的3349例PCOS患者的FINS、性激素和血脂指标,按照SHBG的参考值下限(32.4 nmol/L)分为SHBG低值组(SHBG<32.4 nmol/L,n=1780)和SHBG高值组(SHBG≥32.4 nmol/L,n=1569),并且分别对每组进行年龄分层(<25岁、25~<30岁、30~<35岁、≥35岁)研究,分析其血清SHBG、FINS、DHEA-S及血脂指标特征。结果在<25岁、25~<30岁、30~<35岁几个年龄阶段PCOS患者中,SHBG低值组患者FINS、DHEA-S水平明显高于SHBG高值组患者,差异有统计学意义(P<0.05);且随着年龄的增长,SHBG低值组中FINS及两组中DHEA-S呈现递减趋势(P<0.05)。在<25岁、25~<30岁、30~<35岁几个年龄阶段PCOS患者中,SHBG低值组患者总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDLC)水平明显高于SHBG高值组患者,差异有统计学意义(P<0.05);SHBG低值组患者高密度脂蛋白胆固醇(HDLC)水平明显低于SHBG高值组患者,差异有统计学意义(P<0.05);且两组TC、TG、LDLC随着年龄的增长呈现递增趋势(P<0.05)。<25岁、25~<30岁和30~<35岁PCOS患者血清SHBG水平与HDLC呈正相关(P<0.05),而与FINS、DHEA-S、TC、TG、LDLC呈负相关(P<0.05)。结论PCOS患者SHBG与FINS、DHEA-S及血脂指标关系密切,SHBG水平的变化也可以作为FINS、DHEA-S和血脂变化的提示指标,为临床提早诊断及及时治疗PCOS提供重要的参考依据。     

Obesity and the development of insulin resistance and impaired fasting glucose in black and white adolescent girls: a longitudinal study

OBJECTIVE: Age at onset of type 2 diabetes has decreased during the past 20 years, especially in black women. Studies of factors associated with insulin resistance and hyperglycemia in preadolescent and adolescent populations are essential to understanding diabetes development. RESEARCH DESIGN AND METHODS: The National Heart, Lung, and Blood Institute (NHLBI) Growth and Health Study (NGHS) is a 10-year cohort study of the development of obesity in black and white girls. Two NGHS centers examined the associations of obesity, puberty, and race with fasting insulin, glucose, and homeostasis model assessment of insulin resistance (HOMA-IR; a calculated index of insulin resistance) measures at 9-10 years of age (baseline) and 10 years later. RESULTS: Black girls had greater baseline and year-10 BMI than white girls, with a greater 10-year incidence of obesity. BMI-insulin correlations were positive in both black and white girls at both visits, but insulin remained higher in black girls after controlling for BMI. In black girls, insulin and HOMA-IR were higher in the prepubertal period (before the emergence of racial differences in BMI), increased more during puberty, and decreased less with its completion. Baseline BMI predicted year-10 glucose and the development of impaired fasting glucose (IFG) in black girls. In white girls, the rate of BMI increase during follow-up predicted these outcomes. The 10-year incidence of diabetes in black girls was 1.4%. CONCLUSIONS: Black-white differences in insulin resistance are not just a consequence of obesity, but precede the pubertal divergence in BMI. The development of IFG appears to be a function of the rate of increase of BMI in white girls and early obesity in black girls.     

Physical activity, cardiovascular fitness, and insulin sensitivity among U.S. adolescents: the National Health and Nutrition Examination Survey, 1999-2002

OBJECTIVE: The purpose of this study was to examine the association of physical activity and cardiovascular fitness (CVF) with insulin sensitivity in a nationally representative sample of U.S. youth. RESEARCH DESIGN AND METHODS: The study included 1,783 U.S. adolescents (11% Mexican American, 14% non-Hispanic black, 63% non-Hispanic white, and 12% other) aged 12-19 years who were examined in the 1999-2002 National Health and Nutrition Examination Survey. Physical activity was assessed by questionnaire and expressed in units of MET hours per week. Predicted maximal oxygen uptake (Vo(2max), expressed in milliliters per kilogram of body weight per minute), a measure of CVF, was determined by a submaximal multistage treadmill test. Insulin sensitivity was defined by the Quantitative Insulin Sensitivity Check Index. RESULTS: Boys were more likely than girls to be highly active (>or=30 MET h/week; 51 vs. 37%, P < 0.001) and had higher levels of CVF (mean Vo(2max) 47 vs. 39 ml x kg(-1) x min(-1), P < 0.001). Sex-specific multiple regression models controlled for age, race/ethnicity, and BMI showed that in boys, high levels of physical activity and high levels of CVF were significantly and positively associated with insulin sensitivity (beta = 0.84, P < 0.001 and beta = 0.82, P = 0.01, respectively). Among girls, insulin sensitivity was not significantly associated with physical activity or with CVF but was inversely and significantly associated with BMI. CONCLUSIONS: Increasing physical activity and CVF may have an independent effect of improving insulin sensitivity among boys. For girls, the primary role of physical activity may be in weight maintenance.     

Blood pressure, height, weight and body mass index of primary school students in a low socio-economic district in Turkey

Aim:  This study was conducted to evaluate the growth and blood pressure measurements of the students.
Background:  School health services are important to evaluate, protect and to improve the health status of the students. This study was conducted to evaluate the growth and blood pressure measurements of the students who were registered in a primary school with low socio-economic level in Kayseri Province in Türkiye between 1 April 2004 and 30 May 2004. The data were collected using questionnaire and health-screening forms.
Findings:  It was determined that the average age was 9.77 ± 2.41 in girls and 10.16 ± 14.70 in boys. It was observed that the average height was 137.95 ± 14.70 cm, and the average weight was 33.07 ± 10.08 kg for all students. The girls between 10 years and 12 years old had a better average body mass index (kg/m²) (BMI) compared with boys. Boys between 6 years and 9 years old had a better BMI than the girls. The difference between the groups was considered statistically important ( P  = 0.006 and P  = 0.002, respectively). Furthermore, 4.9% of the students were underweight and 2.2% of the students were obese. It was thought that there was a positive correlation among height, weight, BMI, age and the blood pressure values; and as BMI and age increased, so did the blood pressure value.
Conclusion:  Cooperation and dialogue need to be established among the school directorate, the families and the students to promote and encourage proper growth development and nutrition of the students within the school health services.     

Relation of birth weight to fasting insulin,insulin resistance,and body size in adolescence

OBJECTIVE: A relationship between birth weight and the insulin resistance syndrome has been reported in adults but has not been defined in adolescents. RESEARCH DESIGN AND METHODS: Data were analyzed in 296 children (132 girls and 164 boys) mean age 15.0 +/- 1.2 years who had euglycemic insulin clamp studies (intravenous administration of 1 mU. kg(-1). min(-1) of insulin balanced by a variable infusion of 20% glucose to maintain blood glucose at 100 mg/dl). Insulin sensitivity (M(LBM)) was determined by glucose uptake per kg lean body mass (LBM), and parents reported birth weight. RESULTS: Birth weight ranged from 1,021 to 4,848 g (mean +/- SD 3,433 +/- 551), with 4.0% <2,500 g. Fat mass and BMI had U-shaped relations with birth weight after adjustment for race, age, sex, and blood pressure. Lean mass index (lean mass/height squared) was stable across birth weight quartiles. Fasting insulin decreased nonsignificantly across birth weight quartiles but became significant after adjustment for adolescent weight (P = 0.008). Although M(LBM) was highest in the highest birth weight quartile, the pattern was not significant. Triglycerides tended to increase with birth weight, whereas LDL cholesterol (LDL-C) and HDL cholesterol (HDL-C) tended to decrease. Blood pressure was unrelated to birth weight. CONCLUSIONS: In this cohort, fat mass was greater in adolescents with low and high birth weight; fasting insulin was lower with higher birth weight after adjustment for adolescent weight. Insulin sensitivity increased nonsignificantly with birth weight.     

IGF-binding protein-1 levels are related to insulin-mediated glucose disposal and are a potential serum marker of insulin resistance

OBJECTIVE: IGF-binding protein (IGFBP)-1 is negatively regulated by insulin. We determined whether the measurement of IGFBP-1 in serum is a useful marker of insulin resistance. RESEARCH DESIGN AND METHODS: Twenty-three subjects underwent a euglycemic insulin clamp. Glucose disposal rates (M) were then correlated with measurements of IGFBP-1, fasting insulin levels, homeostasis model assessment (HOMA), and BMI. RESULTS: IGFBP-1 levels more strongly correlated with M (R = 0.73) than the other parameters such as BMI or HOMA. The level of this protein decreased in individuals who became more insulin sensitive by exercise training. CONCLUSIONS: These studies show a strong correlation between insulin sensitivity and the serum levels of IGFBP-1. These studies suggest, therefore, that measurement of this protein may be valuable in identifying those individuals with insulin resistance and those individuals who respond to interventional strategies.     

Prevalence and determinants of insulin resistance among U.S. adolescents: a population-based study

OBJECTIVE: We sought to examine the distribution of insulin and homeostasis model assessment of insulin resistance (HOMA-IR) and associations of HOMA-IR with sex, race/ethnicity, age, and weight status, as measured by BMI, among U.S. adolescents. RESEARCH DESIGN AND METHODS: Of 4,902 adolescents aged 12-19 years who participated in the National Health and Nutrition Examination Survey 1999-2002, analysis was performed for a nationally representative subsample of 1,802 adolescents without diabetes who had fasting laboratory measurements. The main outcome measure was HOMA-IR, calculated from fasting insulin and glucose and log transformed for multiple linear regression analyses. RESULTS: In adjusted regression models that included age and weight status, girls had higher HOMA-IR than boys and Mexican-American children had higher HOMA-IR levels than white children. There were no significant differences in adjusted HOMA-IR between black and white children. Obese children (BMI >/=95th percentile) had significantly higher levels of HOMA-IR compared with children of normal weight (BMI <85th percentile) in adjusted comparisons (mean HOMA-IR 4.93 [95% CI 4.56-5.35] vs. 2.30 [2.21-2.39], respectively). Weight status was by far the most important determinant of insulin resistance, accounting for 29.1% of the variance in HOMA-IR. The prevalence of insulin resistance in obese adolescents was 52.1% (95% CI 44.5-59.8). CONCLUSIONS: Obesity in U.S. adolescents represents the most important risk factor for insulin resistance, independent of sex, age, or race/ethnicity. The prevalence of insulin resistance in obese children foreshadows a worrisome trend for the burden of type 2 diabetes in the U.S.     

Changes of alkaline phosphatase, inorganic phosphorus and total calcium in sera of 11 to 17 year old healthy adolescents, and their relationship to growth

A semi-longitudinal study in 111 healthy school children, 11 years old, was started in May 1976 to evaluate age-related "normal-ranges" of two so-called "routine" blood parameters during adolescence. Follow-up examinations were performed at one-year intervals until 1982. In this paper growth velocity is described and results of estimations of alkaline phosphatase, inorganic phosphorus (Pi) and total calcium (Ca) are presented and compared with values in the literature. Peak growth velocity in girls (5.94 +/- 1.92 cm/year) occurred between 11 and 12 years, in boys (7.73 +/- 2.4 cm/year) between the age of 12 and 13 years; from the age of 14 years onwards boys were significantly taller than girls. A strong relationship (p less than 0.05) between growth and alkaline phosphatase could be shown throughout the period observed. Alkaline phosphatase activity varied within a wide range and reached mean peak values at the age of 11 years in girls (470.9 +/- 114.8 U/l) and the age of 13 in boys (514.4 +/- 135.7 U/l). Afterwards, alkaline phosphatase activity decreased towards adult levels. Inorganic phosphorus constantly decreased in both boys and girls until the age of 16, while from the age of 16 to 17 years a significant increase could be observed in both sexes. Total calcium values showed a significant increase between 12 and 13 years in boys and between 13 and 14 years in girls; after the age of 14 values decreased significantly in both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Leptin levels and body composition in children and adolescents with type 1 diabetes

The purpose of this study was to determine the relationship between serum leptin levels and body composition and to evaluate the variables related to disease in children and adolescents with type 1 diabetes. We studied 49 diabetic patients aged 6-16 years (age: 11.2+/-2.9 years, M/F: 26/23), and 37 healthy controls. Body composition was determined by dual-energy X-ray absorptiometry. Serum leptin, glycated hemoglobin (HbA1c), free thyroxin, thyrotropin, testosterone and estradiol levels were measured in patients and controls. We did not observe significant difference in serum leptin levels between patients and controls. Girls had significantly higher serum leptin levels than boys in both patient and control groups. Serum leptin levels did not correlate significantly with HbA1c, disease duration or daily insulin dose but, correlated positively with body mass index (BMI) and fat mass (FM) in patients as in controls. Body composition in diabetic girls and boys was similar with respective controls. When analyzed by pubertal stage, BMI, lean body mass (LBM), FM, and total bone mineral density (BMD) were significantly higher in pubertal girls with type 1 diabetes compared to prepubertal ones. In pubertal boys with type 1 diabetes, LBM and FM were significantly higher than prepubertal ones. The results of the present study showed that neither serum leptin levels nor body composition was significantly altered in children and adolescents with type 1 diabetes managed with intensive insulin therapy.     

妊娠期体质量、血清瘦素、脂联素水平与胰岛素抵抗的关系

目的了解妊娠妇女的体质量、血清瘦素、脂联素与胰岛素抵抗之间的关联度。方法通过检测孕妇妊娠早期、中期、晚期血清脂联素(APN),瘦素(LP)、空腹血糖(FINS),同时测量身高,体质量,计算体质指数(BMI)、孕期体质量增加值和胰岛素抵抗指数(HOMA-IR),来探讨孕前体质量、孕期体质量增长与孕妇糖代谢间的关系。结果胰岛素抵抗与孕周无显著性相关,与孕期BMI、血清瘦素以及脂联素水平呈正相关。结论糖尿病对母婴的危害较大,对孕妇的管理和围产期监护,饮食控制治疗尤为重要,要注意补充脂联素充沛的食物,减少可能导致肥胖的食物摄入,才能有效的降低糖尿病的发生率。