Fasting plasma glucose and insulin levels and their relationship to cardiovascular risk factors in children: Bogalusa Heart Study

Plasma glucose and insulin levels were determined in a total biracial community of 3313 children, ages 5-17 years. Black children have significantly higher insulin and lower glucose levels than white children of comparable age and sex. Children of diabetic parents have elevated levels of age- and weight-adjusted fasting cholesterol. Moderate tracking (r = 0.31) of glucose levels over a 3-year period was seen. Insulin levels, however, track well (r = 0.36) only in older children (ages 9-14 years at initial examination). Fasting insulin levels are positively related to measures of obesity, systolic and diastolic blood pressure, triglyceride, beta-lipoprotein cholesterol and pre-beta-lipoprotein cholesterol levels. In addition, insulin levels are negatively related to alpha-lipoprotein cholesterol levels. Fasting glucose levels are positively related to systolic and diastolic blood pressure, triglycerides, pre-beta-lipoprotein cholesterol, and obesity levels. The relationship of plasma glucose and insulin levels to the traditional cardiovascular risk factors in children emphasizes the importance of subtle abnormalities in carbohydrate metabolism in the early natural history of cardiovascular disease.     

The relationship between very-low-density lipoprotein lipid and measures of carbohydrate metabolism in children with different lipoprotein profiles: Bogalusa Heart Study

The relationship of VLDL lipid (cholesterol and triglycerides) levels to fasting and postglucose plasma glucose, plasma glucose, insulin, and free fatty acid (FFA) levels were examined in four subgroups of children (n = 311, ages 6 to 18 years) from a total biracial population whose earlier beta- or pre-beta-lipoprotein cholesterol levels (or both) were in the extreme quintiles or quartiles. High beta-lipoprotein cholesterol strata with or without elevated pre-beta-lipoprotein cholesterol showed significantly high levels of FFA and glucose response (mean, 30 and 60 minutes) to oral glucose load, whereas postglucose insulin responses were markedly higher in the high pre-beta-lipoprotein cholesterol strata. VLDL triglycerides related closely with fasting plasma glucose levels (r = 0.53 to 0.60, P less than 0.001) and to a lesser extent with postglucose plasma glucose response (r = 0.37 to 0.44, P less than 0.001) in all cases. For insulin and FFA, however, correlations were significant only in certain subgroups. Similar relationships were noted for VLDL cholesterol. Measurements relating to carbohydrate tolerance, age, and race accounted for 35% to 48% of the variability in VLDL lipid values. Surprisingly, fasting plasma glucose showed the highest partial regression coefficient for VLDL lipid in all subgroups except high pre-beta-lipoprotein cholesterol and low beta-lipoprotein cholesterol category, in which age was the major predictor variable. These results demonstrate that subtle abnormalities in the above-mentioned metabolic interrelationships are established early in life.     

Coronary heart disease risk factor profiles in black patients with non-insulin-dependent diabetes mellitus: paradoxic patterns.

PURPOSE: Non-insulin-dependent diabetes mellitus (NIDDM) in black Americans consists of two variants: one with insulin resistance and one with normal insulin sensitivity. This study examined whether cardiovascular disease risk factors are significantly different between the two variants. PATIENTS AND METHODS: Twenty-two black patients with NIDDM in near-normoglycemic remission who were receiving no pharmacologic therapy for NIDDM were evaluated for insulin sensitivity by the euglycemic insulin clamp, plasma insulin levels, degree of obesity, glucose metabolism, serum total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol levels, and fasting plasma triglyceride levels. RESULTS: Fifty-nine percent of these patients had normal insulin sensitivity (glucose disposal rate in response to a 1 mU.kg-1.minute-1 insulin infusion greater than 6.0 mg.kg-1.minute-1). The insulin-sensitive patients were less obese (body mass index [BMI] 26.5 +/- 0.6 versus 30.8 +/- 0.9 kg/m2) and had lower fasting plasma insulin levels (56.9 +/- 7.8 versus 88.0 +/- 6.0 pmol/L), lower serum cholesterol (4.47 +/- 0.30 versus 6.39 +/- 0.26 mmol/L), lower serum LDL cholesterol (2.77 +/- 0.31 versus 4.51 +/- 0.27 mmol/L), and lower fasting plasma triglyceride levels (0.83 +/- 0.08 versus 1.45 +/- 0.16 mmol/L) than the insulin-resistant patients. Serum HDL cholesterol was not different between the two groups and was in the high-normal range (1.31 +/- 0.08 and 1.19 +/- 0.07 mmol/L). Univariate analysis demonstrated that serum total cholesterol, LDL cholesterol, and fasting plasma triglycerides were highly correlated with insulin-mediated glucose disposal and fasting plasma insulin. The differences in insulin sensitivity and lipid profiles were independent of obesity, as they were present in six insulin-resistant and six insulin-sensitive patients matched for BMI. CONCLUSIONS: Black patients with the insulin-sensitive variant of NIDDM have a low risk factor profile for cardiovascular disease as compared with those with the insulin-resistant variant, who have a high risk factor profile. A high prevalence of the insulin-sensitive variant of NIDDM in the black population might explain the lower prevalence of angina and myocardial infarction in black patients with NIDDM as compared with white patients with NIDDM.     

Serum lipoprotein profile in children from a biracial community: the Bogalusa Heart Study.

Serum lipoprotein profiles in 3182 children, ages 5-14 years, were studied in a biracial community as part of the Bogalusa Heart Study to describe the early natural history of atherosclerosis. White and black children showed similar mean levels of beta-lipoproteins. Pre-beta-lipoprotein levels, however, were significantly higher in white shildren, while significantly higher levels of alpha-lipoprotein were found in black children. Girls had generally higher levels of beta- and pre-beta-lipoprotein and lower levels of alpha-lipoprotein than boys, although the differences were not significant at each age group. With age there was little change in alpha-lipoprotein levels, a significant increase in pre-beta-lipoprotein levels and a slight but significant decrease between 11 and 14 years in beta-lipoprotein levels. The correlation of alpha-lipoprotein was negative with beta-lipoprotein and, to a greater extent, with pre-beta-lipoprotein. The above inverse relationships were significantly greater in white children than in black children, suggesting differences in lipoprotein profiles in the two groups. Lipoprotein values from a total community study are now available for comparison with the currently recommended upper normal limits for lipoproteins. Since only a very small percentage of children could be considered as hyperlipoproteinemic by those specific levels in this community, we suggest that distributions and percentiles be used to evaluate children for hyperlipoproteinemia.     

Black-white differences in serum lipoproteins during sexual maturation: the Bogalusa Heart Study

Serum lipid, lipoprotein cholesterol, and apolipoprotein (A-I and B) levels were compared between 940 black and 1710 white children who were between the ages of 5 and 17 years. Stratification, matching, and analysis of covariance were used to determine whether black-white differences in levels of serum triglycerides (TG), very low- (VLDL-C), and high- (HDL-C) density lipoprotein cholesterol, and apolipoprotein A-I (apoA-I) could be explained by differences in sexual maturation, obesity, cigarette smoking, alcohol intake, oral contraceptive use, insulin, and glucose. Independently of these covariates, blacks had elevated levels of HDL-C and apoA-I (males only), and whites had increased levels of TG and VLDL-C. All differences were statistically significant at the 0.001 level. In addition, racial contrasts tended to be greater in sexually mature, as compared with prepubertal, males; a similar divergence of levels with sexual maturation was not observed in females. HDL-C levels in white males were partially explained (R2 = 0.12) by sexual maturation, insulin, and obesity; apoA-I levels were associated with only sexual maturation and insulin. Racial differences in levels of serum lipids, lipoprotein cholesterol, and apoA-I in early life, therefore, exist independently of differences in several lipoprotein determinants. Since the initial stages of atherosclerosis begin in the young, these black-white lipoprotein contrasts may influence differences in adult coronary heart disease rates between the races.     

Increasing impact of obesity on serum lipids and lipoproteins in young adults. The Bogalusa Heart Study

Obesity is an important determinant of serum lipids and lipoproteins in adults. Since obesity begins early in life, the impact of obesity of serum lipid and lipoprotein levels was examined in 3311 children and young adults (ages 5 to 26 years) from a totally biracial community. Study subjects were grouped according to race, sex, and age categories (5 to 10 years, 11 to 16 years, 17 to 22 years, and 23 to 26 years), excluding females using oral contraceptives or who were pregnant. Overall, associations increase with age, being most prominently noted in white males. The strong positive relation of ponderosity to low-density lipoprotein cholesterol was indicated in the older age groups with correlation coefficients ranging from r = -.09 in the youngest black males to r = .47 in white males aged 17 to 22 years. A negative association was noted between ponderosity and high-density lipoprotein cholesterol with correlation coefficients ranging from r = .08 in black females aged 17 to 22 years to r = -.39 in the oldest white males. Similar results were seen using subscapular skin-fold thickness as a measure of central obesity. Overweight was defined as exceeding 20% above the National Health Anthropometric and Nutritional Examination Survey II survey 50th percentiles. The prevalence of overweight individuals increased with age, being most prominent in black females. The percent(s) of hypercholesterolemic cases, based on the National Cholesterol Education Program criteria, likewise increased with age. A marked proportion of older white males were classified as borderline high and high for low-density lipoprotein cholesterol. A regression model using subscapular skinfold to predict serum lipids and lipoproteins within each age group indicated a consistent increase in the adverse nature of the lipid profile. Intervention and education programs aimed at reducing obesity at younger ages are recommended to reduce serum lipid and lipoprotein levels developing in young adulthood.     

Relationship between plasma insulin levels and high density lipoprotein cholesterol levels in healthy men

Summary Insulin and high density lipoproteins are considered to play a role in the development of atherosclerosis. In order to study whether there was a relationship between endogenous plasma insulin response and high density lipoproteins, an acute intravenous glucose tolerance test (0.5 g glucose/kg body weight) was performed in 94 healthy men, aged 20–49 years. Cholesterol and triglyceride levels were measured in very low density lipoproteins, low density lipoproteins and high density lipoproteins isolated from fasting serum by preparative ultracentrifugation. The subjects were divided into quartiles according to their fasting and post-glucose load plasma insulin and high density lipoprotein cholesterol levels. The results obtained in the subjects of the upper quartiles were compared with the results obtained in the subjects of the lower quartiles. The mean glucose disappearance rates were within the normal range and did not differ between the upper and lower quartiles. Subjects with high fasting plasma insulin had lower high density lipoprotein cholesterol levels (1.11±0.34 mmol/l, p=0.01) than men with low fasting plasma insulin (1.40±0.37 mmol/l). Higher mean post-glucose plasma insulin was associated with lower high density lipoprotein cholesterol levels (1.18±0.32 mmol/l, p<0.05) and increased high density lipoprotein triglyceride levels (0.14±0.07 mmol/l, p<0.01) when compared with the men with low post-glucose plasma insulin (1.40±0.36 mmol/l and 0.09±0.03 mmol/l respectively). These observations reflect the close relationship between endogenous insulin and lipoprotein metabolism.     

High density lipoprotein and coronary artery disease risk factors in children with different lipoprotein profiles: Bogalusa Heart Study

Serum high density lipoprotein-cholesterol (HDL-C) and apoprotein A-1 (apo A-1) profiles were examined in subgroups of children (n = 338), initially aged 2-14 years, whose earlier beta-lipoprotein cholesterol (beta-LPC) and pre-beta-lipoprotein cholesterol (pre-beta-LPC) measurements were in extreme percentiles of values from a biracial community. Relationships of HDL-C and apo A-1 to serum lipoprotein lipids, apoprotein B (apo B), subscapular skinfold thickness, fasting and 1/2 hr postglucose plasma insulin, and fasting and 1 hr postglucose plasma glucose and free fatty acids were examined. Clustering of several coronary artery disease risk factors in these children was observed. HDL-C levels tended to be low in children having high pre-beta-LPC levels and apo A-1 levels were low in boys having high pre-beta-LPC levels. Within beta- and pre-beta-LPC strata, differences were also observed with respect to race, but not sex, in the mean levels of both HDL-C and apo A-1. HDL-C and apo A.1 were related inversely to subscapular skinfold thickness and plasma insulin levels in all children except those with low levels of both beta-LPC and pre-beta-LPC. Ratios of low density lipoprotein-cholesterol/HDL-C and of apo B/apo A-1 were related positively with other coronary artery disease risk factors except in children having low levels of both beta-LPC and pre-beta-LPC. The magnitude of these associations was greater in whites than in blacks. These observations may help to identify, at an early age, children at high risk of developing coronary artery disease in adulthood.     

The Relationship Between Serum Adiponectin,Tumor Necrosis Factor?Alpha,Leptin Levels and Insulin Sensitivity in Childhood and Adolescent Obesity: Adiponectin is a Marker of Metabolic Syndrome

Objective: This study aimed (a) to investigate the relationship between the degree of obesity and serum adiponectin, tumor necrosis factor (TNF)−α, leptin, insulin levels and the lipid profile; (b) to clarify the relationship between insulin resistance/glucose tolerance and adipocytokine levels; and (c) to investigate the value of adipocytokine levels as a marker of metabolic syndrome (MS).Methods: We studied 151 obese children and adolescents (86 boys and 65 girls; mean age was 12.3±2.4 years). We defined obesity as a body−mass index (BMI) z−score more than 2 SD above the mean for age and sex. The control group consisted of 100 children (48 boys, 52 girls, mean age 12.4±2.5 years). Fasting glucose, insulin levels and lipid profiles were measured in all cases and controls after a 12−hour fast. Adiponectin, TNF−α, and leptin levels were measured in the subjects who participated in the adipocytokine branch of the study. An oral glucose tolerance test (OGTT) was also performed in all obese patients. Obese patients were grouped into three subgroups according to their glucose tolerance and insulin sensitivity assessment, and also according to whether they were grouped as MS or not.Results: Serum levels of total cholesterol, LDL and VLDL cholesterol, log triglyceride, insulin, leptin and TNF−α were higher, whereas HDL and square root adiponectin levels were lower in the obese group when compared with controls. Multiple regression analysis among BMI−z score, LDL, triglyceride, HOMA−IR, leptin and TNF−α as determinants of adiponectin revealed that BMI−z score was the only determinant for adiponectin (r:−0.45, p<0.0001). Adiponectin levels in hyperinsulinemic and impaired glucose tolerance groups (IGT) tended to be lower than in normoinsulinemic obese children, however, the difference was not significant. There was a weak negative correlation between adiponectin levels and increasing severity of insulin resistance (r=−0.23, p=0.005) in the groups of obese subjects. Mean serum adiponectin level in subjects with MS was lower than in subjects without MS (p=0.008).Conflict of interest:None declared.     

Influence of serum lipoproteins and carbohydrate metabolism on erythrocyte membrane composition in children: Bogalusa Heart Study

The influence of serum lipoprotein profile and measures of carbohydrate metabolism on erythrocyte membrane composition were examined in four groups of children (n = 356, ages 6 to 18 years) from a total biracial population whose earlier very low density (VLDL-C) or low density lipoprotein cholesterol (LDL-C) levels (or both) were in the extreme quintiles or quartiles. Erythrocyte membranes of white children contained significantly increased levels of protein (+2.0%) and phospholipid (+2.7%) and decreased levels of neutral sugars (-4.6%) when compared to black children. Membrane neutral sugars were markedly higher (+4.7%) in girls than in boys. Membrane protein was lowest in children characterized by high LDL-C and low VLDL-C. The phospholipid/protein ratio was consistently higher (+1.9%) in the low VLDL-C strata. The relationships between membrane constituents and plasma/serum variables were explored after controlling for race, sex, and age effects and after combining the four selection groups. Less membrane cholesterol was present in the lowest (v highest) quintile of serum LDL-C/high density lipoprotein cholesterol (HDL-C) ratio (P less than 0.01). Membrane phospholipid levels were lower in the highest (v lowest) quintiles of the apoB/apoA-I ratio (P less than 0.01). With respect to measures of carbohydrate tolerance, membrane hexosamine showed low values in the highest (v lowest) quintile of hemoglobin A1c, while the trend was opposite for plasma insulin response (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationships of obesity indices to serum insulin and lipoproteins in relatives of black patients with noninsulin-dependent diabetes mellitus (NIDDM)

We have examined the relationships between obesity indices and various metabolic parameters in seven obese (body mass index (BMI) mean +/- s.e.m. 42 +/- 2.5 kg/m2), ten nonobese (BMI 25.3 +/- 1.2 kg/m2) nondiabetic female relatives of black patients with NIDDM and eight healthy controls (BMI 24.5 +/- 1.1 kg/m2). Despite the greater BMI in the obese relatives, percent body fat was not different from that of the nonobese relatives (38 +/- 2 vs 34 +/- 3 percent). Both values were, however, significantly (P less than 0.05) greater than that of the healthy controls (25 +/- 3 percent). Mean waist-to-hip circumference ratio (WHR) was greatest in obese relatives (0.89 +/- 0.01), intermediate in nonobese relatives (0.83 +/- 0.01) and least in the healthy controls (0.77 +/- 0.04). Mean sum of skinfold thickness from biceps, triceps and subscapular (SS) region was also greatest in obese relatives, intermediate in nonobese relatives and least in controls. Centrality index was not, however, different among the groups. Mean fasting serum glucose levels were slightly higher but not significantly different in the relatives compared to controls (obese 82 +/- 3; nonobese 81 +/- 4; controls 75 +/- 3 mg/dl). Following oral glucose ingestion, serum glucose rose to significantly (P less than 0.05) greater levels at 30, 60 and 90 min in the relative subgroups vs controls. Mean fasting and post-prandial peak serum insulin concentrations were significantly (P less than 0.05-0.01) greater in both relative subgroups vs controls. While mean serum glucose profiles and glucose disappearance decay (KG) following intravenous glucose load were identical in the relatives and controls, serum insulin responses were significantly greater in the relatives. The mean basal and post-stimulation serum C-peptide concentrations were similar in all the three groups, irrespective of the stimulus; thus suggesting a reduced hepatic insulin extraction in the relatives. Fasting serum cholesterol, triglyceride, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C) as well as FFA levels were not different between the relatives and controls despite the hyperinsulinemia in the former group. WHR correlated with basal insulin in the relatives (r = 0.416, P less than 0.05) and controls (r = 0.68, P less than 0.01) but not with stimulated insulin, lipids and lipoproteins in any of the groups. In contrast, both percent BFM and SS thickness correlated significantly (P less than 0.001) with post-glucose insulin concentrations in the relatives only.(ABSTRACT TRUNCATED AT 400 WORDS)     

Relation of risk factor levels in young adulthood to parental history of disease. The CARDIA study

BACKGROUND. The relation between self-reported parental disease and risk factor levels was examined in 2,637 black and 2,478 white men and women aged 18-30 years at the Coronary Artery Risk Development in Young Adults (CARDIA) Study baseline examination (1985-1986). METHODS AND RESULTS. The prevalence of parental disease (at least one parent) in white versus black participants was 44% and 56% for hypertension, 47% and 44% for obesity, 16% and 13% for myocardial infarction, 11% and 17% for diabetes, and 6% and 10% for stroke, respectively. Among these young adults, parental hypertension was associated with higher sex- and age-adjusted systolic and diastolic blood pressure levels. Parental myocardial infarction was associated with higher plasma cholesterol, higher blood pressure levels, and lower high density lipoprotein cholesterol levels in white participants. Parental diabetes was associated with higher fasting blood glucose and insulin levels in all race-sex groups and with higher triglycerides and lower high density lipoprotein cholesterol in black participants only. Parental history of obesity was related to less favorable age- and sex-adjusted lipid levels in white participants and higher blood pressure levels in black participants. Parental history of stroke was associated with higher systolic blood pressure levels in black participants. In general, these differences across family history were predicted only in part by obesity. The prevalence of more than one disease reported in parents occurred more frequently than would have been expected due to chance alone. CONCLUSIONS. These associations between parental disease and risk factors in their adult children probably reflects the impact of both environmental and genetic factors. Parental history may be a useful marker for high risk individuals.     

Divergent responses of serum lipoproteins to changes in dietary carbohydrate and cholesterol in cynomolgus monkeys

The metabolic effects of dietary carbohydrates (simple versus complex) on lipogenesis, glucose, and insulin responses are well known, but information is lacking on the effect of carbohydrate types on different serum lipoprotein fractions. We therefore studied the differences in responses of serum lipids, lipoproteins, apoproteins, and plasma glucose and insulin to changes in dietary carbohydrates and cholesterol in 12 male cynomolgus monkeys (Macaca fascicularis). For 6 weeks, each monkey was fed one of four semipurified, high-carbohydrate (76.5% cal) diets that provided sucrose or starch with and without 1 mg/kcal cholesterol. Sucrose diet without added cholesterol resulted in consistently higher serum total cholesterol than with a similar starch diet. In contrast, cholesterol-enriched starch diet caused marked increase in serum total cholesterol when compared to similar sucrose diet. Neither starch nor sucrose diets elicited a VLDL-triglyceride response. Observations on apoB, VLDL- and LDL-cholesterol levels essentially reflected serum total cholesterol changes by diet. Changes in HDL-subfractions to dietary carbohydrates were seen mainly in HDL₂, with starch producing lower values than sucrose (p < 0.01). Among the four diets, cholesterol, triglyceride and phospholipid contents of HDL₂, as well as apoA-I and apoA-II contents of serum total lipoproteins were lowest with cholesterol-enriched starch diet feeding. High cholesterol diets increased the cholesterol to triglyceride ratios of LDL, irrespective of type of carbohydrate (p < 0.01), whereas the ratios of cholesterol to phospholipids showed significant carbohydrate effect (starch > sucrose) and cholesterol effect for HDL₂. Neither plasma glucose nor insulin showed any diet-related differences. Thus, a high level of dietary carbohydrate with and without added cholesterol provoked divergent responses of serum lipids and lipoproteins between sucrose and starch. Although reasons for the paradoxical responses are not readily apparent, the experiment provides a useful model for further metabolic studies.     

Varied effects of dietary sucrose and cholesterol on serum lipids, lipoproteins and apolipoproteins in rhesus monkeys.

Serum lipid, lipoproteins, apolipoproteins and plasma insulin and glucose were studied in rhesus monkeys (Macaca mulatta) fed high sucrose diets (69%, w/w), with and without added cholesterol. When compared to basal diet, a high sucrose diet with no added cholesterol fed for 6 weeks increased serum total cholesterol and triglycerides by factors of 1.2 and 2.8, respectively. Cholesterol supplementation of sucrose diets increased the serum total cholesterol levels by a factor of 2.2 and decreased the serum triglycerides by 0.47. The serum cholesterol response to experimental diets was reflected predominantly in beta-lipoprotein and to a lesser extent in alpha-lipoprotein. Sucrose diets without cholesterol enriched the beta- and pre-beta-lipoproteins with triglycerides and protein at the expense of cholesterol. On the same diet, the protein content of alpha-lipoprotein increased at the expense of cholesterol and triglycerides. In contrast, dietary cholesterol decreased the triglyceride content and increased the cholesterol content of all the lipoprotein classes. Sucrose feeding seems to increase ApoB more than non-ApoB proteins. The proportion of ApoC-II relative to ApcoC-III increased in each animal on a sucrose diet; exogenous cholesterol further increased this trend. While sucrose diet decreased ApoA-I/ApoA-II ratios, cholesterol supplementation reversed this trend. Dietary sucrose increased the plasma glucose, insulin, and insulin-glucose ratios. The addition of cholesterol also tended to decrease plasma glucose and insulin levels. These observations indicate varied responses of serum lipoproteins and apoproteins to dietary sucrose with and without cholesterol supplementation.     

High-density lipoprotein composition in obesity: interrelationships with plasma insulin levels and body weight

Hyperinsulinism may play a role in the development of atherosclerosis. In this study we analyzed the interrelationships between plasma glucose, insulin, body weight and high-density lipoproteins (HDL) in a group of obese women and faced the question of what is the effect of obesity on insulin, glucose and HDL relationships. HDL cholesterol was significantly lower, while HDL triglycerides resulted significantly higher in the obese women than in the controls. The two groups did not show any difference in the serum concentration of HDL apoprotein A-I and apoprotein A-II. There was an inverse correlation between fasting plasma glucose and summated means of glucose and insulin levels after an oral glucose tolerance test and HDL cholesterol in the two groups; on the contrary a positive relationship between the same parameters and HDL triglyceride occurred. HDL cholesterol was inversely related also to the weight index, while HDL triglyceride concentration was directly correlated with this parameter in the two groups. Partial correlation analysis demonstrates that, when exposed to similar plasma insulin and glucose levels, HDL cholesterol and triglyceride concentrations were no longer correlated with the weight index, and therefore that the significant correlations between these variables are likely to be due to the significant correlations of each of them with plasma glucose and insulin levels. Further studies clarifying the role of glucose and insulin in determining HDL composition would appear important.     

Insulin resistance,high prevalence of diabetes,and cardiovascular risk in immigrant Asians. Genetic or environmental effect?

OBJECTIVES--To compare the prevalence of diabetes, hyperinsulinaemia, and associated metabolic abnormalities in immigrant Asians, Asians in India, and native white British men. DESIGN--Case control study. SETTING--Wythenshawe Hospital, Manchester, United Kingdom, and Maulana Azad Medical School, New Delhi, India. SUBJECTS--Men with angiographically proved coronary artery disease; 83 British Asians, 87 white men, and 30 Indian Asians with age matched controls. INTERVENTIONS--Fasting lipid concentrations, serum glucose, and total insulin concentrations were measured in the fasting state and one and two hours after a 75 g glucose load by mouth. All subjects had a physical examination by the same observer. RESULTS--Asians in the United Kingdom and in India had a higher prevalence of diabetes and impaired glucose tolerance than the white British men. Patients in all three ethnic groups had higher total insulin concentrations than their controls in the fasting state and after the glucose load. British Asian and Indian Asian patients and controls had higher total insulin concentrations than the white men in the fasting state and after the glucose load. Total insulin concentrations were similar in British and Indian Asians, though fasting concentrations were higher in British Asians than Indian Asians. White men had similar cholesterol, lower triglyceride, and higher high density lipoprotein cholesterol concentrations than Asians in the United Kingdom and in India. British Asian patients had higher cholesterol concentrations and British Asian controls had higher triglyceride concentrations than the Indian Asian groups. Asian patients and controls were more active. British and Indian Asian patients had higher waist to hip ratios than controls. The waist to hip ratio was positively correlated with insulin and triglyceride concentrations and negatively correlated with the high density lipoprotein cholesterol concentration. Fasting insulin and high density lipoprotein concentrations were independent predictors of coronary artery disease in white men, whereas in British Asians the waist to hip ratio was the strongest independent predictor. In Indian Asians the waist to hip ratio and high density lipoprotein concentration were independent predictors of coronary artery disease. CONCLUSIONS--Central obesity in the subgroups of Asians studied showed a close association with hyperinsulinaemia and the risk of coronary artery disease. A predisposition to insulin resistance and its metabolic abnormalities in this group of Asians seems to be genetically determined, environmental changes after migration having only a small additional effect.     

Black--white differences in plasma lipoproteins in Cincinnati schoolchildren (one-to-one pair matched by total plasma cholesterol, sex, and age).

The suburban, biethnic Princeton School District provided a suitable population of children (ages 6–17) to test the hypothesis that black schoolchildren have higher high density lipoprotein cholesterol (C-HDL), lower low density lipoprotein cholesterol (C-LDL), and lower triglyceride levels than white schoolchildren when pair-matched by total plasma cholesterol, age, and sex. In 194 black-white pairs of male schoolchildren, black children had higher C-HDL (59.5 ± 13.5 versus 54.8 ± 12.7 mg/dl, p < .001), lower C-LDL (105.7 ± 25.8 versus 108.1 ± 26.7, p < .05), and lower triglyceride (60.7 ± 27.2 versus 71 ± 38.1, p < .001). In 222 black-white pairs of female schoolchildren, black girls had higher C-HDL (57.7 ± 13.1 versus 52.0 ± 11.6 mg/dl, p < .001), lower C-LDL (107.4 ± 24.8 versus 109.6 ± 23.3, p < .05, and lower triglyceride (64.0 ± 24.6 versus 80.2 ± 38.6, p < .001). Mean Quetelet indices (weight/height²) did not differ significantly for the black and white males or females. Since, by matching, the pairs did not differ in age, sex, or total plasma cholesterol, and also did not differ by Quetelet, any differences in C-HDL, C-LDL, and triglyceride can be imputed to racial or other unmeasured, racially related environmental differences in the cholesterol-carrying lipoprotein fractions. Persistence of these black-white differences in lipoproteins into adulthood may be associated with a relatively lower risk of coronary heart disease (CHD) in blacks than in whites, for any given total plasma cholesterol level.     

Interrelationships of lipids,lipoproteins, and clinical chemistry measurements in 1605 schoolchildren,ages 6–17: The princeton schoolchildren study

Interrelationships between clinical chemistry tests (hepatic, renal, and endocrine systems) and lipids-lipoproteins were assessed in 1605 schoolchildren ages 6–17; 916 were randomly selected and 689 selected because of hypercholesterolemia/hypertriglyceridemia from the Cincinnati Lipid Research Clinic's Princeton School study. The clinical chemistry measurements most consistently and uniformly related to lipids and lipoproteins were plasma glucose (GLU), uric acid (UA), serum glutamic oxaloacetic transaminase (SGOT) and hematocrit (HEMO). These relationships were similar quantitatively and qualitatively in 6–11-yr-old and 12–17-yr-old children in both the random and the hyperlipidemic recall groups. The most consistent relationship was a positive one between glucose and triglyceride (TG) and very low density lipoprotein cholesterol (C-VLDL). A second, highly consistent, relationship pattern included an inverse correlation between serum UA and high density lipoprotein cholesterol (C-HDL), and a positive UA-C-VLDL relationship; both were seen in 12–17-yr-old children. Hematocrit was positively associated with TG; SGOT was positively associated with total cholesterol and C-HDL. Many of these relationships, particularly those for plasma GLU and UA, presage relationships observed in normal and hyperlipoproteinemic adults, and may allow a better understanding of the physiology and pathophysiology of lipid and lipoprotein levels.     

Black-white differences in cholesterol levels of serum high-density lipoprotein subclasses among children: the Bogalusa Heart Study

Cholesterol levels of serum high-density lipoprotein (HDL) subclasses, HDL2 and HDL3, were examined in a random subsample (n = 561) of children (7 to 17 years of age) from a total biracial community. Overall, black children in younger (7 to 10 years) and older (11 to 17 years) age groups alike had significantly higher HDL2 cholesterol (HDL2-C) and HDL3-C than their white counterparts. In addition, black children had a relatively higher frequency of joint occurrence of high levels of both HDL2-C and HDL3-C. A significant sex-related difference, with girls showing higher values than boys, was noted among younger age groups for HDL2-C. A male-female crossover trend in HDL2-C levels was apparent only among white children, with girls showing higher values after age 11. Both age and sexual maturation were inversely associated with HDL3-C levels in white children, irrespective of sex (p less than .001). Serum triglycerides were inversely related to both HDL2-C and HDL3-C only in white children (p less than .001). A black-white difference in HDL2-C persisted only among boys and girls in the older age group after adjusting for the covariates (sexual maturation, age, adiposity, oral contraceptive use, cigarette smoking, alcohol use, and serum triglycerides). With respect to HDL3-C, the covariate-adjusted difference remained significant only among boys in the older age group. Metabolic variations between the races in response to both physiologic and environmental factors likely account for the divergence in antiatherogenic HDL pattern.     

Evidence for insulin resistance in black women from South Africa

OBJECTIVE: The rate of glucose disposal was determined in 10 black and 10 white obese nondiabetic urban women from South Africa to assess insulin resistance. DESIGN AND METHODS: Euglycemic hyperinsulinemic clamp and body composition analysis. RESULTS: Age, body mass index (BMI), anthropometric measurements and body composition were similar in both groups of women. A five-level computed tomography (CT) scan showed a similar mean subcutaneous fat mass in both groups of women (black obese women 555 +/- 9.0 vs white obese women 532 +/- 6.0 cm2), but less visceral fat in black obese women (90 +/- 3.0 vs 121 +/- 3.1 cm2; P< 0.05). Black obese women had higher fasting free fatty acid (997 +/- 69 vs 678 +/- 93 micromol/l; P < 0.05) and lactate concentrations (1,462 +/- 94 vs 1,038 +/- 39 micromol/l; P < 0.05), but lower fasting insulin levels (87 +/- 12 vs 155 +/- 9 pmol/l; P < 0.001). Black obese women also had a more favorable HDL: total cholesterol ratio (30.5% vs 23.0%; P< 0.04). The mean glucose disposal rate (M) and disposal expressed as glucose sensitivity index (M/I) were reduced in the black obese women vs white obese women (M: 7.1 +/- 0.8 vs 13.7 +/- 1.0 mmol/kg min(-1) x 100; P< 0.01, and M/I: 0.12 +/- 0.01 vs 0.24 +/- 0.02 mmol/kg x min(-1)/pmol/1 x 1,000; P < 0.01). Only black obese women showed a significant decrease in C-peptide levels during the clamp (2.9 +/- 0.22 vs 1.2 +/- 0.12 nmol/l; P<0.001). During the euglycemic period, the black obese women had higher lactate levels at all time points, but only the white obese women had increased lactate levels (918 +/- 66 to 1,300 +/- 53 micromol/l; P< 0.05). CONCLUSION: Black obese women demonstrate a higher degree of insulin resistance, despite less visceral fat and a higher HDL: total-cholesterol ratio. In addition, endogenous beta-cell secretory function in black obese women appears to be more sensitive to the suppressive effect of exogenous insulin administration. The significant increase in lactate levels in white obese women confirms that they are more insulin sensitive.