High glycosylated hemoglobin levels increase the risk of progression to diabetes mellitus in subjects with glucose intolerance

The relationships between HbA1c level and oral glucose tolerance test (OGTT) at the initial visit and the incidence of diabetes after 5 years of follow-up were investigated in 819 subjects participating in a general health examination. The 100 g OGTT was performed. In order to use WHO criteria, the blood glucose levels of 100 g OGTT corresponding to those of 75 g OGTT were adopted according to the recommendations of the Japan Diabetes Society. Subjects other than diabetic type and IGT (impaired glucose tolerance) were divided into a normal group (fasting blood glucose < 100 mg/dl, 1-h blood glucose < 160 mg/dl, a 2-h blood glucose < 120 mg/dl) and a borderline group (the remaining subjects). In IGT, the incidence of diabetes in the low- (< or = 6.3%), intermediate- (6.4-6.7%) and high-HbA1c (> of = 6.8%) groups were 10.4%, 23.1% and 52.5%, respectively (high vs intermediate and low, P < 0.001; intermediate vs low, P < 0.05). In the borderline group, the incidence were 2.8%, 14.3% and 28.6%, respectively (high and intermediate vs low, P < 0.001). The results showed that the combination of HbA1c level and OGTT enables more precise prediction of progression to NIDDM in subjects with glucose intolerance.     

Reproductive history, glucose tolerance, and NIDDM in Hispanic and non-Hispanic white women. The San Luis Valley Diabetes Study

OBJECTIVE: To ascertain whether childbearing would decrease oral glucose-stimulated insulin and C-peptide levels and increase the risk of NIDDM and impaired glucose tolerance in a population of Hispanic and non-Hispanic white women residing in the San Luis Valley of Colorado. Several investigators have related childbearing to subsequent abnormal glucose tolerance. RESEARCH DESIGN AND METHODS: In a population-based case-control epidemiological study, diabetic patients 20-74 yr of age (n = 196) and randomly sampled control women subjects (n = 735) underwent a glucose tolerance test, a physical examination, and an in-person standardized interview. The relations between the live-birth number and fasting and oral glucose stimulated glucose, insulin and C-peptide concentrations, and NIDDM and impaired glucose tolerance were estimated using linear or logistic regression to adjust for extraneous variables. RESULTS: In women selected as control subjects, the live-birth number was related to a significant decrease in the sum of 1- and 2-h C-peptide concentrations (coefficient = -0.077, P < 0.001) and the logarithm of the sum of 1- and 2-h insulin concentrations (coefficient = -0.014, P = 0.02). After adjustment for subscapular skin-fold thickness, the relative odds of NIDDM for the live-birth number, which was small and of borderline significance, diminished (odds ratio = 1.04 for one birth, P = 0.18). Findings were similar for impaired glucose tolerance. CONCLUSIONS: Childbearing was related to lower C-peptide and insulin levels in Hispanic and non-Hispanic women of the San Luis Valley. It had little apparent effect on later risk of NIDDM or impaired glucose tolerance.     

Lack of association between the Gly40Ser polymorphism in the glucagon receptor gene and NIDDM in Finland

A heterozygous polymorphism changing GGT40 (Gly) to AGT40 (Ser) (Gly40Ser) in the glucagon receptor gene was reported to be associated with non-insulin-dependent diabetes mellitus (NIDDM). A possible involvement of this polymorphism in impaired glucose tolerance was also suggested in a French population. To replicate this finding we screened 311 unrelated NIDDM patients, 101 unrelated individuals with impaired glucose tolerance and 306 control subjects for the presence of the Gly40Ser polymorphism by use of polymerase chain reaction-restriction fragment length polymorphism in a Finnish population. None of the NIDDM or impaired glucose tolerant patients had this polymorphism. Instead, four of the control subjects (1.3%) were heterozygous carriers of the polymorphism (NS). The age, body mass index, 2-h blood glucose level, 2-h insulin level, and incremental insulin are of the four subjects with this polymorphism were similar to those of the control subjects homozygous for the wild type. Taken together, the data do not support the suggested involvement of the Gly40Ser polymorphism in impaired glucose tolerance and the hypothesis of an association between NIDDM and the glucagon receptor gene in this population.     

Effect of exercise intensity on glucose and insulin metabolism in obese individuals and obese NIDDM patients

OBJECTIVE: The primary purpose of this study was to evaluate the acute effect of exercise of differing intensity on plasma glucose and insulin responses to an oral glucose challenge. RESEARCH DESIGN AND METHODS: Six obese men and six obese men with NIDDM of similar age, weight, percentage body fat, and VO2peak participated in the study. Each subject underwent two 7-day exercise programs in a counterbalanced order at 2-week intervals. During each 7-day exercise period, the subjects cycled every day at a power output corresponding to 50% VO2peak for 70 min or 70% VO2peak for 50 min. Muscle glycogen utilization was estimated during exercise on day 7 using a [3H]glucose infusion technique in conjunction with indirect calorimetry. During the day before and after each 7-day exercise period, a 3-h oral glucose tolerance test (OGTT) was administered after a 12-h overnight fast. RESULTS: The average caloric expenditure did not differ between exercise at 50 and 70% VO2peak in both obese and obese NIDDM subjects. However, the carbohydrate oxidation was higher (P < 0.05) during exercise at 70 than 50% VO2peak in obese subjects (77 +/- 5 vs. 68 +/- 6 g) and obese NIDDM subjects (70 +/- 4 vs. 58 +/- 6 g). Muscle glycogen utilization was also higher (P < 0.05) during exercise at 70 than 50% VO2peak in obese subjects (59 +/- 9 vs. 30 +/- 7 g) and in obese NIDDM subjects (48 +/- 5 vs. 24 +/- 5 g). In obese subjects, plasma glucose response area during the OGTT did not change after 7 days of exercise at either 50 or 70% VO2peak. Plasma insulin response area during the OGTT also did not change after 7 days of exercise at 50% VO2peak. However, plasma insulin response area was reduced (P < 0.05) after 7 days of exercise at 70% VO2peak (9,644 +/- 1,783 vs 7,538 +/- 1,522 microU.ml-1.180 min-1). In obese NIDDM subjects, both plasma glucose and insulin response areas during the OGTT did not decrease after 7 days of exercise at either 50 or 70% VO2peak. CONCLUSIONS: It is concluded that the exercise-induced improvement in insulin sensitivity is influenced by exercise intensity in obese individuals. The improved insulin sensitivity after 7 days of exercise at 70% VO2peak in obese individuals may be related to greater muscle glycogen utilization during exercise. The lack of improvement in glucose tolerance and insulin sensitivity after 7 days of exercise at either 50 or 70% VO2peak in obese NIDDM patients may be due to the fact that the NIDDM patients selected in the present study were relatively hypoinsulinemic.     

Cardiovascular risk factors prior to the development of non-insulin-dependent diabetes mellitus in persons with impaired glucose tolerance: the Hoorn Study

The aim of the study was to analyze cardiovascular risk factors as predictors for developing non-insulin-dependent diabetes mellitus (NIDDM) in people with impaired glucose tolerance. A cross-sectional survey of glucose tolerance was conducted in people, aged 50-74, who were randomly selected from the registry of the middle-sized town Hoorn (The Netherlands). Based on the mean values of two oral glucose tolerance tests, people were classified in glucose tolerance categories according to the WHO criteria. The mean follow-up time was 36 months (range 13-55 months). The cumulative incidence of NIDDM was 34% (95% CI 16.9-45.1). In multiple logistic regression analysis, cardiovascular risk factors at baseline did not predict the conversion from impaired glucose tolerance to NIDDM, in contrast with the two-hour plasma glucose level (odds ratio 3.56, p < 0.001) and the fasting proinsulin level, as one of the determinants of beta-cell dysfunction (Odds ratio 2.1, p < 0.05). The baseline HDL-cholesterol level, one of the components of the insulin resistance syndrome, was associated with the conversion from impaired glucose tolerance to normal glucose tolerance (Odds ratio 1.58, p < 0.05). The results of our study seem to support the hypothesis that conversion from impaired glucose tolerance to normal glucose tolerance depends on insulin resistance and the development of NIDDM from impaired glucose tolerance depends on beta-cell dysfunction.     

Gestational diabetes: antepartum characteristics that predict postpartum glucose intolerance and type 2 diabetes in Latino women

We examined antepartum clinical characteristics along with measures of glucose tolerance, insulin sensitivity, pancreatic beta-cell function, and body composition in Latino women with gestational diabetes mellitus (GDM) for their ability to predict type 2 diabetes or impaired glucose tolerance (IGT) within 6 months after delivery. A total of 122 islet cell antibody-negative women underwent oral and intravenous glucose tolerance tests (OGTT; IVGTT), hyperinsulinemic-euglycemic clamps, and measurement of body fat between 29 and 36 weeks' gestation and returned between 1 and 6 months postpartum for a 75-g OGTT. Logistic regression analysis was used to examine the relationship between antepartum variables and glucose tolerance status postpartum. At postpartum testing, 40% of the cohort had normal glucose tolerance, 50% had IGT, and 10% had diabetes by American Diabetes Association criteria. Independent antepartum predictors of postpartum diabetes were the 30-min incremental insulin:glucose ratio during a 75-g OGTT (P = 0.0002) and the total area under the diagnostic 100-g glucose tolerance curve (P = 0.003). Independent predictors of postpartum IGT were a low first-phase IVGTT insulin response (P = 0.0001), a diagnosis of GDM before 22 weeks' gestation (P = 0.003), and weight gain between prepregnancy and the postpartum examination (P = 0.03). All subjects had low insulin sensitivity during late pregnancy, but neither glucose clamp nor minimal model measures of insulin sensitivity in the 3rd trimester were associated with the risk of IGT or diabetes within 6 months' postpartum. These results highlight the importance of pancreatic beta-cell dysfunction, detectable under conditions of marked insulin resistance in late pregnancy, to predict abnormalities of glucose tolerance soon after delivery in pregnancies complicated by GDM. Moreover, the association of postpartum IGT with weight gain and an early gestational age at diagnosis of GDM suggests a role for chronic insulin resistance in mediating hyperglycemia outside the 3rd trimester in women with such a beta-cell defect.     

Alterations in glucose metabolism in the elderly patient with diabetes

OBJECTIVE: To determine the alterations in glucose metabolism in elderly patients with NIDDM. RESEARCH DESIGN AND METHODS: We studied 9 healthy elderly control subjects (73 +/- 1 yr of age; body mass index 25.7 +/- 0.4 kg/m2) and 9 untreated elderly NIDDM patients (72 +/- 2 yr of age; BMI 25.9 +/- 0.5 kg/m2). Each subject underwent a 3-h oral glucose tolerance test (40 g/m2); a 2-h hyperglycemic glucose clamp study (glucose 5.4 mM above basal); and a 4-h euglycemic insulin clamp (40 mM.m2.min-1). Tritiated glucose methodology was used to measure glucose production and disposal rates during the euglycemic clamp. RESULTS: Patients with NIDDM had a higher fasting glucose (9.3 +/- 0.3 vs. 5.1 +/- 0.1 mM in control subjects vs. NIDDM patients, respectively, P < 0.001) and a greater area under the curve for glucose during the OGTT (16.0 +/- 0.6 vs. 6.7 +/- 0.3 mM in control subjects vs. NIDDM patients, respectively, P < 0.01) than the healthy control subjects. During the hyperglycemic clamp, patients with NIDDM had an absent first-phase insulin response (112 +/- 6 vs. 250 +/- 31 pM in control subjects vs. NIDDM patients, respectively, P < 0.01), and a blunted second-phase insulin response (159 +/- 11 vs. 337 +/- 46 pM in control subjects vs. NIDDM patients, respectively, P < 0.01). Before the euglycemic clamp, fasting insulin (99 +/- 5 vs. 111 +/- 10 pM in control subjects vs. NIDDM patients, respectively) and hepatic glucose production (11.8 +/- 0.7 vs. 11.5 +/- 0.5 mumol.kg-1-min-1 in control subjects vs. NIDDM patients, respectively) were similar. Steady-state (180-240 min) glucose disposal rates during the euglycemic clamp were slightly, but not significantly, higher in the normal control subjects (36.5 +/- 1.1 vs. 33.1 +/- 1.9 mumol.kg-1-min-1 in control subjects vs. NIDDM patients, respectively, NS). CONCLUSIONS: We conclude that NIDDM in nonobese elderly subjects is characterized by a marked impairment in insulin release. This may be attributable to the toxic effects of chronic hyperglycemia on the beta-cell. When compared with age-matched control subjects, the NIDDM patients showed no increase in fasting insulin or hepatic glucose production, and insulin resistance was mild.     

Insulin secretin and resistance accompany immobilization of the aged patient

Physical activity is known to increase glucose tolerance and insulin sensitivity. To examine the influence of physical inactivity on insulin sensitivity in aged people, insulin sensitivity and secretion was measured by using a two-step euglycemic glucose clamp, a glucagon tolerance test (GTT), an oral glucose tolerance test (OGGT) and urinary CPR excretion in 11 aged patients immobilized in bed for more than 12 weeks. The results were compared with those of nine healthy mobile aged controls. The muscle volume of the immobilized patients decreased by 20-25% compared with that of the controls, and insulin sensitivity decreased 50% in each step. These results mean that the immobilized patients had decreased insulin sensitivity and responsiveness, even when there was muscle atrophy. The glucose and insulin responses in both the GTT and OGTT showed that there was a slight decrease in the initial response of insulin in the immobilized patients and was in the controls compared with adolescent controls. There was no difference in the initial response of insulin between the immobilized patients and the aged controls. The ratio of impaired glucose tolerance in the OGTT was 4/11 of the immobilized patients and 3/9 of the controls. Total insulin secretion was increased and insulin sensitivity and responsiveness was decreased in the immobilized patients. This suggests that the decreased insulin sensitivity was compensated for increased by insulin secretion in the immobilized patients.     

Glucose intolerance in chronic respiratory failure

A 75-g oral glucose tolerance test (OGTT) was performed on 18 patients with chronic respiratory failure and without fasting hyperglycemia, positive urine glucose, or hepatic/pancreatic disorders. Underlying diseases in these patients were pulmonary emphysema (11 cases, 61%), pulmonary tuberculosis (5 cases, 28%), and chronic bronchial asthma (2 cases, 11%). The body mass index (mean +/- SD, 17.6 +/- 2.2 kg/m2, P < 0.001) in these patients was significantly lower than that (23.8 +/- 3.1 kg/m2) in normal subjects. The OGTT results showed an impaired glucose tolerance pattern in 9 cases (50%) and a diabetes mellitus pattern in 6 cases (34%). The mean two-hour plasma glucose value in the patients was 9.8 mmol/L. However, insulin secretion responded well to glucose loading. These results suggest that a high proportion of chronic respiratory failure patients may have an intolerance for glucose loading but a normal insulin secretion pattern.     

NIDDM in the elderly

OBJECTIVE: We conducted this study to assess the metabolic alterations in elderly patients with NIDDM. RESEARCH DESIGN AND METHODS: Healthy, lean (n = 15; age, 73 +/- 1 years; BMI, 23.8 +/- 0.5 kg/m2), and obese (n = 10; age, 71 +/- 1 years; BMI, 28.9 +/- 1.2 kg/m2) control subjects and lean (n = 10; age, 75 +/- 2 years; BMI, 24.0 +/- 0.5 kg/m2) and obese (n = 23; age, 73 +/- 1 years; BMI, 29.9 +/- 0.7 kg/m2) NIDDM patients underwent a 3-h glucose tolerance test, a 2-h hyperglycemic glucose clamp study, and a 3-h euglycemic glucose clamp study with tritiated glucose methodology to measure glucose production and disposal rates. RESULTS: Waist-to-hip ratio (WHR) was greater in both lean and obese NIDDM patients than in control subjects. Insulin responses during the oral glucose tolerance test were similar in obese subjects (control subjects: 417 +/- 64 pmol/l; NIDDM patients: 392 +/- 47 pmol/l) but were reduced in lean NIDDM patients (control subjects: 374 +/- 34 pmol/l; NIDDM patients: 217 +/- 20 pmol/l, P < 0.01). Lean and obese NIDDM patients had absent first-phase insulin responses during the hyperglycemic clamp. Second-phase insulin responses were reduced in lean (P < 0.01 vs. control subjects by analysis of variance) but not obese NIDDM patients. Hepatic glucose output was not increased in lean or obese NIDDM patients. Steady-state (150-180 min) glucose disposal rates were 16% less in lean NIDDM patients (control subjects: 8.93 +/- 0.37 mg.kg LBM (lean body mass)-1.min-1; NIDDM patients: 7.50 +/- 0.28 mg.kg LBM-1.min-1, P < 0.05) and 37% less in obese NIDDM patients (control subjects: 8.17 +/- 0.38 mg.kg LBM-1.min-1; NIDDM patients: 5.03 +/- 0.36 mg.kg LBM-1.min-1, P < 0.001). CONCLUSIONS: Lean elderly NIDDM patients have a profound impairment in glucose-induced insulin release but mild resistance to insulin-mediated glucose disposal. Obese elderly NIDDM patients have adequate circulating insulin, but marked resistance to insulin-mediated glucose disposal. Hepatic glucose output is not increased in elderly NIDDM patients.     

Predictable value of fasting blood glucose level for the incidence of non-insulin-dependent diabetes mellitus]

In order to investigate the predictable value of fasting blood glucose (FBG) level for the incidence of non-insulin-dependent diabetes mellitus (NIDDM), 638 nondiabetic subjects who were investigated in 1986 (including 341 subjects with normal glucose tolerance and 297 subjects with impaired glucose tolerance) were reexamined in 1992. The results showed that the 6-year-incidence of NIDDM was significantly increased with rising of baseline FBG level. After adjusting for age, sex and body mass index (BMI), proportional hazard regression analysis showed that FBG level in impaired glucose tolerance group was positively associated with the development of NIDDM (P = 0.0001). Subjects with mean FBG level of 5.19 mmol/L had a higher risk of developing NIDDM than subjects with mean FBG level of 4.61 mmol/L (RR 2.1, 95% CI 1.19-3.74, P = 0.01). The risk ratio of NIDDM was further increased in the group with mean FBG level of 6.l5 mmol/L (RR = 2.9, 95% CI 1.79-4.59, P = 0.0001). The result indicates that FBG level is an independent risk factor for the development of NIDDM.     

Glucose utilization and production in patients with maturity-onset diabetes of the young caused by a mutation of the hepatocyte nuclear factor-1alpha gene

Mutations of the hepatocyte nuclear factor (HNF)-1alpha gene cause impaired insulin secretion and hyperglycemia in patients with maturity-onset diabetes of the young (MODY)3. Whether these mutations also affect glucose metabolism in tissues other than the beta-cell has not yet been documented. We therefore assessed, in five MODY3 patients and a dozen healthy control subjects, insulin secretion, oxidative and nonoxidative glucose disposal, and glucose production during a two-step hyperglycemic clamp and a euglycemic hyperinsulinemic (0.4 mU x kg(-1) x min(-1)) clamp. Compared with healthy control subjects, MODY3 patients had higher fasting plasma glucose (+100%) but similar rates of fasting glucose production and oxidation. Both the early and late phases of insulin secretion were virtually abolished during the hyperglycemic clamp, and glucose production was suppressed by only 43% in MODY3 patients vs. 100% in healthy control subjects. The rate of glucose infusion required to produce a 5 mmol/l increase above basal glycemia was reduced by 30%, net nonoxidative glucose disposal (which is equal to net glycogen deposition) was inhibited by 39%, and net carbohydrate oxidation during hyperglycemia was 25% lower in MODY3 patients compared with control subjects. Insulin-stimulated glucose utilization and oxidation measured during the hyperinsulinemic clamp (at approximately 200 pmol/l insulin) were identical in MODY3 patients and in healthy control subjects, indicating that peripheral insulin sensitivity was not altered. Suppression of endogenous glucose production was, however, mildly impaired. It is concluded that MODY3 patients have severely depressed glucose-induced insulin secretion. The development of hyperglycemia in these patients appears to be caused by a decreased stimulation of glucose utilization, oxidation, and nonoxidative glucose disposal as well as by a blunted suppression of endogenous glucose output. These phenomena are essentially secondary to insulinopenia, whereas insulin sensitivity remains intact.     

Gestational diabetes mellitus and subsequent development of overt diabetes mellitus

GDM develops in 1-3% of all pregnancies. Women with GDM are characterized by a relatively diminished insulin secretion coupled with a pregnancy-induced insulin resistance primary located in skeletal muscle tissue. The cellular background for this insulin resistance is not known. The binding of insulin to its receptor and the subsequent activation of the insulin receptor tyrosine kinase have significant importance for the cellular effect of insulin. Thus, the pathogenesis to the insulin resistance was studied by investigating insulin receptor binding and tyrosine kinase activity in skeletal muscle biopsies from women with GDM and pregnant controls. No major abnormalities were found in GDM wherefore it is likely that the insulin resistance is caused by intracellular defects distal to the activation of the tyrosine kinase. Glucose tolerance returns to normal postpartum in the majority of women with GDM. However, previous studies, in populations quite different from a Danish population, have shown that women with previous GDM have a high risk of developing overt diabetes mellitus later in life. Hence, we aimed to investigate the prognosis of women with previous GDM with respect to subsequent development of diabetes and also to identify predictive factors for the development of overt diabets in these women. A follow-up study of diet treated GDM women diagnosed during 1978 to 1985 at the Rigshospital, Copenhagen was performed. Glucose tolerance was evaluated in 241 women (81% of the GDM population) 2-11 years after pregnancy. Abnormal glucose tolerance was found in 34.4% of the women (3.7% IDDM, 13.7% NIDDM, 17% IGT) in contrast to a control group where none had diabetes and 5.3% had IGT. Logistic regression analysis identified the following independent risk factors for later development of diabetes: a high fasting glucose level at diagnosis of GDM, a delivery more than 3 weeks before term, and an abnormal OGTT 2 months postpartum. Low insulin secretion at diagnosis of GDM was also an independent risk factor. The presence of ICA and GAD-autoantibodies in pregnancy was associated with later development of IDDM. In another study the following techniques: hyperinsulinaemic euglycaemic clamp, indirect calorimetry and tritiated glucose infusion were used to evaluate insulin sensitivity in glucose tolerant nonobese women with previous GDM and controls. A decreased insulin sensitivity due to a decreased non-oxidative glucose metabolism in skeletal muscle was found in women with previous GDM. Hence, the activity of three key enzymes in intracellular glucose metabolism (GS, HK and PFK) was studied in skeletal muscle biopsies obtained in the basal state and after 3 h hyperinsulinaemia, with the aim to identify the cellular defects causing the decreased insulin sensitivity. However, no abnormalities in enzyme activity was found. The same group of previous GDM women had a relatively reduced insulin secretion evaluated by the IVGTT. A longitudinal study of 91 GDM women showed a relatively reduced insulin secretion to oral glucose in pregnancy, postpartum as well as 5-11 years later. Thus the present review has shown that even nonobese glucose tolerant women with previous GDM are characterized by the metabolic profile of NIDDM i.e. insulin resistance and impaired insulin secretion. Hence, the combination of this finding together with the significantly increased risk for development of diabetes indicates that all women with previous GDM should have a regular assessment of their glucose tolerance in the years after pregnancy. The first OGTT should be performed around 2 months postpartum in order to diagnose women already diabetic and to identify women with the highest risk for later development of overt diabetes. Women with previous GDM comprise a target group for future intervention trials with the aim to prevent or delay development of NIDDM and IDDM.     

Establishment of xenografts and cell lines from well-differentiated human thyroid carcinoma

OBJECTIVE: To investigate the acute effect of cigarette smoking on glucose tolerance, insulin sensitivity, serum lipids, blood pressure, and heart rate. RESEARCH DESIGN AND METHODS: This nonrandomized experimental control trial in a tertiary care center included 20 healthy chronic smokers and 20 age-, sex-, and BMI-matched healthy volunteers. Two oral glucose tolerance tests (OGTTs) were performed on each subject. Three cigarettes were smoked during the first 30 min in one of the tests. Serum glucose, insulin, and C-peptide levels were measured every 30 min; the area under the curve (AUC) and the insulin sensitivity index (ISI) were calculated; serum total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels were measured at 0 and 180 min; and blood pressure and heart rate were recorded every 5 min throughout 180 min. RESULTS: Smoking acutely impaired glucose tolerance: the AUC for glucose in smokers was 25.5 +/- 1.03 mmol/l (mean +/- SE) (95% CI 22.9-28) during the smoking OGTT and 21.8 +/- 0.85 mmol/l (CI 19.2-24.3) in the control OGTT (P < 0.01); in nonsmokers, it was 19.7 +/- 0.3 mmol/l (CI 18.8-20.5) in the smoking OGTT and 18.7 +/- 0.35 mmol/l (CI 17.8-19.5) in the control OGTT (P < 0.05). Smoking acutely increased serum insulin and C-peptide levels and decreased ISI only in smokers: ISI in smokers was 55 +/- 2.8 (CI 47.4-62.6) in the control OGTT and 43 +/- 2.7 (CI 35.4-50.6) in the smoking OGTT (P < 0.05). Smoking acutely caused a rise of serum total cholesterol levels in both groups and increased LDL cholesterol and triglyceride serum levels significantly only in smokers (P < 0.05). A significant rise of blood pressure and heart rate while smoking was present in all the subjects. CONCLUSIONS: Smoking acutely impaired glucose tolerance and insulin sensitivity, enhanced serum cholesterol and triglyceride levels, and raised blood pressure and heart rate. These findings support the pathogenetic role of cigarette smoking on cardiovascular risk factors.     

The value of certain parameters in the diagnosis and detection of metabolic X syndrome

Authors summarise their 5-year long experiences on 343 patients about diagnostic methods of metabolic syndrome X and offer a simple possibility for screening of the jeopardized individuals. In a group of patients with hypertension and central obesity (group I: with 2 insulin resistant condition), 229 (89%) out of 255 cases met the basic criteria of the syndrome X which were hypertension, central obesity and high insulin levels for the corresponding blood sugar levels during oral glucose tolerance test (probable insulin resistance). Dyslipidemia was missing in 20% of these people. Hyperinsulinism occurred in 85%, glucose intolerance in 53%, presumable insulin resistance in 90% of cases. Insulin resistance was characterised by late hyperinsulinism (90 and 120 min.) during oral glucose tolerance test. This was the case in people with "diabetoid" glucose responses too, suggesting an early failure of glucose tolerance and/or insulin secretion. Components of syndrome X were present with a lower frequency in 24 patients with obesity (group II), in 35 patients with hypertension (group III) and in 29 patients without obesity or hypertension (group IV), as well. According to central obesity and hypertension, syndrome X could be screened by a probability of 90%. This can be helpful in prevention of NIDDM and coronary heart disease.     

Defects in insulin secretion and action in women with a history of gestational diabetes

Gestational diabetes mellitus (GDM) is associated with defects in insulin secretion and insulin action, and women with a history of GDM carry a high risk for the development of non-insulin-dependent diabetes mellitus (NIDDM). Assessment of subjects with a history of GDM who are currently normoglycemic should help elucidate some of the underlying defects in insulin secretion or action in the evolution of NIDDM. We have studied 14 women with normal oral glucose tolerance who had a history of GDM. They were compared with a group of control subjects who were matched for both body mass index (BMI) and waist-to-hip ratio (WHR). All subjects underwent tests for the determination of oral glucose tolerance, ultradian oscillations in insulin secretion during a 28-h glucose infusion, insulin secretion in response to intravenous glucose, glucose disappearance after intravenous glucose (Kg), and insulin sensitivity (SI) as measured by the Bergman minimal model method. The BMI in the post-GDM women was similar to that in the control subjects (24.9 +/- 1.2 vs. 25.4 +/- 1.4 kg/m2, respectively), as was the WHR ratio (0.80 +/- 0.01 vs. 0.76 +/- 0.01, respectively). The post-GDM women were slightly older (35.2 +/- 0.9 vs. 32.1 +/- 1.4 years, P = 0.04). The fasting plasma glucose levels were significantly higher in the post-GDM group than in the control group (4.9 +/- 0.1 vs. 4.4 +/- 0.1 mmol/l, respectively, P < 0.001) and remained higher at each of the subsequent determinations during the oral glucose tolerance test, although none had a result indicative of either diabetes or impaired glucose tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of noninsulin dependent diabetes mellitus on the prevalence of clinical osteoarthritis. A population based study

OBJECTIVE: To explore the relation between noninsulin dependent diabetes mellitus (NIDDM) and osteoarthritis (OA) in a population. METHODS: The study population included 632 men and 882 women aged 52-95 years from the Rancho Bernardo community. In 1984-87, participants answered questions about history of diabetes and had a standard oral glucose tolerance (OGTT). In 1988-92, subjects completed a questionnaire about history of arthritis, type of arthritis diagnosed, and presence of joint pain. Nurses examined subjects for presence of Heberden's nodes. Subjects with no history of arthritis were compared to those with a history of OA and other types of arthritis with regard to age, body size, and plasma glucose levels. In addition, subjects were classified by diabetes status to determine differences in the prevalence of arthritis and related characteristics. RESULTS: Neither impaired glucose tolerance nor NIDDM was associated with history of OA, regardless of how inclusive the definition of OA, before or after adjustment for age and maximum lifetime obesity. In age and obesity adjusted analyses, men with a history of OA had lower fasting plasma glucose levels than men with no arthritis (100.2 vs. 103.6 mg/dl, p < 0.05), and men with NIDDM had less hand and hip pain than normoglycemic men (p < 0.05). Heberden's nodes were unrelated to glucose tolerance status. CONCLUSION: This population based study found no positive association between clinical OA and NIDDM defined by OGTT. These results are compatible with community based data examining radiographic OA and history of diabetes.     

Gestational diabetes is a herald of NIDDM in Navajo women. High rate of abnormal glucose tolerance after GDM

OBJECTIVE: To estimate the rate of deterioration of glucose tolerance and evaluate risk factors for development of NIDDM in Navajo women with a history of gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS: A retrospective analysis of 111 GDM deliveries over a 4-year period, 1983-1987, was conducted in 1994 to determine glucose tolerance status. Patients who had not developed NIDDM were recalled for a 2-h glucose tolerance test (GTT). Tested and non-tested patients were compared, as estimate of conversion to NIDDM was calculated, and risk factors for NIDDM were evaluated. A life-table analysis was developed to estimate the probability of NIDDM after GDM. RESULTS: At the time of chart review, 32 patients (29%) had already been diagnosed with NIDDM. Of the patients, 79 were offered GTT testing, and 56 (71%) returned for follow-up; 15 were diagnosed with NIDDM and 17 with impaired glucose tolerance (IGT); 47 (42%) and 64 (58%) patients in the cohort had developed NIDDM or NIDDM/IGT at the conclusion of the study period. Patients who developed NIDDM had greater BMIs, parity, and infant weights. Fasting blood glucose > 5.83 mmol/l, GTT > 41.63 mmol/l, and recurrence of GDM were associated with later NIDDM. A life-table analysis estimated a 53% likelihood of having NIDDM at an 11-year follow-up; a second model, based only on patients with known NIDDM status, predicted a 70% rate of NIDDM at an 11-year follow-up. CONCLUSIONS: A high proportion of Navajo women with GDM progressed to NIDDM. Postpartum counseling and periodic GTTs are recommended.     

Determinants of serum leptin levels in Cushing's syndrome

Corticosteroids and insulin increase leptin expression in vivo and in vitro. To investigate whether increased serum cortisol influences serum leptin concentrations in humans, we analyzed fasting serum leptin and insulin levels in 50 patients with Cushing's syndrome [34 female patients: 27 with the pituitary form and 7 with the adrenal form; age, 41.6 +/- 2.7 yr; body mass index (BMI), 29.6 +/- 1.2 kg/m2; 16 male patients all with the pituitary form; age, 39.2 +/- 3.1 yr; BMI, 26.3 +/- 2.3 kg/m2] and in controls matched for BMI, age, and gender. Serum leptin levels were higher in female than in male patients in both the Cushing (P < 0.01) and control (P < 0.001) groups. Disease-specific differences in serum leptin levels were only detected in male (106 vs. 67 pmol/L; Cushing's syndrome vs. control, P < 0.05), not female, patients. Multiple stepwise regression analysis of both patient groups revealed insulin as the best predictor of serum leptin concentrations, accounting for 37% of the variance in serum leptin levels, in contrast to BMI or mean serum cortisol (as measured by sampling in 10-min intervals over 24 h). In the subgroup of patients (n = 9) with pituitary adenoma, serum leptin levels were reduced after tumor resection, with concurrent decreases in serum cortisol, insulin, and BMI. In conclusion, chronic hypercortisolemia in Cushing's syndrome appears not to directly affect serum leptin concentrations, but to have an indirect effect via the associated hyperinsulinemia and/or impaired insulin sensitivity.     

The efficacy and safety of miglitol therapy compared with glibenclamide in patients with NIDDM inadequately controlled by diet alone

OBJECTIVE: To compare the therapeutic effects of the alpha-glucosidase inhibitor miglitol (BAY m 1099), the sulfonylurea glibenclamide, and placebo on parameters of metabolic control and safety in patients with NIDDM that is inadequately controlled by diet alone. RESEARCH DESIGN AND METHODS: After a 4-week placebo run-in period, 201 patients in 18 centers in 4 countries were randomized in a double-blind manner to miglitol (50 mg t.i.d., followed by 100 mg t.i.d.), glibenclamide (3.5 mg q.d/b.i.d.), or placebo for 24 weeks. Efficacy criteria were changes from baseline of HbA1c, fasting and postprandial blood glucose and insulin levels, body weight, and serum triglycerides. RESULTS: Efficacy was assessed in 119 patients who completed the full protocol, and the results were similar to those obtained in 186 patients who fulfilled the validity criteria for analysis. Compared with placebo, mean baseline-adjusted HbA1c decreased by 0.75% (P = 0.0021) and 1.01% (P = 0.0001) in the miglitol and glibenclamide treatment groups, respectively. Blood glucose decreased slightly in the fasting state and considerably in the postprandial state in both treatment groups but not in the placebo group. Fasting insulin levels increased slightly (NS) in all treatment groups; however, postprandial insulin levels decreased with miglitol, while increasing markedly with glibenclamide (P = 0.0001 between all treatment groups). Gastrointestinal side effects (flatulence and diarrhea) occurred mostly in the miglitol-treated patients, while some glibenclamide-treated patients had symptoms suggestive of hypoglycemia. CONCLUSIONS: Miglitol monotherapy is effective and safe in NIDDM patients. Compared with glibenclamide, it reduced HbA1c less effectively and caused more gastrointestinal side effects. On the other hand, glibenclamide, unlike miglitol, tended to cause hypoglycemia, hyperinsulinemia, and weight gain, which are not desirable in patients with NIDDM.