Hydrochlorothiazide, but not Candesartan, Aggravates Insulin Resistance and Causes Visceral and Hepatic Fat Accumulation

Treatment with angiotensin II receptor blockers is associated with lower risk for the development of type 2 diabetes mellitus compared with thiazide diuretics. The Mechanisms for the Diabetes Preventing Effect of Candesartan Study addressed insulin action and secretion and body fat distribution after treatment with candesartan, hydrochlorothiazide, and placebo. Twenty-six nondiabetic, abdominally obese, hypertensive patients were included in a multicenter 3-way crossover trial, and 22 completers (by predefined criteria; 10 men and 12 women) were included in the analyses. They underwent 12-week treatment periods with candesartan (C; 16 to 32 mg), hydrochlorothiazide (H; 25 to 50 mg), and placebo (P), respectively, and the treatment order was randomly assigned and double blinded. Intravenous glucose tolerance tests and euglycemic hyperinsulinemic (56 mU/m 2 per minute) clamps were performed. Intrahepatic and intramyocellular and extramyocellular lipid content and subcutaneous and visceral abdominal adipose tissue were measured using proton magnetic resonance spectroscopy and MRI. Insulin sensitivity (M-value) was reduced following H versus C and P (6.07±2.05, 6.63±2.04, and 6.90±2.10 mg/kg of body weight per minute, mean±SD; P ≤0.01). Liver fat content was higher ( P <0.05) following H than both P and C. The subcutaneous to visceral abdominal adipose tissue ratio was reduced following H versus C and P ( P <0.01). Glycosylated hemoglobin, alanine aminotransferase, aspartate aminotransferase, and high-sensitivity C-reactive protein levels were higher ( P <0.05) after H, but not C, versus P. There were no changes in body fat, intramyocellular lipid, extramyocellular lipid, or first-phase insulin secretion. Blood pressure was reduced similarly by C and H versus P. In conclusion, visceral fat redistribution, liver fat accumulation, low-grade inflammation, and aggravated insulin resistance were demonstrated after hydrochlorothiazide but not candesartan treatment. These findings can partly explain the diabetogenic potential of thiazides.

Sex- and depot-specific lipolysis regulation in human adipocytes: interplay between adrenergic stimulation and glucocorticoids

The purpose of this investigation was to explore interactions between adrenergic stimulation, glucocorticoids, and insulin on the lipolytic rate in isolated human adipocytes from subcutaneous and omental fat depots, and to address possible sex differences. Fat biopsies were obtained from 48 nondiabetic subjects undergoing elective abdominal surgery. Lipolysis rate was measured as glycerol release from isolated cells and proteins involved in lipolysis regulation were assessed by immunoblots. Fasting blood samples were obtained and metabolic and inflammatory variables were analyzed. In women, the rate of 8-bromo-cAMP- and isoprenaline-stimulated lipolysis was approximately 2- and 1.5-fold higher, respectively, in subcutaneous compared to omental adipocytes, whereas there was no difference between the two depots in men. Dexamethasone treatment increased the ability of 8-bromo-cAMP to stimulate lipolysis in the subcutaneous depot in women, but had no consistent effects in fat cells from men. Protein kinase A, Perilipin A, and hormone sensitive lipase content in adipocytes was not affected by adipose depot, sex, or glucocorticoid treatment. In conclusion, catecholamine and glucocorticoid regulation of lipolysis in isolated human adipocytes differs between adipose tissue depots and also between sexes. These findings may be of relevance for the interaction between endogenous stress hormones and adipose tissue function in visceral adiposity and the metabolic syndrome.

The effect of polymorphisms in the renin-angiotensin-aldosterone system on diabetic nephropathy risk

OBJECTIVES

The risk of diabetic nephropathy (DN) can be increased by elevated intraglomerular pressure and glomerular filtration rate, leading to glomerular damage. This can be controlled by the renin-angiotensin-aldosterone (RAA) system, which has an important function regulating both systemic and intrarenal blood pressure. Smoking increases the risk of DN, but not all diabetic patients who smoke develop DN. There is a possibility that smoking has different effects depending on the different genotypes of the individual. We investigated the association of DN with seven polymorphisms in the RAA system and their possible interaction with smoking.

SUBJECTS AND METHODS

In the present case-control study, type 1 diabetic patients with diabetes duration > or =20 years, without albuminuria and without antihypertensive treatment (n=197), were included as controls. An albumin excretion rate (AER) of 20-200 microg/min (n=73) was considered as incipient DN, and an AER >200 microg/min was considered as overt DN (n=48). Smoking habits were obtained from questionnaires.

RESULTS

Homozygosity for the A allele, of the angiotensin II type 1 receptor (AGTR1) A1166C polymorphism, was associated with increased risk of overt DN (OR=3.04; 99% CI=1.02-9.06), independently of the other associated variables: age, duration of diabetes, ever smoking, HbA1c, and sex. The effect of the AA genotype was enhanced to a four times risk increase among ever-smoking patients. Two alleles of the microsatellite marker adjacent to the angiotensinogen gene were less common among nephropathy cases than among controls, but this was not significant when controlling for the same variables as above.

CONCLUSIONS

The risk of having overt DN was increased in patients homozygous for the A1166 allele, and smoking seemed to enhance the effect of the AGTR1 genotype.

Fatty acid profile of the erythrocyte membrane preceding development of Type 2 diabetes mellitus

BACKGROUND AND AIMS

The respective roles of dietary fatty acids in the pathogenesis of diabetes are as yet unclear. Erythrocyte membrane fatty acid (EMFA) composition may provide an estimate of dietary fatty acid intake. This study investigates the relation between EMFA composition and development of Type 2 diabetes mellitus.

METHODS AND RESULTS

In a nested case-referent design we studied 159 individuals tested as non-diabetic at baseline who after a mean observation time of 5.4+/-2.6years were diagnosed with Type 2 diabetes mellitus and 291 sex- and age-matched referents. Higher proportions of pentadecanoic acid (15:0) and heptadecanoic acid (17:0) were associated with a lower risk of diabetes. In accordance with earlier findings, higher proportions of palmitoleic (16:1 n-7), dihomo-gamma-linolenic (20:3 n-6) and adrenic (22:4 n-6) acids were associated with increased risk, whereas linoleic (18:2 n-6) and clupanodonic (22:5 n-3) acids were inversely associated with diabetes. After adjustment for BMI, HbA1c, alcohol intake, smoking and physical activity the only significant predictors were 15:0 and 17:0 as protective factors and 22:4 n6 as risk factor.

CONCLUSION

In accordance with previous studies, our results indicate that EMFA-patterns predict development of Type 2 diabetes mellitus. The inverse association with two saturated fatty acids, previously shown to reflect consumption of dairy products, is a new finding.

Ketoacidosis occurs in both Type 1 and Type 2 diabetes--a population-based study from Northern Sweden

AIMS

To determine the occurrence of diabetic ketoacidosis (DKA) in adult Type 2 and Type 1 diabetic patients in Northern Sweden and to determine whether DKA presents with a different clinical picture in Type 2 compared with Type 1 diabetic subjects.

METHODS

All adult patients from a hospital catchment area in Northern Sweden with diagnosed DKA episodes during 1997-2000 were included in a retrospective study. Medical records and laboratory reports were analysed.

RESULTS

During the years 1997 to 2000, the average annual incidence rate for DKA was 5.9 per 100 000 adult inhabitants. Twenty-five patients developed DKA, eight (32%) had Type 2 diabetes, while 17 (68%) had Type 1 diabetes. Type 2 diabetic patients with DKA were older and had higher levels of C-peptide than Type 1 diabetic patients. On admission because of DKA, a similar degree of hyperglycaemia was present in Type 1 and Type 2 patients. Metabolic acidosis was more severe in Type 1 compared with Type 2 diabetic patients. In 50% of the Type 2 diabetic patients, diabetes was diagnosed at the episode of DKA.

CONCLUSIONS

DKA occurs in Caucasian Type 2 diabetic patients within a Swedish population. Although the frequency of DKA is much higher in Type 1 diabetic patients, Type 2 diabetes may account for as much as one-third of the overall DKA cases.

Gender differences and temporal variation in the incidence of type 1 diabetes: results of 8012 cases in the nationwide Diabetes Incidence Study in Sweden 1983-2002

OBJECTIVES

To establish the gender difference amongst newly diagnosed type 1 diabetic patients aged 15-34 years, considering age at diagnosis, temporal trend and seasonal variation at time of diagnosis.

STUDY DESIGN

A population-based prospective study with a mean annual population at risk of 2.3 million.

SETTING

All departments of medicine, endocrinology and paediatrics and primary health care units in Sweden.

SUBJECTS

Incident cases of diabetes aged 15-34 years at diagnosis 1983-2002. MEASURE INSTRUMENT: Basic characteristics of patients at diagnosis were reported by the diagnosing doctor on a standardized form. Level of ascertainment was estimated at 80-90%.

RESULTS

Amongst all incident cases (n = 8012), 74% was diagnosed with type 1 diabetes. The mean annual incidence rate of type 1 diabetes was 12.7/100,000, in men 16.4/100,000 and in women 8.9/100,000. The incidence of type 1 diabetes decreased slowly by increasing age but was in all age groups higher in men, yielding an overall male/female ratio of 1.8. In both genders the incidence of type 1 diabetes decreased in average of 1.0% per year. A seasonal pattern with significantly higher incidence during January-March and lower during May-July was seen in both genders.

CONCLUSIONS

A clear male predominance of type 1 diabetes was seen in all ages. The temporal trend and the seasonal pattern was similar in men and women. Hence, internal factors related to the gender rather than differences in the exposure to environmental factors seem to explain the consistent male-female bias in the postpubertal risk of developing type 1 diabetes.

Insulin action and signalling in fat and muscle from dexamethasone-treated rats

Glucocorticoids initiate whole body insulin resistance and the aim of the present study was to investigate effects of dexamethasone on protein expression and insulin signalling in muscle and fat tissue. Rats were injected with dexamethasone (1mg/kg/day, i.p.) or placebo for 11 days before insulin sensitivity was evaluated in vitro in soleus and epitrochlearis muscles and in isolated epididymal adipocytes. Dexamethasone treatment reduced insulin-stimulated glucose uptake and glycogen synthesis by 30-70% in epitrochlearis and soleus, and insulin-stimulated glucose uptake by approximately 40% in adipocytes. 8-bromo-cAMP-stimulated lipolysis was approximately 2-fold higher in adipocytes from dexamethasone-treated rats and insulin was less effective to inhibit cAMP-stimulated lipolysis. A main finding was that dexamethasone decreased expression of PKB and insulin-stimulated Ser(473) and Thr(308) phosphorylation in both muscles and adipocytes. Expression of GSK-3 was not influenced by dexamethasone treatment in muscles or adipocytes and insulin-stimulated GSK-3beta Ser(9) phosphorylation was reduced in muscles only. A novel finding was that glycogen synthase (GS) Ser(7) phosphorylation was higher in both muscles from dexamethasone-treated rats. GS expression decreased (by 50%) in adipocytes only. Basal and insulin-stimulated GS Ser(641) and GS Ser(645,649,653,657) phosphorylation was elevated in epitrochlearis and soleus muscles and GS fractional activity was reduced correspondingly. In conclusion, dexamethasone treatment (1) decreases PKB expression and insulin-stimulated phosphorylation in both muscles and adipocytes, and (2) increases GS phosphorylation (reduces GS fractional activity) in muscles and decreases GS expression in adipocytes. We suggest PKB and GS as major targets for dexamethasone-induced insulin resistance.

Short-term effects of metformin in type 2 diabetes

BACKGROUND

Although metformin is widely used in the management of type 2 diabetes, its mechanism(s) of action is not fully known, and there have been remarkably few reports on short-term effects of the drug. Here, we examined the early effects on glucose and lipid metabolism and on certain adipose tissue and inflammatory markers during treatment for 28 days.

METHODS

Twenty-one patients were randomized to metformin (n = 16) or placebo (n = 5) and studied at baseline, 1, 2 and 4 weeks with blood sampling and oral glucose tolerance tests (OGTT). The active group received 500 mg metformin daily in the first week, 500 mg twice daily during week 2 and 1000 mg twice daily during weeks 3 and 4.

RESULTS

After 7 days of treatment, a reduced area under curve (AUC) for glucose at OGTT with no change in AUC for insulin levels was observed compared to baseline. Insulin sensitivity, as derived from the OGTT by Gutt's index, was increased. Reductions in fasting plasma glucose, total cholesterol and low-density lipoprotein cholesterol appeared after 14 days, and reductions in triglycerides, plasminogen activator inhibitor-1 (PAI-1) and leptin after 28 days of treatment. There were no changes in body weight, adiponectin or C-reactive protein. Compared with placebo, the changes between day 0 and day 28 differed significantly with regard to AUC for glucose at OGTT and Gutt's index, and showed strong trends for PAI-1 and leptin.

CONCLUSIONS

The data demonstrate that in type 2 diabetes, metformin rapidly affects glucose handling without changing the concentrations of insulin. Reductions in PAI-1 and leptin levels indicate that the early effects of metformin involve also the adipose tissue.

Components of metabolic syndrome predicting diabetes: no role of inflammation or dyslipidemia

OBJECTIVE

The diagnostic criteria and the clinical usefulness of the metabolic syndrome (MetSy) are currently questioned. The objective was to describe the structure of MetSy and to evaluate its components for prediction of diabetes type 2 (T2DM).

RESEARCH METHODS AND PROCEDURES

This was a case-referent study nested within a population-based health survey. Among 33,336 participants, we identified 177 initially non-diabetic individuals who developed T2DM after 0.1 to 10.5 years (mean, 5.4 years), and, for each diabetes case, two referents matched for sex, age, and year of health survey. Baseline variables included oral glucose tolerance test, BMI, blood pressure, blood lipids, adipokines, inflammatory markers, insulin resistance, and beta-cell function. Exploratory and confirmative factor analyses were applied to hypothesize the structure of the MetSy. The prediction of T2DM by the different factors was evaluated by multivariate logistic regression analysis.

RESULTS

A hypothetical five-factor model of intercorrelated composite factors was generated. The inflammation, dyslipidemia, and blood pressure factors were predicitive only in univariate analysis. In multivariable analyses, two factors independently and significantly predicted T2DM: an obesity/insulin resistance factor and a glycemia factor. The composite factors did not improve the prediction of T2DM compared with single variables. Among the original variables, fasting glucose, proinsulin, BMI, and blood pressure values were predictive of T2DM.

DISCUSSION

Our data support the concept of a MetSy, and we propose five separate clusters of components. The inflammation and dyslipidemia factors were not independently associated with diabetes risk. In contrast, obesity and accompanying insulin resistance and beta-cell decompensation seem to be two core perturbations promoting and predicting progression to T2DM.

Early changes in glomerular size selectivity in young adults with type 1 diabetes and retinopathy. Results from the Diabetes Incidence Study in Sweden

OBJECTIVE

To investigate the relationship between early-onset retinopathy and urinary markers of renal dysfunction.

RESEARCH DESIGN AND METHODS

The Diabetes Incidence Study in Sweden (DISS) aims to register all new cases of diabetes in young adults (15-34 years). In 1987-1988, 806 patients were reported and later invited to participate in a follow-up study focusing on microvascular complications after approximately 10 years of diabetes. In the present study, 149 patients with type 1 diabetes, completed eye examination, and urine sampling were included.

RESULTS

The patients with retinopathy (n=58, 39%) had higher HbA(1c) (P<.001) and urinary IgG2/creatinine (P<.05) and IgG2/IgG4 ratios (P<.05). Patients with maculopathy had the highest levels. No significant differences in urinary albumin/creatinine, glycosaminoglycans (GAGs)/creatinine, Tamm-Horsfall protein (THP)/creatinine, and IgG4/creatinine ratios were found. Women had higher urinary albumin/creatinine (P<.01) and urinary IgG2/creatinine ratios (P<.01) than men.

CONCLUSIONS

Young adults with type 1 diabetes and early-onset retinopathy had higher IgG2/creatinine and IgG2/IgG4 ratios than patients without retinopathy indicating that retinopathy is associated with a change in glomerular size selectivity. This was found in association with normal urinary albumin and THP excretion and may be suspected to reflect early general vascular changes.

Metabolic stress in insulin's target cells leads to ROS accumulation - A hypothetical common pathway causing insulin resistance

The metabolic syndrome is a cluster of cardiovascular risk factors, and visceral adiposity is a central component that is also strongly associated with insulin resistance. Both visceral obesity and insulin resistance are important risk factors for the development of type 2 diabetes. It is likely that adipose tissue, particularly in the intra-abdominal depot, is part of a complex interplay involving several tissues and that dysregulated hormonal, metabolic and neural signalling within and between organs can trigger development of metabolic disease. One attractive hypothesis is that many factors leading to insulin resistance are mediated via the generation of abnormal amounts of reactive oxygen species (ROS). There is much evidence supporting that detrimental effects of glucose, fatty acids, hormones and cytokines leading to insulin resistance can be exerted via such a common pathway. This review paper mainly focuses on metabolic and other 'stress' factors that affect insulin's target cells, in particular adipocytes, and it will highlight oxidative stress as a potential unifying mechanism by which these stress factors promote insulin resistance and the development and progression of type 2 diabetes.

Work stress and low emotional support is associated with increased risk of future type 2 diabetes in women

A case-referent study nested within a population-based health survey investigated the associations between psychosocial stress, such as work stress and low emotional support, and future development of type 2 diabetes among occupationally working middle-aged men and women. All participants in a health survey conducted during 1989-2000 (n=33,336) in Umeå in northern Sweden, were included. We identified 191 cases, who were not diabetic initially but were diagnosed with type 2 diabetes after 5.4+/-2.6 years. Two age- and sex-matched referents were selected for each case. Multivariate logistic regression analyses and interaction effects between variables were evaluated. In women, passive or tense working situations were associated with future type 2 diabetes with odds ratios 3.6 (95% confidence interval 1.1-11.7) and 3.6 (1.0-13.3), respectively, and also low emotional support 3.0 (1.3-7.0). These associations were not seen in men. In women, they remained after adjustment for BMI, civil status and educational level, and there were also tendencies for interactions between work stress and low emotional support. In conclusion, work stress and low emotional support may increase the risk of type 2 diabetes in women, but not in men. These findings contribute to our understanding of psychosocial stress as potential risk factors for type 2 diabetes in a Swedish population.

Metabolic syndrome: psychosocial, neuroendocrine, and classical risk factors in type 2 diabetes

This article summarizes some aspects of stress in the metabolic syndrome at the psychosocial, tissue, and cellular levels. The metabolic syndrome is a valuable research concept for studying population health and social-biological translation. The cluster of cardiovascular risk factors labeled the metabolic syndrome is linked with low socioeconomic status. Systematic differences in diet and physical activity contribute to social patterning of the syndrome. In addition, psychosocial factors including chronic work stress are linked with its development. Psychosocial factors could lead to metabolic perturbations and increase cardiovascular risk via activation of neuroendocrine responses, for example, in the autonomic nervous system and in several hormonal pathways. High glucocorticoid levels will promote lipid storage in visceral rather than subcutaneous adipose tissue. Adipocytes secrete several proinflammatory cytokines, which considered major contributors to increase in oxidants and cell injury. Upregulation of heme oxygenase 1 (HO-1) and peroxidase in the early development of diabetes produces a decrease in oxidative-mediated injury. Increased HO activity is associated with a significant decrease in superoxide, endothelial cell shedding and blood pressure. Finally, it is proposed that overexpression of glutathione peroxidase in beta cells may protect beta cell deterioration from oxidative stress during development of diabetes and hyperglycemia and this may result in attenuation of beta cell failure. If this proves to be the case, then the scene will be set to develop glutathione peroxidase mimetics for use in preclinical and clinical trials.

Short-term effects of metformin in type 2 diabetes

BACKGROUND

Although metformin is widely used in the management of type 2 diabetes, its mechanism(s) of action is not fully known, and there have been remarkably few reports on short-term effects of the drug. Here, we examined early effects on glucose and lipid metabolism, and on certain adipose tissue and inflammatory markers during treatment for 28 days.

METHODS

Twenty-one patients were randomized to metformin (n = 16) or placebo (n = 5) and studied at baseline, 1, 2 and 4 weeks with blood sampling and oral glucose tolerance tests (OGTT). The active group received 500 mg metformin daily in week 1, 500 mg twice daily in week 2 and 1000 mg twice daily in week 3 and 4.

RESULTS

After 7 days of treatment, a reduced area under curve (AUC) for glucose at OGTT with no change in AUC for insulin levels was observed compared with baseline. Insulin sensitivity, as derived from the OGTT by Gutt's index, was increased. Reductions in fasting plasma glucose, total and LDL-cholesterol appeared after 14 days, and reductions in triglycerides, plasminogen activator inhibitor-1 (PAI-1) and leptin after 28 days of treatment. There were no changes in body weight, adiponectin or C-reactive protein. Compared with placebo, the changes between day 0 and day 28 differed significantly with regard to AUC for glucose at OGTT and Gutt's index, and showed strong trends for PAI-1 and leptin.

CONCLUSIONS

The data demonstrate that in type 2 diabetes metformin rapidly affects glucose handling without changing the concentrations of insulin. Reductions in PAI-1 and leptin levels indicate that the early effects of metformin involve also the adipose tissue.

Fat cell enlargement is an independent marker of insulin resistance and 'hyperleptinaemia'

AIMS/HYPOTHESIS

The aim of this study was to explore whether fat cell size in human subcutaneous and omental adipose tissue is independently related to insulin action and adipokine levels.

MATERIALS AND METHODS

Fat cells were prepared from abdominal subcutaneous biopsies obtained from 49 type 2 diabetic and 83 non-diabetic subjects and from omental biopsies obtained from 37 non-diabetic subjects. Cell size and insulin action on glucose uptake capacity in vitro were assessed in isolated fat cells. Insulin sensitivity in vivo was assessed with euglycaemic-hyperinsulinaemic clamps. Fasting blood samples were collected and adipokines and NEFA were measured.

RESULTS

Negative correlations were found between subcutaneous fat cell size and insulin sensitivity assessed as M-value during clamp and as insulin action on glucose uptake in fat cells in vitro. This was seen in non-diabetic subjects after including age, sex and BMI in the analyses. No such relationship was found in type 2 diabetic subjects. In both groups, subcutaneous fat cell size correlated positively and independently with plasma levels of leptin but not to any of the other assessed adipokines. In non-diabetic subjects, omental fat cell size was independently and negatively correlated with insulin action in subcutaneous, but not omental, fat cells in vitro.

CONCLUSIONS/INTERPRETATION

Fat cell enlargement is associated with insulin resistance in non-diabetic individuals independently of BMI. This was not seen in type 2 diabetic subjects, suggesting that after development of type 2 diabetes other factors, not related to fat cell size, become more important for the modulation of insulin resistance.

Insulin resistance induced by high glucose and high insulin precedes insulin receptor substrate 1 protein depletion in human adipocytes

The aim of this study was to investigate whether high glucose and/or high insulin produces cellular insulin resistance in human adipocytes and, if so, to evaluate the time course and content of key proteins in the insulin signaling pathway. Subcutaneous fat biopsies were taken from 27 nondiabetic subjects. Insulin action in vitro was studied by measurement of glucose uptake after incubation at a physiologic glucose level (6 mmol/L) for 24 hours or with the last 2, 6, or 24 hours at a high glucose level (20 mmol/L) with or without high insulin (10(4)microU/mL). High glucose alone for 24 hours produced a small but significant impairment (by approximately 20%, P < .05) of insulin's effect to stimulate glucose transport, whereas nonstimulated glucose uptake was left intact. In contrast, the combination of high glucose and high insulin for 6 hours or more reduced basal glucose uptake by approximately 40% (P < .05). In addition, insulin-stimulated glucose uptake capacity was reduced by approximately 40% already after 2 hours (P < .05) and reached a maximal decline (by approximately 50%, P < .05) after a 6-hour culture in high glucose and high insulin. Treatment with high glucose and high insulin in combination for at least 6 hours reduced cellular insulin receptor substrate (IRS)-1, but not IRS-2, protein content by approximately 45% or more (P < .05). Moreover, after 24 hours, the ability of insulin to activate protein kinase B (ie, the phosphorylated protein kinase B [pPKB]-protein kinase B ratio) was decreased by approximately 50% (P < .05). No significant effects were seen on insulin signaling proteins or glucose transporter 4 after a long-term high-glucose culture. Culture with high insulin alone (and low glucose, 6 mmol/L) decreased basal and insulin-stimulated glucose uptake in conformity with the high-glucose/high-insulin setting. However, IRS-1 protein content remained unchanged. We conclude that, in adipocytes from healthy humans, high insulin alone for 2 hours or more decrease glucose uptake capacity. Likewise, high glucose and high insulin in combination for 2 hours or more decrease glucose uptake to the same extent as when cells were cultured with high insulin alone but, in addition, with a diminishment in IRS-1 protein lagging behind. Thus, IRS-1 depletion appears to be a secondary phenomenon in this model of insulin resistance. High glucose alone induces only a minor insulin resistance in human fat cells.

Beneficial effects of dalteparin on haemostatic function and local tissue oxygenation in patients with diabetes, severe vascular disease and foot ulcers

INTRODUCTION

A state of hypercoagulation and fibrinolytic dysfunction is present in individuals with diabetes, which may contribute to disturbed skin microcirculation and impaired ulcer healing. We have previously reported an improved outcome of chronic diabetic foot ulcers during treatment with dalteparin. In the present study we investigated the effects of dalteparin on skin microcirculation and haemostatic function.

MATERIALS AND METHODS

87 patients with diabetes, peripheral arterial obliterative disease and chronic foot ulcers were investigated in a prospective, randomised, double-blind and placebo-controlled study. They were randomised to treatment with subcutaneous injections of 5000 U dalteparin (n=44) or placebo (n=43), once daily until ulcer healing or for a maximum of six months. Plasma fibrinogen, fibrin gel structure [permeability coefficient (Ks) and fiber mass/length ratio (mu)], prothrombin fragment 1+2 (F1+2) antigen, plasminogen activator inhibitor-1 (PAI-1) activity and tissue plasminogen activator (tPA) antigen were analysed before randomization (baseline value), and at the end of the treatment period. The skin microcirculation of the foot was investigated by transcutaneous oxygen tension (TcPO(2)) and laser Doppler fluxmetry (LDF).

RESULTS

The changes (Delta-values) of Ks, mu, tPA and TcPO(2) were higher (p<0.05) during treatment with dalteparin, as compared to the changes during treatment with placebo. At baseline, plasma fibrinogen and Ks were significantly correlated to TcPO(2).

CONCLUSIONS

Local skin oxygenation improved and a less thrombogenic fibrin gel structure was formed in patients treated with dalteparin. Beneficial effects on haemostatic function are likely to contribute to the improved skin oxygenation observed during treatment with dalteparin.

Lower levels of plasma 25-hydroxyvitamin D among young adults at diagnosis of autoimmune type 1 diabetes compared with control subjects: results from the nationwide Diabetes Incidence Study in Sweden (DISS)

AIMS/HYPOTHESIS

Low plasma vitamin D concentrations may promote the development of type 1 diabetes. To test this hypothesis, we measured plasma 25-hydroxyvitamin D (25OHD) in young adults with type 1 diabetes.

METHODS

The nationwide Diabetes Incidence Study in Sweden (DISS) covers 15- to 34-year-old people with newly diagnosed diabetes. Blood samples at diagnosis were collected during the 2-year period 1987/1988. Patients with islet antibodies (islet cell antibodies, GAD antibodies or tyrosine phosphatase-like protein antibodies) were defined as having autoimmune type 1 diabetes. Plasma 25OHD was measured in samples taken from 459 patients at the time of diagnosis, and in 138 of these subjects 8 years later. The results were compared with age- and sex-matched control subjects (n=208).

RESULTS

At diagnosis, plasma 25OHD levels were significantly lower in patients with type 1 diabetes than in control subjects (82.5+/-1.3 vs 96.7+/-2.0 nmol/l; p<0.0001). Eight years later, plasma 25OHD had decreased in patients (81.5+/-2.6 nmol/l; p=0.04). Plasma 25OHD levels were significantly lower in diabetic men than in diabetic women at diagnosis (77.9+/-1.4 vs 90.1+/-2.4 nmol/l; p<0.0001) and at follow-up (77.1+/-2.8 nmol/l vs 87.2+/-4.5 nmol/l; p=0.048).

CONCLUSIONS/INTERPRETATION

The plasma 25OHD level was lower at diagnosis of autoimmune type 1 diabetes than in control subjects, and may have a role in the development of type 1 diabetes. Plasma 25OHD levels were lower in men than in women with type 1 diabetes. This difference may be relevant to the high incidence of type 1 diabetes among young adult men.

Insulin resistance, endocrine function and adipokines in type 2 diabetes patients at different glycaemic levels: potential impact for glucotoxicity in vivo

OBJECTIVE

To evaluate the interplay between hyperglycaemia, insulin resistance, hormones and adipokines in patients with type 2 diabetes mellitus (T2DM).

DESIGN AND METHODS

Ten patients with T2DM with good glycaemic control (G), 10 with poor control (P) and 10 nondiabetic control subjects (C) were matched for sex (M/F 6/4), age and body mass index. A hyperinsulinaemic, euglycaemic clamp was performed and cytokines and endocrine functions, including cortisol axis activity were assessed.

RESULTS

Patients with diabetes were more insulin resistant than group C, and group P exhibited the highest degree of insulin resistance (P = 0.01, P vs C). Tumour necrosis factor (TNF)-alpha levels were elevated in patients with diabetes (P = 0.05) and group P had the highest levels of fasting serum cortisol (P = 0.05), nonesterified fatty acids (NEFA; P = 0.06) and C-reactive protein (CRP; P = 0.01). Adiponectin levels were lower in the P group. In partial correlation analyses, significant associations were found: glycaemic level (HbA1c) with insulin resistance, TNF-alpha, CRP and basal and ACTH-stimulated cortisol levels, insulin resistance with plasma NEFA, TNF-alpha and stimulated cortisol levels.

CONCLUSION

Poor glycaemic control in patients with T2DM was associated with insulin resistance and with elevated TNF-alpha, CRP and basal as well as stimulated cortisol levels. Inflammatory mediators, e.g. TNF-alpha, may contribute to insulin resistance in hyperglycaemic patients with T2DM and this might be a partial explanation for glucotoxicity.

Insulin resistance in diabetic nephropathy--cause or consequence?

Insulin resistance (IR) is associated with multiple risk factors for cardiovascular disease. Many studies have shown that IR is present in chronic renal failure (CRF), and recent evidence suggests that IR can also occur in the early stages of renal disease. Patients with diabetic nephropathy (DN) have an increase in cardiovascular mortality, and since IR may be a contributing factor, this emphasizes the importance of a detailed understanding of the mechanisms linking IR and renal dysfunction at different stages of DN. IR can be detected early on in DN, e.g. at the stage of microalbuminuria (MA) and this could indicate a common genetic trait for IR and DN. As DN progresses further, IR is aggravated and it may, in addition to other factors, possibly accelerate the decline in renal function toward end-stage renal disease (ESRD). Several potentially modifiable mechanisms including circulating hormones, neuroendocrine pathways and chronic inflammation, are said to contribute to the worsening of IR. In ESRD, uremic toxins are of major importance. In this review article, we address the association between different stages of DN and IR and attempt to summarize major findings on potential mechanisms linking DN and IR. We conclude that IR is a consequence, and potentially also a cause of DN. In addition, there are probably genetic and environmental background factors that predispose to both IR and DN.

A combination of HbA1c, fasting glucose and BMI is effective in screening for individuals at risk of future type 2 diabetes: OGTT is not needed

OBJECTIVE

To identify a screening model that predicts high risk of future type 2 diabetes and is useful in clinical practice.

DESIGN AND METHODS

Incident case-referent study nested within a population-based health survey. We compared screening models with three risk criteria and calculated sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and attributable proportion. We used fasting plasma glucose (FPG) alone or with an oral glucose tolerance test (OGTT), glycosylated haemoglobin A (HbA1c) (normal range 3.6-5.3%), body mass index (BMI), triglycerides and family history of diabetes (FHD).

SETTING

Participants in a health survey at all primary care centres (n=33,336) and subjects with diagnosed type 2 diabetes in primary and hospital care (n=6088) in Umeå during 1989-2001.

SUBJECTS

Each of the 164 subjects who developed clinically diagnosed type 2 diabetes (median time to diagnosis of 5.4 years) and 304 sex- and age-matched referents without diabetes diagnosis.

RESULTS

Screening models with at least one criterion present had sensitivities of 0.90-0.96, specificities of 0.43-0.57 and PPVs of 8-9%. Combinations of the criteria, FPG>or=6.1 mmol L-1 (capillary plasma), HbA1c>or=4.7% and BMI>or=27 in men and BMI>or=30 in women, had sensitivities, specificities and PPVs of 0.66%, 0.93% and 32%, and 0.52%, 0.97% and 46% respectively. Using FHD as one of three risk criteria showed comparable results. Addition of triglycerides or OGTT did not improve the prediction.

CONCLUSIONS

The combination of HbA1c, FPG and BMI are effective in screening for individuals at risk of future clinical diagnosis of type 2 diabetes. OGTT or FHD is not necessary.

HLA-DQB1 genotypes, islet antibodies and beta cell function in the classification of recent-onset diabetes among young adults in the nationwide Diabetes Incidence Study in Sweden

AIMS/HYPOTHESIS

The World Health Organization considers an aetiological classification of diabetes to be essential. The aim of this study was to evaluate whether HLA-DQB1 genotypes facilitate the classification of diabetes as compared with assessment of islet antibodies by investigating young adult diabetic patients.

SUBJECTS AND METHODS

Blood samples were available at diagnosis for 1,872 (90%) of the 2,077 young adult patients (aged 15-34 years old) over a 5-year period in the nationwide Diabetes Incidence Study in Sweden. Islet antibodies were measured at diagnosis in 1,869 patients, fasting plasma C-peptide (fpC-peptide) after diagnosis in 1,522, while HLA-DQB1 genotypes were determined in 1,743.

RESULTS

Islet antibodies were found in 83% of patients clinically considered to have type 1 diabetes, 23% with type 2 diabetes and 45% with unclassifiable diabetes. After diagnosis, median fpC-peptide concentrations were markedly lower in patients with islet antibodies than in those without (0.24 vs 0.69 nmol/l, p<0.0001). Irrespective of clinical classification, patients with islet antibodies showed increased frequencies of at least one of the risk-associated HLA-DQB1 genotypes compared with patients without. Antibody-negative patients with risk-associated HLA-DQB1 genotypes had significantly lower median fpC-peptide concentrations than those without risk-associated genotypes (0.51 vs 0.74 nmol/l, p=0.0003).

CONCLUSIONS/INTERPRETATION

Assessment of islet antibodies is necessary for the aetiological classification of diabetic patients. HLA-DQB1 genotyping does not improve the classification in patients with islet antibodies. However, in patients without islet antibodies, HLA-DQB1 genotyping together with C-peptide measurement may be of value in differentiating between idiopathic type 1 diabetes and type 2 diabetes.

Excess mortality in incident cases of diabetes mellitus aged 15 to 34 years at diagnosis: a population-based study (DISS) in Sweden

AIMS/HYPOTHESIS

The objective of the study was to analyse the mortality, survival and cause of death patterns in incident cases of diabetes in the 15-34-year age group that were reported to the nationwide prospective Diabetes Incidence Study in Sweden (DISS).

MATERIALS AND METHODS

During the study period 1983-1999, 6,771 incident cases were reported. Identification of deaths was made by linking the records to the nationwide Cause of Death Register.

RESULTS

With an average follow-up of 8.5 years, resulting in 59,231 person-years, 159 deaths were identified. Diabetes was reported as the underlying cause of death in 51 patients (32%), and as a contributing cause of death in another 42 patients (26%). The standardised mortality ratio (SMR) was significantly elevated (RR=2.4; 95% CI: 2.0-2.8). The SMR was higher for patients classified by the reporting physician as having type 2 diabetes at diagnosis than for those classified as type 1 diabetic (2.9 and 1.8, respectively). Survival analysis showed significant differences in survival curves between males and females (p=0.0003) as well as between cases with different types of diabetes (p=0.005). This pattern was also reflected in the Cox regression model showing significantly increased hazard for males vs females (p=0.0002), and for type 2 vs type 1 (p=0.015) when controlling for age.

CONCLUSIONS/INTERPRETATION

This study shows a two-fold excess mortality in patients with type 1 diabetes and a three-fold excess mortality in patients with type 2 diabetes. Thus, despite advances in treatment, diabetes still carries an increased mortality in young adults, even in a country with a good economic and educational patient status and easy access to health care.

Lipoprotein lipase activity/mass ratio is higher in omental than in subcutaneous adipose tissue

BACKGROUND

Lipoprotein lipase (LPL) is important for lipid deposition in adipose tissue (AT) and responds rapidly to changes in the nutritional state. Animal experiments indicate that short-term regulation of LPL is mainly post-translational. Different processing of LPL in different AT depots may play a role in the distribution of lipids in the body.

MATERIALS AND METHODS

Lipoprotein lipase mRNA, mass and activity were measured in pieces of omental adipose tissue (OAT) and subcutaneous adipose tissue (SAT) from 15 subjects undergoing gastrointestinal surgery (four male and 11 female subjects, mean age 54 +/- 5 years, BMI 28 +/- 2 kg m(-2)).

RESULTS

Lipoprotein lipase activity was higher in OAT than in SAT (18 +/- 2.1 compared with 12 +/- 1.6 mU g(-1), P < 0.01), whereas LPL mass was lower in OAT than in SAT (100 +/- 9 compared with 137 +/- 16 mU g(-1), P < 0.05). Consequently, the specific LPL activity (ratio of activity over mass) was approximately twofold greater in OAT compared with SAT. There was correlation between LPL mRNA and LPL activity in SAT (P < 0.05) and a similar tendency in OAT (P = 0.08). There were strong correlations (P < 0.01) for mRNA abundance as well as for LPL activity between the two depots. In contrast there was no correlation between the LPL mass and LPL mRNA or activity in any of the depots.

CONCLUSIONS

These results indicate that long-term regulation, as reflected in the mRNA abundance, is similar in the two types of adipose tissue. The displayed activity reflects the mRNA abundance and the fraction of newly synthesized LPL molecules which the post-translational mechanism allows to become/remain active. This fraction was on average twofold greater in OAT compared with SAT.

Is insulin resistance caused by defects in insulin's target cells or by a stressed mind?

The importance of understanding insulin action is emphasized by the increasing prevalence of insulin resistance in various populations and by the fact that it plays an important pathophysiological role in many common disorders, for example, diabetes, obesity, hypertension and dyslipidemia. The primary factors responsible for the development of insulin resistance are so far unknown, although both genetic and environmental factors are involved. The genetic defects responsible for the common forms of insulin resistance, for example, in type 2 diabetes, are largely unidentified. Some studies from our group as well as by other investigators suggest that cellular insulin resistance is reversible and that it may be secondary to factors in the in vivo environment. These may include insulin-antagonistic action of hormones like catecholamines, glucocorticoids, sex steroids and adipokines as well as dysregulation of autonomic nervous activity and they could contribute to the early development of insulin resistance. Some of these factors can directly impair glucose uptake capacity and this might be due to alterations in key proteins involved in insulin's intracellular signaling pathways. This article briefly summarizes proposed mechanisms behind cellular and whole-body insulin resistance. In particular, we question the role of intrinsic defects in insulin's target cells as primary mechanisms in the development of insulin resistance in type 2 diabetes and we suggest that metabolic and neurohormonal factors instead are the main culprits.

Insulin receptor substrates-1 and -2 are both depleted but via different mechanisms after down-regulation of glucose transport in rat adipocytes

Alterations in muscle and adipose tissue insulin receptor substrate (IRS)-1 and IRS-2 are associated with, and commonly believed to contribute to, development of insulin resistance. In this study, we investigated the mechanisms behind previously observed reductions in IRS levels due to high concentrations of glucose and insulin and their significance in the impairment of glucose uptake capacity in primary rat adipocytes. Semiquantitative RT-PCR analysis showed that insulin (10(4) microU/ml) alone or in combination with glucose (15 mm) markedly suppressed IRS-2 gene expression, whereas IRS-1 mRNA was unaffected by the culture conditions. The negative effect of a high glucose/high insulin setting on IRS-1 protein level was still exerted when protein synthesis was inhibited with cycloheximide. Impairment of glucose uptake capacity after treatment with high glucose and insulin was most pronounced after 3 h, whereas IRS-1 and IRS-2 protein levels were unaffected up to 6 h but were reduced after 16 h. Moreover, impaired glucose uptake capacity could only partially be reversed by subsequent incubation at physiological conditions. These novel results suggest that: 1) in a high glucose/high insulin setting depletion of IRS-1 and IRS-2 protein, respectively, occurs via different mechanisms, and IRS-2 gene expression is suppressed, whereas IRS-1 depletion is due to posttranslational mechanisms; 2) IRS-1 and IRS-2 protein depletion is a secondary event in the development of insulin resistance in this model of hyperglycemia/hyperinsulinemia; and 3) depletion of cellular IRS in adipose tissue may be a consequence rather than a cause of insulin resistance and hyperinsulinemia in type 2 diabetes.

Regional differences of insulin action in adipose tissue: insights from in vivo and in vitro studies

Adipose tissue is now recognized to have a multitude of functions that are of importance in the regulation of energy balance and substrate metabolism. Different hormones, in particular insulin and catecholamines, govern the storage and utilization of energy in the triglyceride depots. In addition, adipocytes produce several different substances with endocrine or paracrine functions, which regulate the overall energetic homeostasis. With excess energy storage, obesity develops, leading to increased risk for type 2 diabetes and cardiovascular disease. The distribution of body fat appears to be even more important than the total amount of fat. Abdominal and, in particular, visceral adiposity is strongly linked to insulin resistance, type 2 diabetes, hypertension and dyslipidaemia, leading to increased risk of cardiovascular disease. The adverse metabolic impact of visceral fat has been attributed to distinct biological properties of adipocytes in this depot compared with other adipose tissue depots. Indeed, regional variations in the metabolic activity of fat cells have been observed. Furthermore, expression studies aiming at defining the unique biological properties of adipose tissues from distinct anatomical sites have identified depot-related differences in the protein content of fat-produced molecules. In this review we wish to summarize important results from the literature and also some recent data from our own work. The main scope is to describe the biological functions of adipose tissue, and to focus on metabolic, hormonal, and signalling differences between fat depots.

Evaluation of simple non-invasive techniques for assessment of lower extremity arterial disease

OBJECTIVE

To evaluate the reproducibility and precision of three, simple, non-invasive methods to measure blood pressure (BP) in the lower extremities by comparing reproducibility and sensitivity in finding abnormally low BP between ankle blood pressure (ABP) and toe blood pressure (TBP), by studying the concordance between TBP in toe 1 and 2 and evaluating the pole-pox method in patients with diabetes and lower extremity arterial disease (LEAD).

SUBJECTS AND METHODS

The BP was measured twice, 1 week apart, in arms and legs in 13 controls and 12 patients with diabetes. ABP was assessed by using a Doppler pen for pulse registration. TBP was obtained by using a small cuff and a pulse oximetry sensor at toe 1 and 2. In eleven patients with diabetes and previously known LEAD ABP was obtained through the pole-pox method.

RESULTS

No significant difference in reproducibility between absolute BPs and indices (coefficients of variation <9%) was found. A non-significant improvement with 4-8% in the sensitivity in detecting LEAD was seen when BP indices were used instead of absolute BP. A significant correlation in the variation over time for systemic and TBP (r = 0.34, P = 0.015) and a strong correlation was found between TBP measured at toe 1 and 2, respectively (r = 0.99, P < 0.001) was found. TBP measured with pole-pox method were significantly correlated with measurements made by the ordinary cuff technique (r = 0.75, P < 0.001).

CONCLUSIONS

The use of TBP and ABP indices instead of absolute BP does not improve the reproducibility but may improve the sensitivity with respect to detection of LEAD, especially in patients with diabetes. The pole-pox method may be used as an alternative screening method in patients with diabetes and LEAD.

The risk of venous thromboembolism is markedly elevated in patients with diabetes

AIMS/HYPOTHESIS

Diabetes mellitus is associated with several changes in coagulation and fibrinolysis that may lead to a thrombogenic propensity. However, it is not known whether these perturbations actually cause increased risk of venous thromboembolism.

METHODS

In a retrospective population-based study we evaluated the medical records of all 302 adult patients who were admitted to the Umea University Hospital with verified deep vein thrombosis or pulmonary embolism during the years 1997 to 1999. The patients were classified as diabetic (n=56) and non-diabetic (n=246) according to clinical information. The total number of diagnosed diabetic patients in different age groups in the catchment area was obtained from computerised registries in the primary health care centres and the Umea University Hospital, and data on the background population were collected from the Swedish population registry.

RESULTS

The annual incidence rate of venous thromboembolism among diabetic patients in the population was 432 per 100,000 individuals (95% CI 375-496). In non-diabetic individuals it was 78 (95% CI 68-88). The age-adjusted incidence rate among the diabetic population was 274 (95% CI 262-286). The annual incidence rate of venous thromboembolism was elevated in type 1 and type 2 diabetic patients and the incidence rates were 704 (95% CI 314-1,566) and 412 (95% CI 312-544) respectively. The overall standardised morbidity ratio was 2.27 (95% CI 1.75-2.95), i.e. diabetic patients were more prone to venous thromboembolism after adjustment for age differences.

CONCLUSIONS/INTERPRETATION

These results suggest that the age-adjusted risk for venous thromboembolism is more than two-fold higher among diabetic patients than in the non-diabetic background population.

Short-term effects of repetitive arm work and dynamic exercise on glucose metabolism and insulin sensitivity

AIM

To determine whether repetitive arm work, with a large component of static muscle contraction alters glucose metabolism and insulin sensitivity.

METHOD

Euglycemic clamps (2 h) were started in ten healthy individuals 15 min after 37 min periods of: (1) repetitive arm work in a simulated occupational setting; (2) dynamic concentric exercise on a cycle ergometer at 60% of VO(2max) and (3) a resting regime as a control. During the experimental periods, blood samples were collected, blood pressure was measured repeatedly and electrocardiogram (ECG) was recorded continuously. During the clamps, euglycemia was maintained at 5 mmol l(-1) and insulin was infused at 56 mU m(-2) min(-1) for 120 min.

RESULTS

The insulin-mediated glucose disposal rate (M-value) for the steady-state period (60-120 min) of the clamp, tended to be lower following arm work than for both cycling and resting regimes. When dividing the steady-state period into 20-min intervals, the insulin sensitivity index (ISI) was significantly lower for arm work compared with the resting control situation between 60-80 min (P = 0.04) and 80-100 min (P = 0.01), respectively. Catecholamines increased significantly for arm work and cycling compared with resting regime. Data from heart rate variability (HRV) measurements indicated significant sympathetic activation during repetitive arm work.

CONCLUSION

The results indicate that repetitive arm work might acutely promote insulin resistance, whereas no such effect on insulin resistance was produced by dynamic concentric exercise.

Tissue-specific regulation of lipoprotein lipase in humans: effects of fasting

BACKGROUND

We have previously reported that the activity of lipoprotein lipase (LPL) measured in postheparin plasma from humans fasted for 30 h is increased relative to the fed state. This is in contrast to laboratory animals, where the strong down-regulation of LPL in their adipose tissue on fasting is reflected in decreased levels of LPL activity in postheparin plasma.

MATERIALS AND METHODS

To search for the tissue source of the increase in LPL activity on fasting of humans, young, healthy subjects were fasted for 10, 20 or 30 h, and LPL was measured in plasma (pre- and postheparin) and in biopsies from subcutaneous adipose tissue (abdominal) and from a skeletal muscle (tibialis anterior). Both LPL activity and LPL protein mass were measured in the tissue homogenates. Values after fasting were compared with values from postprandial samples obtained 2 h after a meal.

RESULTS

Fasting for up to 30 h did not alter LPL activity in basal plasma (preheparin). LPL activity in postheparin plasma remained unchanged after 10 and 20 h of fasting, but was increased by 50% after 30 h (P < 0.05). Ten hours of fasting caused a 25% (P < 0.05) decrease in LPL activity in subcutaneous adipose tissue, while LPL activity in skeletal muscle remained unchanged. After 30 h of fasting, both LPL activity and mass had decreased by approximately 50% (P < 0.05) in adipose tissue, but had increased by approximately 100% (P < 0.05) in muscle.

CONCLUSIONS

The increase in postheparin plasma LPL activity after 30 h of total food deprivation of healthy human subjects seemed to reflect an increased activity and mass of LPL in skeletal muscle.

Sustained effects of pioglitazone vs. glibenclamide on insulin sensitivity, glycaemic control, and lipid profiles in patients with Type 2 diabetes

AIMS

This study compared the effects of 52 weeks' treatment with pioglitazone, a thiazolidinedione that reduces insulin resistance, and glibenclamide, on insulin sensitivity, glycaemic control, and lipids in patients with Type 2 diabetes.

METHODS

Patients with Type 2 diabetes were randomized to receive either pioglitazone (initially 30 mg QD, n = 91) or micronized glibenclamide (initially 1.75 mg QD, n = 109) as monotherapy. Doses were titrated (to 45 mg for pioglitazone and 10.5 mg for glibenclamide) to achieve glycaemic targets during the next 12 weeks: fasting blood glucose of < or = 7 mmol/l and 1-h postprandial blood glucose of < or = 10 mmol/l. Patients were maintained on the titrated dose for 40 weeks.

RESULTS

Pioglitazone significantly increased insulin sensitivity compared with glibenclamide, as assessed by homeostasis model assessment (17.0% vs. -13.0%; P < 0.001), quantitative insulin sensitivity check index (0.011 vs. -0.007; P < 0.001) and fasting serum insulin (-1.3 pmol/l vs. 23.8 pmol/l; P = 0.007). The glibenclamide group had significantly lower HbA1c than the pioglitazone group after 12 weeks of therapy (7.8% vs. 8.3%, P = 0.015), but significantly higher HbA1c after 52 weeks of therapy (7.8% vs. 7.2%, P = 0.001). Pioglitazone significantly (vs. glibenclamide) increased mean HDL-C (P < 0.001), decreased mean triglycerides (P = 0.019), and decreased mean atherogenic index of plasma (AIP; P = 0.001) and mean total cholesterol/HDL-C (P = 0.004), without significantly elevating mean total cholesterol or mean LDL-C compared with glibenclamide. CONCLUSIONS These data suggest that the effects of pioglitazone are more sustained than those of glibenclamide for improving insulin sensitivity in patients with Type 2 diabetes, and that 52 weeks' treatment with pioglitazone has favourable effects on glycaemic control and lipoprotein profile.

Glucocorticoids down-regulate glucose uptake capacity and insulin-signaling proteins in omental but not subcutaneous human adipocytes

Visceral adiposity is associated with insulin resistance and type 2 diabetes. This study explores the metabolic differences between s.c. and visceral fat depots with respect to effects in vitro of glucocorticoids and insulin on glucose uptake. Adipocytes from human s.c. and omental fat depots were obtained during abdominal surgery in 18 nondiabetic subjects. Cells were isolated, and metabolic studies were performed directly after the biopsies and after a culture period of 24 h with or without dexamethasone. After washing, basal and insulin-stimulated [14C]glucose uptake as well as cellular content of insulin signaling proteins and glucose transporter 4 (GLUT4) was assessed. Omental adipocytes had an approximately 2-fold higher rate of insulin-stimulated glucose uptake compared with s.c. adipocytes (P < 0.01). Dexamethasone treatment markedly inhibited (by approximately 50%; P < 0.05) both basal and insulin-stimulated glucose uptake in omental adipocytes but had no consistent effect in s.c. adipocytes. The cellular content of insulin receptor substrate 1 and phosphatidylinositol 3-kinase did not differ significantly between the depots, but the expression of protein kinase B (PKB) tended to be increased in omental compared with s.c. adipocytes (P = 0.09). Dexamethasone treatment decreased the expression of insulin receptor substrate 1 (by approximately 40%; P < 0.05) and PKB (by approximately 20%; P < 0.05) in omental but not in s.c. adipocytes. In contrast, dexamethasone pretreatment had no effect on insulin-stimulated Ser473 phosphorylation of PKB. GLUT4 expression was approximately 4-fold higher in omental than s.c. adipocytes (P < 0.05). Dexamethasone treatment did not alter the expression of GLUT4. In conclusion, human omental adipocytes display approximately 2-fold higher glucose uptake rate compared with s.c. adipocytes, and this could be explained by a higher GLUT4 expression. A marked suppression is exerted by glucocorticoids on glucose uptake and on the expression of insulin signaling proteins in omental but not in s.c. adipocytes. These findings may be of relevance for the interaction between endogenous glucocorticoids and visceral fat in the development of insulin resistance.

Normal weight promotes remission and low number of islet antibodies prolong the duration of remission in Type 1 diabetes

AIM

To identify clinical, immunological and biochemical factors that predict remission, and its duration in a large cohort of young adults with Type 1 diabetes mellitus (DM).

METHODS

In Sweden, 362 patients (15-34 years), classified as Type 1 DM were included in a prospective, nation-wide population-based study. All patients were followed at local hospitals for examination of HbA(1c) and insulin dosage over a median period after diagnosis of 5 years. Duration of remission, defined as an insulin maintenance dose </= 0.3 U/kg/24 h and HbA(1c) within the normal range, was analysed in relation to characteristics at diagnosis.

RESULTS

Remissions were seen in 43% of the patients with a median duration of 8 months (range 1-73). Sixteen per cent had a remission with a duration > 12 months. Among patients with antibodies (ab(+)), bivariate analysis suggested that adult age, absence of low BMI, high plasma C-peptide concentrations, lack of ketonuria or ketoacidosis at diagnosis and low insulin dose at discharge from hospital were associated with a high possibility of achieving remission. Multiple regression showed that normal weight (BMI of 20-24.9 kg/m(2)) was the only factor that remained significant for the possibility of entering remission. In survival analysis among ab(+) remitters, a low number of islet antibodies, one or two instead of three or four, were associated with a long duration of remissions.

CONCLUSION

In islet antibody-positive Type 1 DM, normal body weight was the strongest factor for entering remission, whilst a low number of islet antibodies was of importance for the duration.

Early glycemic control, age at onset, and development of microvascular complications in childhood-onset type 1 diabetes: a population-based study in northern Sweden

OBJECTIVE

The aim of this work was to study the impact of glycemic control (HbA(1c)) early in disease and age at onset on the occurrence of incipient diabetic nephropathy (MA) and background retinopathy (RP) in childhood-onset type 1 diabetes.

RESEARCH DESIGN AND METHODS

All children, diagnosed at 0-14 years in a geographically defined area in northern Sweden between 1981 and 1992, were identified using the Swedish Childhood Diabetes Registry. From 1981, a nationwide childhood diabetes care program was implemented recommending intensified insulin treatment. HbA(1c) and urinary albumin excretion were analyzed, and fundus photography was performed regularly. Retrospective data on all 94 patients were retrieved from medical records and laboratory reports.

RESULTS

During the follow-up period, with a mean duration of 12 +/- 4 years (range 5-19), 17 patients (18%) developed MA, 45 patients (48%) developed RP, and 52% had either or both complications. A Cox proportional hazard regression, modeling duration to occurrence of MA or RP, showed that glycemic control (reflected by mean HbA(1c)) during the follow-up was significantly associated with both MA and RP when adjusted for sex, birth weight, age at onset, and tobacco use as potential confounders. Mean HbA(1c) during the first 5 years of diabetes was a near-significant determinant for development of MA (hazard ratio 1.41, P = 0.083) and a significant determinant of RP (1.32, P = 0.036). The age at onset of diabetes significantly influenced the risk of developing RP (1.11, P = 0.021). Thus, in a Kaplan-Meier analysis, onset of diabetes before the age of 5 years, compared with the age-groups 5-11 and >11 years, showed a longer time to occurrence of RP (P = 0.015), but no clear tendency was seen for MA, perhaps due to lower statistical power.

CONCLUSIONS

Despite modern insulin treatment, >50% of patients with childhood-onset type 1 diabetes developed detectable diabetes complications after approximately 12 years of diabetes. Inadequate glycemic control, also during the first 5 years of diabetes, seems to accelerate time to occurrence, whereas a young age at onset of diabetes seems to prolong the time to development of microvascular complications.

No in vitro effects of fatty acids on glucose uptake, lipolysis or insulin signaling in rat adipocytes

Elevated plasma levels of free fatty acids (FFA) can produce insulin resistance in skeletal muscle tissue and liver and, together with alterations in beta-cell function, this has been referred to as lipotoxicity. This study explores the effects of FFAs on insulin action in rat adipocytes. Cells were incubated 4 or 24 h with or without an unsaturated FFA, oleate or a saturated FFA, palmitate (0.6 and 1.5 mM, respectively). After the culture period, cells were washed and insulin effects on glucose uptake and lipolysis as well as cellular content of insulin signaling proteins (IRS-1, PI3-kinase, PKB and phosphorylated PKB) and the insulin regulated glucose transporter GLUT4 were measured. No significant differences were found in basal or insulin-stimulated glucose uptake in FFA-treated cells compared to control cells, regardless of fatty acid concentration or incubation period. Moreover, there were no significant alterations in the expression of IRS-1, PI3-kinase, PKB and GLUT4 following FFA exposure. Insulin's ability to stimulate PKB phosphorylation was also left intact. Nor did we find any alterations following FFA exposure in basal or cAMP-stimulated lipolysis or in the ability of insulin to inhibit lipolysis. The results indicate that oleate or palmitate does not directly influence insulin action to stimulate glucose uptake and inhibit lipolysis in rat fat cells. Thus, lipotoxicity does not seem to occur in the fat tissue itself.

Islet antibodies and remaining beta-cell function 8 years after diagnosis of diabetes in young adults: a prospective follow-up of the nationwide Diabetes Incidence Study in Sweden

OBJECTIVES

To establish the prevalence of remaining beta-cell function 8 years after diagnosis of diabetes in young adults and relate the findings to islet antibodies at diagnosis and 8 years later.

DESIGN

Population-based cohort study.

SETTING

Nationwide from all Departments of Medicine and Endocrinology in Sweden.

SUBJECTS

A total of 312 young (15-34 years old) adults diagnosed with diabetes during 1987-88.

MAIN OUTCOME MEASURE

Plasma connecting peptide (C-peptide) 8 years after diagnosis. Preserved beta-cell function was defined as measurable C-peptide levels. Three islet antibodies - cytoplasmic islet cell antibodies (ICA), glutamic acid decarboxylase antibodies and tyrosine phosphatase antibodies - were measured.

RESULTS

Amongst 269 islet antibody positives (ab+) at diagnosis, preserved beta-cell function was found in 16% (42/269) 8 years later and these patients had a higher body mass index (median 22.7 and 20.5 kg m-2, respectively; P = 0.0003), an increased frequency of one islet antibody (50 and 24%, respectively; P = 0.001), and a lower prevalence of ICA (55 and 6%, respectively; P = 0.007) at diagnosis compared with ab+ without remaining beta-cell function. Amongst the 241 patients without detectable beta-cell function at follow-up, 14 lacked islet antibodies, both at diagnosis and at follow-up.

CONCLUSIONS

Sixteen per cent of patients with autoimmune type 1 diabetes had remaining beta-cell function 8 years after diagnosis whereas 5.8% with beta-cell failure lacked islet autoimmunity, both at diagnosis and at follow-up.

Signs of nephropathy may occur early in young adults with diabetes despite modern diabetes management: results from the nationwide population-based Diabetes Incidence Study in Sweden (DISS)

OBJECTIVE

To estimate the occurrence of early-onset renal involvement in a nationwide population-based cohort of young adults with diabetes in Sweden and relate the findings to glycemic control, type of diabetes, sex, smoking, and blood pressure.

RESEARCH DESIGN AND METHODS

The Diabetes Incidence Study in Sweden aims to register all incident cases of diabetes in the age-group 15-34 years. In 1987-1988, 806 patients were reported and invited to participate in a follow-up study focusing on microvascular complications. Of them, 469 subjects participated. The assessment was based on questionnaires (n = 469), blood samples (n = 424), urine samples (n = 251) and, when appropriate, medical records (n = 186).

RESULTS

During the follow-up time, median 9 years (range 6-12), 31 of 469 patients (6.6%) with incipient or overt diabetic nephropathy (i.e., micro- or macroalbuminuria) were found, 24 of 426 (5.6%) in type 1 and 7 of 43 (16%) in type 2 diabetic subjects (P = 0.016). Additionally, 24 of 31 patients (77%) had microalbuminuria and 7 (23%) had macroalbuminuria, which mainly occurred in patients with type 2 diabetes. In a Cox regression analysis, high mean HbA(1c) during the follow-up period and high blood pressure at follow-up increased the risk of developing signs of nephropathy (P = 0.020 and P = 0.003, respectively). Compared with patients with type 1 diabetes, those with type 2 diabetes tended to have an increased risk of renal involvement (P = 0.054) when adjusting for sex, tobacco use, glycemic control, and blood pressure.

CONCLUSIONS

Despite modern treatment and self-monitoring of blood glucose, young adult patients with diabetes may still develop renal involvement during the first 10 years of diabetes duration. Inadequate HbA(1c), high blood pressure, and type 2 diabetes appear to be risk markers for early occurrence of diabetic nephropathy.

Effect of dalteparin on healing of chronic foot ulcers in diabetic patients with peripheral arterial occlusive disease: a prospective, randomized, double-blind, placebo-controlled study

OBJECTIVE

Chronic foot ulcers are a common, severe, and expensive complication threatening life and limb in patients with diabetes. The aim of the present study was to investigate the effect of dalteparin on ulcer outcome in patients with diabetes, peripheral arterial occlusive disease, and chronic foot ulcers.

RESEARCH DESIGN AND METHODS

A total of 87 patients were investigated in a prospective, randomized, double-blind, placebo-controlled trial. Participants were randomized to treatment with subcutaneous injection of 5000 units dalteparin (Fragmin, Pharmacia Corporation; n = 44) or an equivalent volume of physiological saline (n = 43) once daily until ulcer healing or for a maximum of 6 months. Ulcer outcome was investigated by evaluating the number of patients 1). who healed with intact skin; 2). in whom the study ulcer was improved, unchanged, or impaired; or 3). who were amputated above or below the ankle level, as compared with control subjects.

RESULTS

Two patients, one on dalteparin and one on placebo, dropped out of the study. Ulcer outcome was significantly better (P = 0.042, two-sided chi(2) test for trend) in the dalteparin group (n = 43) compared with the placebo group (n = 42). A total of 29 patients healed with intact skin (n = 14) or decreased the ulcer area >or=50% (n = 15) in the dalteparin group compared with 20 (n = 9 and 11, respectively) in the placebo group. Five patients in each group showed impaired ulcer healing, i.e., the ulcer area increased >or=50%. Two patients in the dalteparin group were amputated compared with eight in the placebo group. Time to healing with intact skin was 17 +/- 8 weeks in the dalteparin group compared with 16 +/- 7 weeks in placebo group (NS).

CONCLUSIONS

The results of the present study indicate that dalteparin improves the outcome of chronic foot ulcers in diabetic patients with peripheral arterial occlusive disease.

Increasing body mass index at diagnosis of diabetes in young adult people during 1983-1999 in the Diabetes Incidence Study in Sweden (DISS)

OBJECTIVE

To study trends in body mass index (BMI) at diagnosis of diabetes in all young Swedish adults in the age range of 15-34 years registered in a nation-based registry.

DESIGN

The BMI was assessed at diagnosis in diabetic patients 15-34 years of age at diagnosis, for a period of 17 years (1983-1999). Islet cell antibodies (ICA) were measured during three periods (1987-1988, 1992-1993 and 1998-1999).

SETTING

A nationwide study (Diabetes Incidence Study in Sweden).

SUBJECTS

A total of 4727 type 1 and 1083 type 2 diabetic patients.

MAIN OUTCOME MEASURES

Incidence-year specific BMI adjusted for age, gender and time of diagnosis (month).

RESULTS

Body mass index at diagnosis increased significantly both in type 1 (21.4 +/- 3.6 to 22.5 +/- 4.0; P < 0.0001) and in type 2 (27.4 +/- 6.8 to 32.0 +/- 6.0; P < 0.0001) diabetic patients, also when adjusted for age, gender and month of diagnosis. A similar significant increase in BMI was found in type 1 diabetic patients and in type 2 diabetic patients in the periods 1987-1988, 1992-1993 and 1998-1999; years when ICA were assessed and considered in the classification of diabetes. Despite this increase in BMI, there was no increase in the incidence of diabetes in young-adult people in Sweden.

CONCLUSION

Body mass index at diagnosis of diabetes in subjects 15-34 years of age has substantially increased during 1983-1999 in Sweden when adjusted for age, gender and month of diagnosis.

Combined near-infrared spectroscopy and multifrequency bio-impedance investigation of skin alterations in diabetes patients based on multivariate analyses

A group of 34 diabetic men, with different degrees of diabetes complications, including skin changes, were studied by near-infrared (NIR) spectroscopy and total body multi-frequency bio-impedance analyses (MFBIA-body). Skin reflectance spectra were measured with a fibre-optic probe in four locations (sites): hand, arm, leg and foot. As control subjects, a group of 23 healthy males were also measured. A combined multivariate analysis of the two types of spectrum was performed. It was concluded that the NIR method has the potential to detect diabetes-related skin conditions and also that the combination of the two techniques provides a higher potential for classification and discrimination of the skin conditions, with correct classification increasing from 63% to 85%.

Does the autonomic nervous system play a role in the development of insulin resistance? A study on heart rate variability in first-degree relatives of Type 2 diabetes patients and control subjects

AIMS

To investigate dysregulation of the autonomic nervous system as a potential mechanism for early insulin resistance in the development of Type 2 diabetes.

METHODS

Thirteen healthy individuals with first-degree relatives with Type 2 diabetes (R) were compared with 14 control subjects without family history of diabetes (C), matched for age, body mass index and sex. An oral glucose tolerance test and a hyperinsulinaemic euglycaemic clamp were performed. Analysis of heart rate variability during rest, controlled breathing, an orthostatic manoeuvre and a standardized physical stress (cold pressor test (CPT)), were used to evaluate the activity of the autonomic nervous system.

RESULTS

Fasting blood glucose, HbA1c and serum insulin were similar in the R and C groups. The M-value, reflecting insulin sensitivity, did not differ significantly between the groups. Total spectral power and high-frequency power were lower in R during controlled breathing (P = 0.05 and P = 0.07, respectively), otherwise there were no significant differences between R and C in heart rate variability. However, low-frequency (LF)/high-frequency (HF) spectral power ratio during CPT, reflecting sympathetic/parasympathetic balance, was negatively associated with insulin sensitivity (r = -0.53, P = 0.006). When all subjects were divided into two groups by the mean M-value, the low M-value group displayed an overall higher LF/HF ratio (P = 0.04). HF power was lower in the low M-value group during controlled breathing and CPT (P = 0.01 and P = 0.03, respectively).

CONCLUSION

An altered balance of the parasympathetic and sympathetic nervous activity, mainly explained by an attenuated parasympathetic activity, might contribute to the development of insulin resistance and Type 2 diabetes.

Metabolic effects of mealtime insulin lispro in comparison to glibenclamide in early type 2 diabetes

The efficacy and safety of the preprandial injection of insulin lispro was compared with the oral administration of glibenclamide in patients with early type 2 diabetes. In this open-label, multicenter study, 143 patients with a glucagon-stimulated increase in C-peptide of at least 0.4 nmol/L were randomized to receive preprandial insulin lispro (LP) or glibenclamide (GB) for 26 weeks. Seventy-five patients received LP (51 male/24 female; age 40 to 70 years, duration of diabetes 4.4 +/- 2.9 years) and 68 patients received GB (39 male/29 female; age 39 to 70 years; duration of diabetes 4.3 +/- 3.4 years). After 12 weeks, mean 90 minute blood glucose excursions were 0.9 +/- 1.0 mmol/L for LP and 1.8 +/- 1.2 mmol/L for GB (p < 0.0001). After 24 weeks, mean blood glucose excursions were 1.0 +/- 1.1 mmol/L for LP and 1.7 +/- 1.2 mmol/L for GB (p = 0.002). Body weight decreased slightly from 87.2 +/- 2.3 to 86.5 +/- 12.2 kg in the LP group and increased from 84.1 +/- 13.7 to 84.4 +/- 13.3 kg in the GB group. LP versus GB induced changes from baseline to endpoint in fasting C-peptide (nmol/L), proinsulin and insulin levels (pmol/L) were - 0.2 +/- 0.4 versus - 0.1 +/- 0.6 (p = 0.04), - 11.2 +/- 26.0 versus - 1.1 +/- 17.3 (p = 0.03), and - 27.8 +/- 147.4 versus + 32.6 +/- 286.2 (not significant), respectively. HbA 1c at baseline was 7.5 +/- 1.0 % for LP and 7.7 +/- 1.2 % for GB and did not change significantly in either group during the investigation. No significant difference was observed between the groups with respect to hypoglycemic episodes. Treatment with LP improved postprandial blood glucose control more than GB without increasing body weight or hypoglycemic episodes. In addition, use of LP was associated with a decrease in fasting C-peptide and proinsulin levels, suggesting a potential down regulation of endogenous insulin production and improved proinsulin processing efficiency.

In vitro reversal of hyperglycemia normalizes insulin action in fat cells from type 2 diabetes patients: is cellular insulin resistance caused by glucotoxicity in vivo?

Chronic hyperglycemia promotes the development of insulin resistance. The aim of this study was to investigate whether cellular insulin resistance is secondary to the diabetic state in human type 2 diabetes. Subcutaneous fat biopsies were taken from 3 age-, sex-, and body mass index (BMI)-matched groups with 10 subjects in each group: type 2 diabetes patients with either good (hemoglobin A(1c) [HbA(1c)] < 7%, G) or poor (HbA(1c) > 7.5%, P) metabolic control and healthy control subjects (C). Insulin action in vitro was studied by measurements of glucose uptake both directly after cell isolation and following a 24-hour incubation at a physiological glucose level (6 mmol/L). The relationship with insulin action in vivo was addressed by employing the euglycemic clamp technique. Freshly isolated fat cells from type 2 diabetes patients with poor metabolic control had approximately 55% lower maximal insulin response (1,000 microU/mL) on glucose uptake (P <.05) compared to C. Cells from P were more insulin-resistant (P <.05) than cells from G at a low (5 microU/mL) but not at a high (1,000 microU/mL) insulin concentration, suggesting insulin insensitivity. However, following 24 hours of incubation at physiological glucose levels, insulin resistance was completely reversed in the diabetes cells and no differences in insulin-stimulated glucose uptake were found among the 3 groups. Insulin sensitivity in vivo assessed with hyperinsulinemic, euglycemic clamp (M-value) was significantly associated with insulin action on glucose uptake in fresh adipocytes in vitro (r = 0.50, P <.01). Fasting blood glucose at the time of biopsy and HbA(1c), but not serum insulin, were negatively correlated to insulin's effect to stimulate glucose uptake in vitro (r = -0.36, P =.064 and r = - 0.41, P <.05, respectively) in all groups taken together. In the in vivo situation, fasting blood glucose, HbA(1c), and serum insulin were all negatively correlated to insulin sensitivity (M-value; r = -0.62, P<.001, r= -0.61, P<.001, and r = -0.56, p <.01, respectively). Cell size, waist-to-hip ration (WHR), and BMI correlated negatively with insulin's effect to stimulate glucose uptake both in vitro (r = -0.55, P <.01, r = -0.54, P <.01, and r = -0.43, P <.05, respectively) and in vivo (r = -0.43, P <.05, r = -0.50, P <.01, and r = -0.36, P <.05, respectively). Multiple regression analyses revealed that adipocyte cell size and WHR independently predicted insulin resistance in vitro. Furthermore, insulin sensitivity in vivo could be predicted by fasting blood glucose and serum insulin levels. We conclude that insulin resistance in fat cells from type 2 diabetes patients is fully reversible following incubation at physiological glucose concentrations. Thus, cellular insulin resistance may be mainly secondary to the hyperglycemic state in vivo.

Postprandial regulation of blood lipids and adipose tissue lipoprotein lipase in type 2 diabetes patients and healthy control subjects

BACKGROUND/AIM

In type 2 diabetes and other insulin-resistant conditions, postprandial hypertriglyceridaemia is an important metabolic perturbation. To further elucidate alterations in the clearance of triglyceride-rich lipoproteins in type 2 diabetes we focused on the nutritional regulation of adipose tissue lipoprotein lipase (LPL).

SUBJECTS AND METHODS

Eight subjects with type 2 diabetes and eight age-, sex- and body mass index (BMI)-matched control subjects underwent subcutaneous abdominal adipose tissue biopsies in the fasting state and 3.5 h following a standardized lipid-enriched meal. LPL activity and mass were measured in adipose tissue and also in plasma after an intravenous injection of heparin.

RESULTS

Postprandial, but not fasting, triglycerides were significantly higher in the diabetic subjects than in the control subjects (3.0+/-0.4 vs 2.0+/-0.2 mmol/l, P=0.028). Adipose tissue LPL activity was increased following the meal test by approximately 35-55% (P=0.021 and 0.004, respectively). There was no significant difference between the groups in this respect. The specific enzyme activity of LPL was not altered in the postprandial state. Fasting and postprandial adipose tissue LPL activity as well as post-heparin plasma LPL activity tended to be lower among the diabetes patients (NS). There was a significant and independent inverse association between insulin resistance (homeostasis model assessment insulin resistance (HOMA-IR) index) vs post-heparin plasma LPL activity and postprandial triglyceride levels, respectively. Adipose tissue LPL activity was related to insulin action in vitro on adipocyte glucose transport, but not to HOMA-IR.

CONCLUSION

Following food intake adipose tissue LPL activity is enhanced to a similar degree in patients with type 2 diabetes and in healthy control subjects matched for BMI, age and gender. If LPL dysregulation is involved in the postprandial hypertriglyceridaemia found in type 2 diabetes, it should occur in tissues other than subcutaneous fat.

The incidence of retinopathy 10 years after diagnosis in young adult people with diabetes: results from the nationwide population-based Diabetes Incidence Study in Sweden (DISS)

OBJECTIVE

To estimate the prevalence and severity of diabetic retinopathy (DR) 10 years after diagnosis in a nationwide population-based cohort study of young adult diabetic patients in Sweden.

RESEARCH DESIGN AND METHODS

The Diabetes Incidence Study in Sweden (DISS) aims to register all incident cases of diabetes aged 15-34 years in Sweden. In 1987-1988, 806 cases were reported, and 627 (78%) of them were followed up with regard to retinopathy 8-10 years later. The assessment was based on retinal photographs in most cases (86%).

RESULTS

Ten years after diagnosis, retinopathy was found in 247 patients (39%). The retinopathy was mild in 206 (33%), whereas 30 (4.8%) patients had moderate nonproliferative DR (NPDR) and 11 (1.8%) had proliferative DR (PDR). Patients with retinopathy had worse glycemic control during the years than patients without (HbA(1c) 8.1 +/- 1.5% and 6.8 +/- 1.2%, respectively; P < 0.001). In a Cox regression analysis, time to retinopathy was related to high HbA(1c) (P < 0.001) and high BMI (P = 0.001). Patients with type 2 diabetes had an increased prevalence of severe retinopathy (NPDR or PDR) compared with those with type 1 diabetes (14 of 93 [15%] versus no or mild 24 of 471 [5%], respectively; P < 0.001).

CONCLUSIONS

Despite modern diabetes management, 39% of young adult diabetic patients developed retinopathy within the first 10 years of the disease. Nevertheless, compared with the prevalence of retinopathy (63%), after a similar duration of diabetes before the Diabetes Control and Complications Trial, this prevalence was clearly lower. Current treatment aimed to achieve strict glycemic control has reduced the risk for developing retinopathy.

Evaluation of the new ADA and WHO criteria for classification of diabetes mellitus in young adult people (15-34 yrs) in the Diabetes Incidence Study in Sweden (DISS)

AIMS/HYPOTHESIS

We aimed to evaluate how an aetiology-based classification, as recommended in the ADA and WHO guidelines for classification of diabetes mellitus, matches clinical judgement in the Diabetes Incidence Study in Sweden (DISS), a study covering incident cases of diabetic patients aged 15 to 34 years.

METHODS

During a 1-year period (1998), blood samples were taken at diagnosis and 4 months (median) thereafter. Patients were classified according to clinical judgement by the reporting physicians and assessments of islet antibodies (ICA, GADA, and IA-2A) and plasma C-peptide.

RESULTS

In 1998, 422 patients were registered in DISS. Among the 313 patients participating in the follow-up, most with clinical Type 1 diabetes (185/218, 85%, 95% CI 79-89%) were islet antibody positive (ab+) at diagnosis. In addition, 14 out of 58 (24%, 14-37%) with clinical Type 2 diabetes and 21 out of 37 (57%, 40-73%) with unclassifiable diabetes were antibody positive at diagnosis. Further to this, 4 out of 33 (12%, 3-28%) were antibody negative with clinical Type 1 diabetes and 4 out of 44 (9%, 3-22%) with Type 2 had converted to antibody positive at follow-up. Among those who were constantly antibody negative, 10 out of 29 (34%, 18-54%) with clinical Type 1 and 1 out of 16 (6%, 0-30%) with unclassifiable diabetes had fasting plasma C-peptide concentrations below the normal range (<0.25 nmol/l) at follow-up.

CONCLUSION/INTERPRETATION

Most young adults with clinical Type 1 diabetes (199/218, 91%) had objective Type 1 (ab+ at diagnosis/follow-up and/or low fasting plasma C-peptide concentrations at follow-up), as did one third (18/58, 31%) with clinical Type 2 diabetes and more than half (22/37, 59%) with unclassifiable diabetes. About 10% of those who were antibody negative converted to antibody positive. Our study underlines that a classification considering aetiology is superior to clinical judgement.