Serum homocysteine levels are associated with the development of (micro)albuminuria: the Hoorn study

Microalbuminuria is a strong indicator of the risk of future cardiovascular disease and renal dysfunction. Slightly increased levels of homocysteine, an independent risk factor for atherothrombotic disease, have recently been found to be associated with the presence of (micro)albuminuria. However, it is unknown whether increased homocysteine levels precede the occurrence of (micro)albuminuria. Normoalbuminuric subjects (n=316, 66 with non-insulin-dependent diabetes mellitus [NIDDM]) of an age-stratified, sex-stratified, and glucose tolerance-stratified sample of a population-based cohort study were investigated at baseline and after a mean follow-up duration of 6.1 years. Development of (micro)albuminuria was defined as a mean albumin-to-creatinine ratio >2.0 mg/mmol at the follow-up examination. The cumulative incidence of (micro)albuminuria was 14. 0% (9.7 % to 18.3%) among nondiabetic subjects and 22.7% (12.9% to 32.5%) among NIDDM patients. Age-adjusted, sex-adjusted, and glucose tolerance status-adjusted logistic regression analyses showed development of (micro)albuminuria to be significantly associated with baseline homocysteine levels >19.0 micromol/L compared with homocysteine levels <9.1 micromol/L (odds ratio [OR] 5.1, 95% CI 1.1 to 23.0). For homocysteine levels of 9.1 to 14.0 micromol/L and 14.1 to 19.0 micromol/L, the values were OR 1.2 (95% CI 0.5 to 3.0) and OR 1.8 (95% CI 0.6 to 5.3), respectively. Additional adjustment for baseline insulin resistance, blood pressure, body mass index, presence of cardiovascular disease and retinopathy, current smoking, or estimates of glomerular filtration rate did not materially affect the results. Substituting homocysteine levels as a continuous variable for categories of homocysteine levels showed that a 5-micromol/L increase of the homocysteine level was associated with an increased risk of developing (micro)albuminuria (OR 1.38, 95% CI 0.97 to 1.95). Analyses performed in nondiabetic and diabetic subjects separately gave similar results among nondiabetic subjects. Among diabetic subjects, the association between homocysteine level and (micro)albuminuria could not be estimated, because there was an insufficient number of diabetic subjects with high homocysteine levels. Hyperhomocysteinemia is an independent determinant of the development of (micro)albuminuria among nondiabetic subjects, even after adjustment for estimates of glomerular filtration rate. We could neither confirm nor reject an association between homocysteine levels and the development of (micro)albuminuria among NIDDM subjects. These data suggest that homocysteine may play a pathophysiological role in the development of (micro)albuminuria.

Hyperhomocysteinemia is associated with the presence of retinopathy in type 2 diabetes mellitus: the Hoorn study

BACKGROUND

Retinopathy is the leading cause of blindness among patients with type 2 diabetes mellitus (DM). Hyperhomocysteinemia is a recently recognized risk factor for cardiovascular disease, independent of established risk factors.

OBJECTIVE

To study the association between the homocysteine level and retinopathy among subjects with and without DM.

METHODS

We studied an age-, sex-, and glucose tolerance-stratified random sample of a 50- to 75-year-old general white population in the Hoorn Study (N = 625). Retinal vascular changes (retinopathy) were assessed using ophthalmoscopy and/or fundus photography. Hyperhomocysteinemia was defined as a serum total homocysteine level greater than 16 micromol/L.

RESULTS

The prevalence of retinopathy was 9.8% (28/285) in subjects with normal glucose tolerance, 11.8% (20/169) in those with impaired glucose tolerance, 9.4% (10/106) in those with newly diagnosed type 2 DM, and 32.3% (21/65) in those with known type 2 DM. The prevalence of retinopathy was 10.3% (39/380) in subjects without hypertension and 16.3% (40/245) in subjects with hypertension; it was 12.0% (64/534) in subjects with a serum total homocysteine level of 16 micromol/L or less and 16.5% (15/91) in those with a serum total homocysteine level of more than 16 micromol/L. After stratification for DM and adjustment for age, sex, glycosylated hemoglobin, and hypertension, the odds ratio (95% confidence interval) for the relation between retinopathy and hyperhomocysteinemia was 0.97 (95% confidence interval, 0.42-2.82) in patients without DM and 3.44 (95% confidence interval, 1.13-10.42) in patients with DM (P =.08 for interaction).

CONCLUSION

The findings suggest that hyperhomocysteinemia may be a risk factor for retinopathy in patients with type 2 DM, but probably not in patients without DM. Arch Intern Med. 2000;160:2984-2990

Cardiovascular autonomic function is associated with (micro-)albuminuria in elderly Caucasian sujects with impaired glucose tolerance or type 2 diabetes: the Hoorn Study

OBJECTIVE

To determine whether impaired cardiovascular autonomic function correlates with albuminuria in an age-, sex-, and glucose tolerance-stratified sample of an elderly (50-75 years of age) Caucasian population and to determine whether this association is independent of other determinants of albuminuria.

RESEARCH DESIGN AND METHODS

We studied 536 subjects, 256 with normal glucose tolerance, 143 with impaired glucose tolerance (IGT), and 137 with type 2 diabetes. Microalbuminuria was defined as an albumin-to-creatinine ratio of > or =3.0 and < or =30 mg/mmol in an early morning urine sample. We used the deep-breathing test and the lying-to-standing test to obtain 4 measurements of cardiovascular autonomic function: 1) the heart rate (HR) variability during deep breathing, 2) the maximum HR within 15 s after standing up minus the mean HR before standing, 3) the maximum R-R interval between 15 and 30 s after standing up divided by the minimum R-R interval within 15 s after standing up, and 4) the systolic blood pressure in response to standing up. These 4 measurements were summarized in a single cardiovascular autonomic function score (CAFS).

RESULTS

A total of 38 subjects with microalbuminuria and 3 subjects with macroalbuminuria (>30 mg/mmol) were grouped as having albuminuria. In bivariate analyses, albuminuria was associated with age, waist-to-hip ratio, systolic and diastolic blood pressure, calculated glomerular filtration rate, and glucose tolerance status. The mean CAFS was higher in subjects with versus without albuminuria (7.5 vs. 5.9, P<0.001). Multiple logistical regression analyses revealed that the CAFS was independently associated with albuminuria in subjects with IGT or type 2 diabetes with an odds ratio (95% CI) of 1.19 (1.02-1.39) per point increase in the CAFS.

CONCLUSIONS

Impaired cardiovascular autonomic function is independently associated with (and thus a possible contributor to) the presence of albuminuria in subjects with IGT or type 2 diabetes.

Serum homocysteine is weakly associated with von Willebrand factor and soluble vascular cell adhesion molecule 1, but not with C-reactive protein in type 2 diabetic and non-diabetic subjects - The Hoorn Study

BACKGROUND

Hyperhomocysteinaemia may constitute an independent risk factor for cardiovascular disease, but it is still unclear by which pathophysiological mechanisms homocysteine (tHcy) may promote atherothrombosis. The aim of this study was firstly to examine whether tHcy is associated with endothelial dysfunction, increased adherence of leukocytes, and/or chronic low-grade inflammation, as estimated from plasma levels of von Willebrand factor (vWf), soluble vascular cell adhesion molecule 1 (sVCAM-1) and C-reactive protein (CRP), respectively. Secondly we investigated whether the presence of type 2 diabetes modifies these associations.

MATERIALS AND METHODS

Six hundred and ten subjects of a general population of middle-aged and elderly subjects, 170 of whom had type 2 diabetes, participated in this cross-sectional study. Linear regression analyses were used to study whether tHcy was associated with vWf, sVCAM-1 and CRP, and whether the presence of diabetes modified these associations.

RESULTS

After adjustment for confounders, tHcy was significantly but weakly associated with vWf (beta = 0.15, P = 0.05) and sVCAM-1 (beta = 0.082, P = 0.04). tHcy was not significantly associated with CRP (beta = 0.02, P = 0.91). The presence of diabetes did not significantly modify these associations.

CONCLUSIONS

This study provides evidence that tHcy is, at most, weakly associated with endothelial dysfunction as estimated from plasma vWf, and with leukocyte adhesion as estimated from plasma sVCAM-1. tHcy was not significantly associated with chronic low-grade inflammation as estimated from plasma CRP. Our data thus suggest that the link between tHcy and atherothrombosis cannot be explained by associations of tHcy with vWf, sVCAM-1 or CRP.

Diabetes Fear of Injecting and Self-Testing Questionnaire: a psychometric evaluation

OBJECTIVE

To study the psychometric properties of the Diabetes Fear of Injecting and Self-Testing Questionnaire (D-FISQ).

RESEARCH DESIGN AND METHODS

Two groups of patients were studied. Sample A consisted of 252 insulin-treated diabetes patients. Sample B incorporated 24 insulin-treated patients with high scores (> or = 95th percentile) on the D-FISQ. Test-retest correlations were assessed in both samples. Discriminant and convergent validity of the D-FISQ were assessed with questionnaires concerning fear of hypoglycemia, trait anxiety, and fear of bodily injury, illness, or death. To evaluate criterion-related validity, sample B participated in a behavioral avoidance test (BAT), in which the current level of avoidance of either self-injecting or self-testing was determined. Exploratory factor analysis (EFA) was performed to study whether 2 factors (fear of self-injecting [FSI] and fear of self-testing [FST]) could be detected.

RESULTS

Test-retest correlations ranged from 0.50 to 0.68 (P < 0.001). Correlations between D-FISQ and fear of hypoglycemia, trait anxiety, and fear of bodily injury, illness, or death ranged from 0.28 to 0.45 (P < 0.001). Patients who refused to do a BAT for self-injecting or self-testing had higher scores on FSI (P = 0.095) and FST (P = 0.01). EFA yielded 2 separate factors, FSI and FST.

CONCLUSIONS

Results from this study support reliability and validity of the D-FISQ, a self-report instrument that can be used for both clinical and research purposes.

Optimized basal-bolus therapy using a fixed mixture of 75% lispro and 25% NPL insulin in type 1 diabetes patients: no favorable effects on glycemic control, physiological responses to hypoglycemia, well-being, or treatment satisfaction

OBJECTIVE

To investigate the effects of a multiple injection regimen with a mixture of 75% lispro and 25% intermediate-acting insulin (lispro high mixture [HM]) before meals on glycemic control, physiological responses to hypoglycemia, well-being, and treatment satisfaction.

RESEARCH DESIGN AND METHODS

We studied 35 type 1 diabetes patients. After an 8- to 10-week lead-in period, patients were randomized to HM or human regular insulin therapy for 12-14 weeks. During the lead-in and treatment periods, HbA1c levels and hypoglycemic frequencies were measured, and patients completed the Well-Being Questionnaire and the Diabetes Treatment Satisfaction Questionnaire. In 19 patients, responses to hypoglycemia were tested during stepped euglycemic-hypoglycemic clamps.

RESULTS

HM treatment improved postprandial glycemia but had no effect on HbA1c, frequency of hypoglycemia, well-being, or treatment satisfaction. During experimental hypoglycemia, HM therapy was associated with a slightly lower total adrenaline response and a higher autonomic symptom threshold (i.e., the autonomic symptom response occurred at a lower blood glucose level) than human regular insulin therapy. We speculate that this effect resulted from an accumulation of insulin during the night.

CONCLUSIONS

Multiple injection therapy with HM rather than human regular insulin before meals does not offer advantages regarding glycemic control, frequency of hypoglycemia, well-being, or treatment satisfaction. In addition, this regimen causes an attenuation of the adrenaline and autonomic symptom responses to hypoglycemia.

Glucose tolerance and other determinants of cardiovascular autonomic function: the Hoorn Study

AIMS/HYPOTHESIS

Currently, three categories of measures are used to assess cardiovascular autonomic dysfunction: measures of the Ewing-test, measures of heart-rate variability, and measures of baroreflex sensitivity. We studied the determinants of these measures obtained from cardiovascular autonomic function tests in the Hoorn Study.

METHODS

The study group (n = 631) consisted of a glucose-tolerance-stratified sample from a 50- to 75-year-old group of people. Cardiac cycle duration (RR interval) and continuous finger arterial pressure were measured under three conditions: during (a) spontaneous breathing, (b) six deep breaths over one minute, and (c) an active change in position from lying to standing. From these readings, ten measures of autonomic function were assessed (three Ewing, six heart-rate variability and one baroreflex sensitivity). As possible determinants we considered age, sex, glucose tolerance, cardiovascular disease, use of anti-hypertensive drugs, anthropometric factors, metabolic factors and lifestyle factors.

RESULTS

Multivariate analysis showed that eight of ten cardiovascular autonomic function measures were most strongly associated with glucose tolerance. Furthermore, measures were moderately associated with age, sex, waist-to-hip ratio, use of anti-hypertensive drugs, and insulin. The measures were weakly associated with coronary artery disease but not with lipids. The strongest determinants seemed to differ between subjects with and without diabetes: in the non-diabetic subjects the most strongly associated were age and use of anti-hypertensive drugs and in subjects with diabetes, insulin. No consistent differences in association between the three categories of measures were observed.

CONCLUSION/INTERPRETATION

The strongest determinants of autonomic function were age, presence of diabetes and use of anti-hypertensive drugs.

Biological and behavioural determinants of the frequency of mild, biochemical hypoglycaemia in patients with Type 1 diabetes on multiple insulin injection therapy

BACKGROUND

Severe hypoglycaemic episodes are an important source of morbidity in people with Type 1 diabetes. The occurrence of severe hypoglycaemia is strongly related to the frequency of low blood glucose readings. The aim of this exploratory study was to identify determinants of the frequency of mild, biochemical hypoglycaemia in patients with Type 1 diabetes treated with multiple insulin injection therapy.

METHODS

We studied 31 patients with Type 1 diabetes in reasonable glycaemic control (HbA(1c)</=8.3%) during multiple injection therapy. The study had a prospective, observational design. We used standardised home blood glucose monitoring (HBGM) diaries to assess the frequency of hypoglycaemia (HBGM readings<3.5 mmol/L) over a period of 6 weeks. Potential determinants studied included biological factors, self-management factors (including weekly total physical activity and vigorous physical activity), psychological factors (including psychological distress) and mediating factors [average and standard deviation (SD) of the HBGM readings and self-reported hypoglycaemia awareness].

RESULTS

Determinants of mild hypoglycaemia frequency identified in univariate regression analyses were: SD and mean of HBGM (beta 0.6, p=0.001 and beta -0.6, p=0.001), diabetes duration (beta 0.5, p=0. 008) and self-reported hypoglycaemia unawareness (beta -0.5, p=0. 003). A trend was observed for performance of vigorous physical activities (beta 0.3, p=0.06) and external eating behaviour (beta -0. 3, p=0.1). These relations were confirmed in multivariate analyses.

CONCLUSIONS

Patients with Type 1 diabetes who have a high blood glucose variability and low average blood glucose concentration, diabetes of long duration, low body mass index, self-reported impaired awareness of hypoglycaemia and those participating in vigorous physical activities, specifically require interventions aimed at preventing hypoglycaemia.

Hyperhomocysteinemia increases risk of death, especially in type 2 diabetes : 5-year follow-up of the Hoorn Study

BACKGROUND

A high serum total homocysteine (tHcy) concentration is a risk factor for death, but the strength of the relation in patients with type 2 (non-insulin-dependent) diabetes mellitus compared with nondiabetic subjects is not known. A cross-sectional study suggested that the association between tHcy and cardiovascular disease is stronger in diabetic than in nondiabetic subjects. We therefore prospectively investigated the combined effect of hyperhomocysteinemia and type 2 diabetes on mortality.

METHODS AND RESULTS

Between October 1, 1989, and December 31, 1991, serum was saved from 2484 men and women, 50 to 75 years of age, who were randomly selected from the town of Hoorn, The Netherlands. Fasting serum tHcy concentration was measured in 171 subjects who died (cases; 76 of cardiovascular disease) and in a stratified random sample of 640 survivors (control subjects). Mortality risks were calculated over 5 years of follow-up by means of logistic regression. The prevalence of hyperhomocysteinemia (tHcy >14 micromol/L) was 25. 8%. After adjustment for major cardiovascular risk factors, serum albumin, and HbA(1c), the odds ratio (95% CI) for 5-year mortality was 1.56 (1.07 to 2.30) for hyperhomocysteinemia and 1.26 (1.02 to 1. 55) per 5-micromol/L increment of tHcy. The odds ratio for 5-year mortality for hyperhomocysteinemia was 1.34 (0.87 to 2.06) in nondiabetic subjects and 2.51 (1.07 to 5.91) in diabetic subjects (P=0.08 for interaction).

CONCLUSIONS

Hyperhomocysteinemia is related to 5-year mortality independent of other major risk factors and appears to be a stronger (1.9-fold) risk factor for mortality in type 2 diabetic patients than in nondiabetic subjects.

Hyperhomocysteinaemia is not associated with isolated crural arterial occlusive disease: The Hoorn Study

OBJECTIVES

Hyperhomocysteinaemia is an independent risk factor for peripheral arterial disease (PAD). The localization of peripheral arterial disease is clinically relevant, because proximal (aortoiliac and femoropopliteal) disease is associated with a particularly poor overall prognosis, whereas isolated distal (i.e. crural) disease is associated with a better overall prognosis. The aim of the study was to investigate whether the strength of the association between hyperhomocysteinaemia and peripheral arterial disease differs according to the localization of the anatomical obstruction.

DESIGN

Fasting serum total homocysteine (tHcy) was measured in an age-, sex- and glucose-tolerance stratified random sample (n = 631) of a 50- to 75-year-old general Caucasian population. History of a peripheral arterial reconstruction was recorded. Aortoiliac, femoropopliteal and crural arterial obstructions were registered by means of Doppler flow velocity curves.

RESULTS

The median serum tHcy level was 12.2 micromol L-1 (interquartile range: 10.0-15.3) in men and 10.7 micromol L-1 (interquartile range: 9.0-13.3) in women. The prevalences of aortoiliac, femoropopliteal and crural obstructions were 2.1%, 2.7% and 11.9%, respectively. After adjustment for age, sex, systolic blood pressure, current smoking, serum cholesterol and diabetes mellitus, the odds ratios (95% confidence interval) per 5 micromol L-1 tHcy increment were 1.41 (1.05-1.89) for aortoiliac, 1.03 (0. 70-1.52) for femoropopliteal and 0.82 (0.59-1.15) for crural obstructions. Finally, diabetes mellitus, HbA1c and current smoking were significantly associated with crural and femoropopliteal disease, whereas systolic blood pressure was significantly associated with aortoiliac obstructions.

CONCLUSIONS

The present study indicates that hyperhomocysteinaemia is associated with aortoiliac but not with isolated crural arterial occlusive disease.

Assessing impaired hypoglycemia awareness in type 1 diabetes: agreement of self-report but not of field study data with the autonomic symptom threshold during experimental hypoglycemia

OBJECTIVE

The aim of our study was to determine the agreement of two noninvasive methods, a self-report and a field study method, for the assessment of impaired hypoglycemia awareness with a gold standard criterion of hypoglycemia awareness, the autonomic symptom threshold during experimental hypoglycemia.

RESEARCH DESIGN AND METHODS

A total of 19 type 1 diabetic patients completed a standardized questionnaire to assess impaired hypoglycemia awareness and performed a hand-held computer (HHC) study to assess their recognition of hypoglycemic episodes occurring during 24 weeks. Patients subsequently underwent a stepped hypoglycemic clamp to study responses to standardized hypoglycemia. Diagnoses of impaired hypoglycemia awareness were based on the separate self-report questions, a composite self-report score, and three different cutoff levels for the percentage of accurately recognized hypoglycemic episodes during the field study Agreement of these noninvasive measures with the hypoglycemic clamp measure were tested by calculating kappa values, sensitivity, and specificity.

RESULTS

The composite self-report score agreed reasonably well with the hypoglycemic clamp measure (kappa 0.49, sensitivity 66.7%, and specificity 85.7%) and showed a better agreement than the separate self-report questions. The HHC criterion of impaired hypoglycemia awareness did not agree with the hypoglycemic clamp criterion at any of the cutoff levels tested.

CONCLUSIONS

The composite self-report tested in this study is a reasonably reliable assessment method for the diagnosis of impaired hypoglycemia awareness, using the physiological definition of an absence of autonomic symptoms at a blood glucose level of 3 mmol/l. In contrast, the recognition of hypoglycemic events in everyday life as measured using the HHC method is not related to the hypoglycemic clamp criterion.

Reduced second phase insulin secretion in carriers of a sulphonylurea receptor gene variant associating with Type II diabetes mellitus

AIMS/HYPOTHESIS

The sulphonylurea receptor is a subunit of the ATP-sensitive potassium channel in the pancreatic beta cell. Mutations at nt -3 of the splice acceptor site of exon 16 and a silent mutation in exon 18 of the gene for the sulphonylurea receptor (SUR1) associate with Type II (non-insulin-dependent) diabetes mellitus in several independent populations. We investigated whether these gene variants associate with changes in the pattern of glucose-stimulated insulin secretion.

METHODS

Subjects who had normal glucose tolerance (n = 67) and subjects with an impaired glucose tolerance (n = 94), originating from two independent studies, were included in the study. Beta-cell function and insulin sensitivity were assessed by the hyperglycaemic clamp.

RESULTS

Frequencies of the exon 16 -3t allele in the normal and impaired glucose tolerant groups were 46% and 44% respectively (p = NS). The more rare exon 18 T allele showed frequencies of 5 and 7% respectively (p = NS). We observed an approximately 25% reduced second-phase insulin secretion in carriers of the exon 16 -3t allele in both groups (p < 0.05). Estimates of insulin sensitivity did not show differences between carriers and non-carriers. The variant in exon 18 and the combined presence of variants in exon 16 and exon 18 were not associated with differences in insulin secretion or insulin sensitivity in our study groups.

CONCLUSION/INTERPRETATION

The diabetes associated exon 16 -3t variant of the SUR1 gene associates with a functional change of the beta cell as reflected by reduced second-phase insulin secretion in response to a standardized hyperglycaemia in normal and impaired glucose tolerant subjects.

Increased levels of soluble vascular cell adhesion molecule 1 are associated with risk of cardiovascular mortality in type 2 diabetes: the Hoorn study

Membrane-bound vascular cell adhesion molecule 1 (VCAM-1) allows the tethering and rolling of monocytes and lymphocytes as well as firm attachment and transendothelial migration of leukocytes. Soluble forms of VCAM (sVCAM-1) may serve as monitors of increased expression of membrane-bound VCAM-1 and thus may reflect progressive formation of atherosclerotic lesions. Levels of sVCAM-1 have been found to be increased among type 2 diabetic as compared with nondiabetic subjects. To study the association of plasma sVCAM-1 concentration and risk of cardiovascular and all-cause mortality among nondiabetic and diabetic subjects, we investigated an age-, sex-, and glucose-tolerance-stratified sample (n = 631) of a population-based cohort aged 50-75 years that was followed prospectively. Plasma levels of sVCAM-1 were determined in frozen -70 degrees C baseline samples. After 7.4 years (mean) of follow-up, 107 (17%) subjects had died (42 of cardiovascular causes). In the entire group, increased sVCAM-1 levels were significantly associated with increased risk of cardiovascular mortality (relative risks [RRs] per 100 ng/ml sVCAM-1 increase, 1.10 [1.05-1.15] after adjustment for age, sex, and glucose tolerance status). This RR was somewhat diminished by further adjustment for the presence of hypertension and cardiovascular disease; levels of total, HDL, and LDL cholesterol and homocysteine; the presence of microalbuminuria (a putative marker of endothelial dysfunction); levels of von Willebrand factor (a marker of endothelial dysfunction) and C-reactive protein (a marker of low-grade inflammation); and estimates of glomerular filtration rate. However, the RR remained statistically significant. The RR among type 2 diabetic subjects was 1.13 (1.07-1.20) per 100 ng/ml sVCAM-1 increase after adjustment for age and sex, which was somewhat higher but not significantly different from the RR in nondiabetic subjects (P value for interaction term, 0.12). Further adjustment for other risk factors gave similar results. In conclusion, levels of sVCAM-1 are independently associated with the risk of cardiovascular mortality in type 2 diabetic subjects and therefore might be useful for identifying subjects at increased cardiovascular risk. Increased plasma sVCAM-1 levels may reflect progressive formation of atherosclerotic lesions, or sVCAM-1 itself may have bioactive properties related to cardiovascular risk. Our data, however, argue against the hypotheses of sVCAM-1 levels simply being a marker of endothelial dysfunction, of low-grade inflammation, or of an impaired renal function.

Pravastatin compared to bezafibrate in the treatment of dyslipidemia in insulin-treated patients with type 2 diabetes mellitus

BACKGROUND

Both HMG-CoA reductase inhibitors and fibric acid derivates are used for the treatment of dyslipidemia in Type 2 diabetes patients. The aim of this study was to compare the lipid lowering effect of 40 mg pravastatin, a HMG-CoA reductase inhibitor, and 400 mg bezafibrate, a fibric acid derivate, on serum lipids, lipoproteins and lipoprotein composition in 45 (22 men and 23 women) dyslipidemic, insulin-treated Type 2 diabetes patients.

METHOD

The study used a double-blind, cross-over design.

RESULTS

Pravastatin treatment was more effective in reducing total cholesterol, LDL-cholesterol, LDL-triglycerides, LDL-ApoB and LDL/HDL-cholesterol ratio (all p<0.001 between groups) and total/HDL-cholesterol and ApoA1/LDL-ApoB ratios (both p<0.01) and always induced a decrease in LDL-cholesterol concentrations and LDL/HDL-cholesterol ratio irrespective of baseline triglyceride concentration. Bezafibrate was more effective in increasing HDL-cholesterol (p<0.01 between groups), ApoA1 lipoprotein and decreasing triglycerides (both p<0.001 between groups) but induced an increase in LDL-cholesterol concentration particularly in patients with baseline triglyceride concentrations exceeding 2.0 mmol/l. With bezafibrate treatment the LDL-cholesterol/LDL-ApoB ratio showed a tendency to rise, suggesting a change in the LDL particle composition to a less small and dense form, while pravastatin treatment induced a decrease in this ratio suggesting a change in the LDL particle to a more dense form. With pravastatin treatment a small rise in HbA(1c) was observed.

CONCLUSION

Pravastatin treatment is superior in lowering cholesterol-enriched lipoprotein subpopulations and improving cardiovascular risk factors. Bezafibrate is more effective in raising HDL-cholesterol and alters LDL particle composition to a more favorable form.

The well-being questionnaire: evidence for a three-factor structure with 12 items (W-BQ12)

BACKGROUND

The Well-being Questionnaire (W-BQ) has been designed to measure psychological well-being in people with a chronic somatic illness and is recommended by the World Health Organization for widespread use. However, studies into the factor structure of this instrument are still limited and their findings are inconsistent. This study aimed to investigate the factor structure of the Dutch version of the W-BQ.

METHODS

A cross-validation design was used. A total of 1472 people with diabetes completed the W-BQ and were randomly assigned to group A or B. In group A (N = 736), exploratory factor analyses were conducted. Group B (N = 736) was split up into four subgroups of male or female patients with type 1 or type 2 diabetes. In these subgroups, confirmatory factor analyses were employed to test the model(s) developed in group A and the two models described in the literature (four-factor model with 22 items and a three-factor model with 12 items).

RESULTS

Exploratory factor analyses yielded a three-factor model with 21 items (negative well-being, energy and positive well-being). In the subgroups of group B confirmatory factor analyses only accepted the three-factor model with 12 items. This factor solution was stable across gender, type of diabetes and level of education.

CONCLUSIONS

The best description of the factor structure of the Dutch translation of the W-BQ was given by a three-factor solution with 12 items (W-BQ12), measuring positive well-being (four items), negative well-being (four items) and energy (four items).

Change in common carotid artery diameter, distensibility and compliance in subjects with a recent history of impaired glucose tolerance: a 3-year follow-up study

OBJECTIVE

To assess the development of common carotid artery properties (diameter, distensibility and compliance) in a cohort of 140 subjects (mean age 65.8 years, SD 7.5 years) originally diagnosed as impaired glucose tolerant in a population-based study, and to explore determinants of changes observed.

DESIGN

An observational, longitudinal study over a 3-year-period.

METHODS

Vessel wall movement detector system based on ultrasonography, linear generalized estimating equations.

RESULTS

Carotid artery diameter rose from 6.87-7.02 mm (+ 2.2%, P<0.001). Distensibility decreased from 11.8 to 10.9 x 10-3 kPa-1 (-8.3%, P=0.009). Compliance decreased from 0.44-043 mm2 kPa-1 (P=0.17). Changes in blood pressure level were negatively associated with changes in distensibility and compliance. Baseline fasting glucose levels were positively associated with changes in diameter, while fasting insulin levels were negatively associated with changes in distensibility and compliance in men, but not in women.

CONCLUSIONS

In subjects with a recent history of impaired glucose tolerance, we observed an increase in carotid artery diameter and a decrease in distensibility. Change in blood pressure level and baseline fasting glucose and HbA1c levels were positively related to the increase in diameter. In men, but not in women, baseline fasting insulin levels were associated with an acceleration of these changes.

Major stressful life events in relation to prevalence of undetected type 2 diabetes: the Hoorn Study

OBJECTIVE

To test whether chronic psychological stress is positively associated 1) with the prevalence of type 2 diabetes; 2) with visceral adiposity; and to test whether 3) the relationship between stress and diabetes is mainly mediated by visceral adiposity

RESEARCH DESIGN AND METHODS

In a general Caucasian population aged 50-74 years without a history of diabetes (n = 2,262), the number of major stressful life events experienced during the past 5 years was assessed by self-report before the administration of an oral glucose tolerance test.

RESULTS

Diabetes was newly diagnosed among 5% of the subjects. The number of stressful events was positively associated with the prevalence of hitherto undetected diabetes. The highest quintile had a 1.6-fold (95% CI 1.0-2.6) increased probability of undetected diabetes compared with the remaining four quintiles (P<0.05 by logistical regression analysis adjusted for age and sex). This increased probability remained significant after additional adjustment for family history of diabetes, heavy alcohol consumption, physical activity, and low level of education. The number of stressful events was weakly positively associated with waist-to-hip ratio (WHR) (men, P<0.01; women, P = 0.05 by multiple regression analysis adjusted for age). The age- and sex-adjusted association between stress and diabetes was only marginally reduced by adding the WHR into the logistical regression model (odds ratio 1.5 [0.9-2.4]; P = 0.08).

CONCLUSIONS

These cross-sectional findings are partially consistent with Björntorp's theory that stressful life events, which indicate chronic psychological stress, are indeed associated with undetected type 2 diabetes and with visceral adiposity. However, in this white middle-aged population, visceral adiposity does not seem to be the main link between stress and diabetes.

'Numbness of the feet' is a poor indicator for polyneuropathy in Type 2 diabetic patients

AIMS

To identify neuropathic sensory symptoms associated with a clinical neurological examination (CNE) and to investigate whether these symptoms could be used as a diagnostic or screening tool for diabetic polyneuropathy in general practice.

METHODS

Five hundred and eighty-eight patients with Type 2 diabetes, recruited from 26 general practices in the Netherlands, underwent a CNE and completed a diabetes symptom checklist that included 10 items on neuropathic sensory symptoms. Linear regression analyses were performed to assess the association between neuropathic symptoms and CNE. Receiver operating characteristic (ROC) curves were created to assess the diagnostic properties of neuropathic symptoms.

RESULTS

In this population, with a mean age of 66.8 years, 32% were identified with diabetic polyneuropathy according to the CNE. Variables that showed the strongest association with CNE score were age (beta = 0.41), symptoms of sensory alteration (beta = 0.27), and the item 'numbness of the feet' (beta = 0.35) in particular. ROC curves showed that prediction of diabetic polyneuropathy from these symptoms was unsatisfying. The sensitivity and specificity of daily symptoms of 'numbness of the feet' were 28% and 93%, respectively, in patients <68 years, and 22% and 92%, respectively, in patients > or =68 years.

CONCLUSIONS

Identification of neuropathic sensory symptoms is not useful as a diagnostic or even a screening tool in the assessment of diabetic neuropathy in daily practice. Therefore, the results reported in this paper mandate an annual foot examination by the general practitioner.

Cytosolic triglycerides and oxidative stress in central obesity: the missing link between excessive atherosclerosis, endothelial dysfunction, and beta-cell failure?

Central obesity is increasingly recognized as a risk factor for atherosclerosis and type 2 diabetes mellitus. Here we present a hypothesis that may explain the excess atherosclerosis, endothelial dysfunction and progressive beta-cell failure. Central obesity is associated with increased cytosolic triglyceride stores in non-adipose tissues such as muscles, liver and pancreatic beta-cells. A high cytosolic triglyceride content is accompanied by elevated concentrations of cytosolic long-chain acyl-CoA esters, the metabolically active form of fatty acids. These esters inhibit mitochondrial adenine nucleotide translocators, resulting in an intramitochondrial ADP deficiency. In vitro, such ADP deficiency is a potent stimulator of mitochondrial oxygen free radical production, and we assume that this mechanism is also active in vivo. The decline of organ function with normal ageing is thought to be due, at least partly, to a continuous low-grade mitochondrial oxygen free radical production. In tissues containing increased cytosolic triglyceride stores this process will be accelerated. Tissues with a high-energy demand or poor free radical scavenging capacity, such as pancreatic beta-cells, are likely to be more susceptible to this process. This is how we explain their gradual dysfunctioning in central obesity. Likewise we propose that the enhanced production of oxygen free radicals in endothelial cells, or vascular smooth muscle cells, leads to the increased subendothelial oxidation of LDL and atherosclerosis, as well as to the endothelial dysfunction and microalbuminuria.

Similar 9-year mortality risks and reproducibility for the World Health Organization and American Diabetes Association glucose tolerance categories: the Hoorn Study

OBJECTIVE

To compare the risks of all-cause and cardiovascular disease (CVD) mortality in the American Diabetes Association (ADA) and World Health Organization (WHO) glucose tolerance categories after 9 years of follow-up in the Hoorn Study and to study the test-retest reproducibility of those categories.

RESEARCH DESIGN AND METHODS

In this population-based cohort study of 2,468 elderly men and women, subjects were classified according to both the WHO and the ADA criteria. Causes of death were extracted from the medical records. Age- and sex-adjusted relative risks were estimated by Cox's proportional hazards model. Reproducibility of the diagnostic criteria was assessed in a sample of 1,109 subjects with duplicate oral glucose tolerance tests.

RESULTS

Subjects with known diabetes had a four to five times higher risk of all-cause and CVD mortality compared with normal subjects (P<0.05). The relative risks of all-cause mortality were 1.67 (95% CI 1.09-2.57) and 1.56 (1.00-2.43) for newly diagnosed diabetic subjects according to the WHO and ADA criteria, respectively. The WHO and ADA criteria had similar levels of reproducibility The overall K was 0.59 (0.54-0.64) for WHO criteria and 0.61 (0.56-0.66) for ADA criteria. For the category of newly diagnosed diabetes according to WHO or ADA, the percentages of agreement for the second test compared with the first test were 77% (85/110) and 74% (74/100), respectively.

CONCLUSIONS

Both sets of diagnostic criteria identify criteria-specific diabetic subjects with an increased mortality risk compared with normal subjects, and the reproducibility of both criteria is similar.

von Willebrand factor, C-reactive protein, and 5-year mortality in diabetic and nondiabetic subjects: the Hoorn Study

Increased levels of von Willebrand factor (vWf) and C-reactive protein (CRP) predict cardiovascular mortality in selected populations. It is uncertain whether vWf and CRP predict mortality in a general population and whether vWf and CRP predict mortality through similar pathways. This study investigated the association of vWf and CRP with cardiovascular and all-cause mortality among diabetic and nondiabetic subjects. An age-, sex-, and glucose tolerance-stratified sample (n=631) of a population-based cohort aged 50 to 75 years was followed prospectively for 5 years. After 5 years of follow-up, 58 subjects had died (24 of cardiovascular causes). vWf (>1.56 IU/mL) and CRP (>2.84 mg/L) levels in the upper tertile were associated with, respectively, a 3- and 2-fold increase in cardiovascular mortality after adjustment for age, sex, and glucose tolerance status. Analyses in nondiabetic and diabetic subjects separately gave similar results. After further adjustment for hypertension, levels of HDL cholesterol and triglyceride, smoking habits, ischemic heart disease, and peripheral arterial disease, the relative risks (RRs) were 3.0 (95% CI 1.2 to 7.9) for vWf and 1.4 (95% CI 0.6 to 3.5) for CRP. When both vWf and CRP were included in the latter multivariate analysis, the RRs were 3.0 (95% CI 1.1 to 7.9) for vWf and 1.3 (95% CI 0.5 to 3.4) for CRP. The association between vWf and risk of cardiovascular mortality was independent of blood group (O versus non-O) and, moreover, similar among subjects with different blood groups. Repeating the analyses for all-cause mortality gave similar results for CRP. For vWf, the RR was 2.0 (95% CI 1.1 to 3.5) after adjustment for all other risk factors. Increased levels of vWf are independently associated with cardiovascular and all-cause mortality in both diabetic and nondiabetic subjects. The association between increased levels of CRP and cardiovascular mortality was partly explained by other risk factors. Mutual adjustment of vWf and CRP did not markedly change the results, favoring the hypothesis that vWf and CRP predict mortality through different pathways.

Hyperhomocysteinaemia is not related to risk of distal somatic polyneuropathy: the Hoorn Study

OBJECTIVE

Distal somatic polyneuropathy is a major contributing factor in the pathogenesis of chronic foot infections and ulcers, and may lead to lower limb amputations. Both metabolic and vascular abnormalities may contribute to the development of impaired nerve function. We therefore assessed the association between hyperhomocysteinaemia, a risk factor for cardiovascular disease, and polyneuropathy.

DESIGN, SETTING AND SUBJECTS

We studied an age-, sex- and glucose-tolerance-stratified random sample of a 50- to 75-year-old general Caucasian population in the Hoorn Study (N = 629). Any polyneuropathy (N = 95) was defined as the absence of at least two of the three following sensory modalities or reflexes of either foot: light touch sense, ankle reflex and vibration sensation. Definite polyneuropathy (N = 25) was present if, in addition, the vibration perception threshold of the right big toe was abnormal.

RESULTS

The prevalence of any polyneuropathy was 12.4% (33 of 266) in subjects with normal glucose tolerance (NGT), 12.6% (21 of 167) in those with impaired glucose tolerance (IGT), and 25.3% (41 of 162) in those with type 2 diabetes. The prevalence of definite polyneuropathy was 2.6% (7 of 266) in subjects with NGT, 2.4% (4 of 167) in those with IGT and 8.7% (14 of 161) in type 2 diabetic subjects. Polyneuropathy was associated with known risk factors such as diabetes, hyperglycaemia and body height. After adjustment for age, sex, HbA1c and hypertension, the odds ratio (95% CI) for any polyneuropathy per 5 micromol L-1 (about 1 SD) serum total homocysteine increment was 1.00 (0.72-1.39). After adjustment for age and sex, it was 0.62 (0.21-1.89) for definite polyneuropathy.

CONCLUSION

Although a weak relation (as judged from the confidence intervals) cannot be excluded, we conclude that hyperhomocysteinaemia is probably not related to risk of distal somatic polyneuropathy.

Triiodothyronine: a link between the insulin resistance syndrome and blood pressure?

OBJECTIVE

Overall obesity is associated with elevated serum triiodothyronine concentrations and insulin resistance. Oral triiodothyronine is known to induce hypertension in laboratory rats, while triiodothyronine also increases the expression of genes encoding for enzymes involved in the synthesis and secretion of insulin by pancreatic beta cells. We investigated the hypothesis that central obesity and insulin resistance are linked with an increased blood pressure and insulin production through elevated free serum triiodothyronine concentrations.

DESIGN

A cross-sectional study of 47 healthy euthyroid subjects (17 men, 30 women; 34 +/- 15 years, mean +/- SD).

METHODS

The waist:hip ratio was used as measure of central obesity, and insulin-stimulated glucose disposal during a hyperinsulinaemic euglycaemic clamp was used as measure of insulin sensitivity. Insulin production was calculated from the insulin clearance during the clamp and fasting insulin concentrations.

RESULTS

Free serum triiodothyronine concentrations correlated, independent of age and gender, positively with systolic and diastolic blood pressure, insulin production and fasting insulin. There was only a borderline significant correlation of free serum triiodothyronine with the waist-to-hip ratio, and no correlation with insulin sensitivity as assessed during the clamp. The correlations of free serum triiodothyronine with blood pressure, insulin production and fasting insulin were independent of the waist:hip ratio and insulin sensitivity.

CONCLUSION

Our hypothesis of free serum triiodothyronine as an intermediate factor in the insulin resistance syndrome is refuted by these data, but we identified free serum triiodothyronine concentrations as a new determinant of blood pressure, insulin production, and fasting insulin in healthy euthyroid subjects.