Urinary phthalate and DINCH metabolite concentrations and gradations of maternal glucose intolerance

BACKGROUND

Studies suggest a link between pregnancy phthalate exposures and gestational diabetes mellitus (GDM). Few studies have evaluated associations between phthalate biomarkers (individual or mixtures) with gradations of maternal glucose intolerance.

METHODS

In a subset of 606 women participating in LIFECODES pregnancy cohort, a combination of 50-gram 1-h non-fasting glucose load test (GLT) and 100-gram 3-h fasting oral glucose tolerance test was used to determine pregnancy glycemic status (median: 27 weeks gestation): normoglycemia (n = 136), impaired glucose tolerance (IGT) (n = 296), and GDM (n = 174). Nineteen metabolites of phthalates and their replacements were measured during each trimester. We used multivariable logistic regression models to evaluate associations between biomarkers (in quartiles) and maternal glycemic status (GDM v. normoglycemia and IGT v. normoglycemia), adjusting for potential confounders. We also used principal component analysis to evaluate associations jointly accounting for metabolites as chemical mixtures.

RESULTS

Higher 1st trimester mono-3-carboxypropyl phthalate (MCPP) was associated with decreased odds of GDM (Q4 v. Q1: 0.30; 95% CI: 0.13, 0.67) and IGT (Q4 v. Q1 OR: 0.37; 95% CI: 0.17, 0.79). Higher 2nd trimester mono-isobutyl phthalate (MiBP) was associated with increased IGT (Q4 v. Q1 OR: 2.07; 95% CI: 1.06, 4.07), and 2nd trimester mono-3-hydroxybutyl phthalate (MHBP) was non-monotonically associated with increased GDM (Q2 v. Q1 OR: 3.21; 95% CI: 1.54, 6.87). Mixture analyses showed similar associations (Q4 v. Q1 for 2nd trimester dibutyl phthalates metabotlites mixtures OR: 2.08; 95% CI: 1.04, 4.22).

CONCLUSION

Some phthalate biomarkershad trimester-specific associations with glycemic outcomes, with long and short term health implications.

Urinary C-peptide/creatinine ratio: A useful biomarker of insulin resistance and refined classification of type 2 diabetes mellitus

BACKGROUND

The urinary C-peptide/creatinine ratio (UCPCR) is low in patients with type 1 diabetes mellitus, but it has not been well characterized in patients with type 2 diabetes mellitus (T2DM). We aimed to measure the UCPCRs in patients with T2DM and explore the relationships among UCPCR, insulin resistance (IR), and chronic vascular complications of diabetes.

METHODS

A cross-sectional study was performed of 1299 Chinese hospitalized patients with T2DM. Binary logistic regression was used to evaluate the relationships between the chronic vascular complications of diabetes and UCPCR. K-means analysis was used to allocate participants to subgroups with five to six variables (age at diagnosis, body mass index [BMI], glycosylated hemoglobin, homoeostasis model assessment 2-estimated beta-cell function (HOMA2-B), and HOMA2-insulin resistance (HOMA2-IR), with or without UCPCR).

RESULTS

UCPCR positively correlated with HOMA2-IR (r = 0.448, P < .001). After adjustment for sex, age, duration of diabetes, and other cardiovascular risk factors, UCPCR was positively associated with diabetic kidney disease (DKD) (odds ratio [OR] = 1.198, 95% CI 1.019-1.408, P = .029) and coronary heart disease (CHD) (OR = 1.312, 95% CI 1.079-1.594, P = .006). When UCPCR was added, cluster analysis using the six variables identified five subgroups of T2DM, characterized by differing age at diagnosis, BMI, beta-cell function, IR, and prevalence of vascular complications.

CONCLUSIONS

UCPCR is positively associated with IR, DKD, and CHD and represents a promising biomarker that could refine the classification of T2DM.

Maternal urinary phthalate metabolites in relation to gestational diabetes and glucose intolerance during pregnancy

BACKGROUND

Phthalates are common plasticizer chemicals that have been linked to glucose intolerance in the general population, but there is only limited research on their association with gestational diabetes (GDM).

OBJECTIVE

We evaluated the association between 11 urinary phthalate metabolites and GDM, impaired glucose tolerance (IGT), and continuous blood glucose concentration during pregnancy in The Infant Development and Environment Study (TIDES). Based on prior study results, our primary analyses focused on monoethyl phthalate (MEP) in relation to our outcomes of interest.

STUDY DESIGN

We used multi-variable logistic regression to examine the odds of GDM and IGT in relation to an interquartile-range (IQR) increase in natural log (ln)-transformed, specific gravity (SG)-adjusted first trimester (T1) and average of T1 and third trimester (T3) ("T1T3avg") phthalate metabolite concentrations. We fit linear regression models to examine the percent change in blood glucose per IQR increase in ln-transformed, SG-adjusted T1 and T1T3avg phthalates. In sensitivity analyses, we examined interactions between exposure and race. We adjusted for maternal age, maternal body mass index, study center, race/ethnicity, parity, and gestational age at glucose testing.

RESULTS

In our sample of 705 pregnant women, we observed 60 cases of GDM, 90 cases of IGT, and an average GLT blood glucose of 113.6 ± 27.7 mg/dL. In our primary analysis, T1T3avg MEP was positively associated with GDM ([OR (95% CI) per IQR increase] T1T3avg MEP: 1.61 (1.10, 2.36)). In secondary analyses, most other phthalates were not found to be related to study outcomes, though some associations were noted. Sensitivity analyses indicated possible strong race-specific associations in Asians, though these results are based on a small sample size (n = 35).

CONCLUSION

In alignment with our a priori selection, we documented an association between T1T3avg MEP and GDM. Additional phthalate metabolites were also found to be linked to glucose intolerance, with possible stronger associations in certain racial/ethnic subgroups. Given the prevalence of phthalate exposures and the growing evidence of associations with metabolic outcomes, future studies should continue to examine this question in diverse cohorts of pregnant women, particularly in those who may be at higher risk for GDM and IGT.

Relationship between urine pH and abnormal glucose tolerance in a community-based study

AIMS/INTRODUCTION

The association between urine pH and abnormal glucose tolerance in men and women is unclear; therefore, we carried out a community-based, cross-sectional study to investigate sex-specific associations between these values, possible indicators of prediabetes and type 2 diabetes.

MATERIALS AND METHODS

We enrolled 4,945 Japanese individuals (2,490 men and 2,455 women), who had undergone annual health checkups. To investigate the relationship between low urine pH and abnormal glucose tolerance, participants were divided into three groups based on their fasting plasma glucose levels (<6.11 mmol/L, 6.11-6.99 mmol/L and ≥6.99 mmol/L), and three groups based on their glycated hemoglobin levels (≤44.3 mmol/mol, 44.3-47.5 mmol/mol and ≥47.5 mmol/mol). To examine the effects of urine pH on abnormal glucose tolerance, participants were categorized into five groups based on their urine pH (5.0, 5.5, 6.0, 6.5 and ≥7.0).

RESULTS

Multivariate analysis adjusted for age, body mass index, systolic blood pressure, triglycerides, high-density lipoprotein cholesterol, uric acid, creatinine and antidiabetic agent use showed significant associations between low urine pH and both high fasting plasma glucose and high glycated hemoglobin levels (P for trend = 0.0260, 0.0075) in men. Furthermore, after the same adjustments, prevalence rates of abnormal glucose tolerance (≥6.11 mmol/L and ≥6.99 mmol/L), increased significantly as urine pH levels decreased (P for trend = 0.0483, 0.0181) in men. In women, a similar trend was observed without a significant difference.

CONCLUSIONS

Low urine pH is significantly associated with abnormal glucose tolerance; therefore, measuring urine pH might prove useful for identifying patients at high risk for diabetes.

Effect of valsartan on kidney outcomes in people with impaired glucose tolerance

AIMS

To examine the effect of valsartan on kidney outcomes in patients with impaired glucose tolerance (IGT).

METHODS

In a double-blind randomized trial, 9306 patients with IGT were assigned to valsartan (160 mg daily) or placebo. The co-primary endpoints were the development of diabetes and two composite cardiovascular outcomes. Prespecified renal endpoints included: the composite of renal death, end-stage renal disease (ESRD) or doubling of serum creatinine; estimated glomerular filtration rate (eGFR) ≤30 mL/min/1.73 m² ; hospitalization for renal failure; and progression from normoalbuminuria to microalbuminuria, microalbuminuria to macroalbuminuria, and normoalbuminuria to macroalbuminuria. The median follow-up was 6.2 years.

RESULTS

Valsartan reduced the incidence of diabetes but not cardiovascular events. In the valsartan group, 25/4631 patients (0.5%), vs 26/4675 (0.6%) patients in the placebo group, developed ESRD or experienced doubling of serum creatinine (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.55-1.66; P  = .87). Few patients in either group developed an eGFR of ≤30 mL/min/1.73 m² or had a renal hospitalization. Fewer patients on valsartan (237/4084 [5.8%]) than on placebo (342/4092 [8.4%]) developed microalbuminuria (HR 0.68, 95% CI 0.57-0.80; P  < .0001), and fewer valsartan-treated patients developed macroalbuminuria. Overall, urinary albumin-to-creatinine ratio (UACR) was 11% lower with valsartan (95% CI 8-13; P  < .0001) and 9% lower (95% CI 6-11; P  < .0001) after adjusting for both glucose and blood pressure.

CONCLUSIONS

The effect of valsartan on UACR was not wholly explained by change in blood pressure or glucose. Valsartan reduced the incidence of microalbuminuria in IGT without increasing the incidence of hyperkalaemia or renal dysfunction compared with placebo.

Maternal arsenic exposure and gestational diabetes and glucose intolerance in the New Hampshire birth cohort study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major pregnancy complication with detrimental effects for both mothers and their children. Accumulating evidence has suggested a potential role for arsenic (As) exposure in the development of GDM, but current studies have not assessed As exposure from water, urine or toenail samples.

METHODS

We investigated the association between As exposure and risk of glucose intolerance and GDM among 1151 women enrolled in the New Hampshire Birth Cohort Study. Arsenic was measured in home well water and via biomarkers (i.e., maternal urine collected ~24-28 weeks gestation and toenail clippings collected 2 weeks postpartum).

RESULTS

A total of 105 (9.1 %) of women were diagnosed with glucose intolerance and 14 (1.2 %) of women were diagnosed with GDM. A total of 10.3 % of women had water As levels above 10 μg/L, with a mean As level of 4.2. Each 5 μg/L increase in As concentration in home well water was associated with a ~10 % increased odds of GDM (OR: 1.1, 95 % CI 1.0, 1.2). A positive and statistically significant association also was observed between toenail As and GDM (OR: 4.5, 95 % CI 1.2, 16.6), but not urinary arsenic (OR: 0.8, 95 % CI 0.3, 2.4). In a stratified analysis, the association between water As and GDM and glucose intolerance was largely limited to obese women (OR: 1.7, 95 % CI 1.0, 2.8).

CONCLUSIONS

Our findings support the role of As exposure via water from private wells in the incidence of GDM and that this association may be modified by body composition.

Pregnancy urinary phthalate metabolite concentrations and gestational diabetes risk factors

BACKGROUND

Epidemiologic studies suggest phthalate metabolite concentrations are associated with type 2 diabetes. GDM is a strong risk factor for type 2 diabetes. Little is known about phthalates and GDM risk factors (i.e. 1st trimester body mass index (BMI), gestational weight gain (GWG), and 2nd trimester glucose levels).

METHODS

A total of 350 women participating in Lifecodes pregnancy cohort (Boston, MA), delivered at term and had pregnancy urinary phthalate metabolite concentrations. Nine specific gravity-adjusted urinary phthalate metabolites were evaluated. General linear regression was used to assess associations between quartiles of phthalate metabolites and continuous 1st trimester BMI and late 2nd trimester blood glucose. Linear mixed models were used for total GWG. Multivariable logistic regression was used for phthalate concentrations and categorized GWG and impaired glucose tolerance defined as glucose≥140mg/dL based on a 50-gram glucose load test. Models were adjusted for potential confounders.

RESULTS

There were no associations between 1st trimester urinary phthalate metabolite concentrations and 1st trimester BMI. Mono-ethyl phthalate concentrations averaged across pregnancy were associated with a 2.17 increased odds of excessive GWG (95% CI: 0.98, 4.79). Second trimester mono-ethyl phthalate was associated with increased odds of impaired glucose tolerance (adj. OR: 7.18; 95% CI: 1.97, 26.15). A summary measure of di-2-ethylhexyl phthalate metabolite concentrations were inversely associated with impaired glucose tolerance (adj. OR: 0.25; adj. 95% CI: 0.08, 0.85).

CONCLUSIONS

Higher exposure to mono-ethyl phthalate, a metabolite of the parent compound of di-ethyl phthalate, may be associated with excessive GWG and impaired glucose tolerance; higher di-2-ethylhexyl phthalate was associated with reduced odds of impaired glucose tolerance.

Shift to Fatty Substrate Utilization in Response to Sodium-Glucose Cotransporter 2 Inhibition in Subjects Without Diabetes and Patients With Type 2 Diabetes

Pharmacologically induced glycosuria elicits adaptive responses in glucose homeostasis and hormone release. In type 2 diabetes (T2D), along with decrements in plasma glucose and insulin levels and increments in glucagon release, sodium-glucose cotransporter 2 (SGLT2) inhibitors induce stimulation of endogenous glucose production (EGP) and a suppression of tissue glucose disposal (TGD). We measured fasting and postmeal glucose fluxes in 25 subjects without diabetes using a double glucose tracer technique; in these subjects and in 66 previously reported patients with T2D, we also estimated lipolysis (from [(2)H5]glycerol turnover rate and circulating free fatty acids, glycerol, and triglycerides), lipid oxidation (LOx; by indirect calorimetry), and ketogenesis (from circulating β-hydroxybutyrate concentrations). In both groups, empagliflozin administration raised EGP, lowered TGD, and stimulated lipolysis, LOx, and ketogenesis. The pattern of glycosuria-induced changes was similar in subjects without diabetes and in those with T2D but quantitatively smaller in the former. With chronic (4 weeks) versus acute (first dose) drug administration, glucose flux responses were attenuated, whereas lipid responses were enhanced; in patients with T2D, fasting β-hydroxybutyrate levels rose from 246 ± 288 to 561 ± 596 µmol/L (P < 0.01). We conclude that by shunting substantial amounts of carbohydrate into urine, SGLT2-mediated glycosuria results in a progressive shift in fuel utilization toward fatty substrates. The associated hormonal milieu (lower insulin-to-glucagon ratio) favors glucose release and ketogenesis.

The utility of urinary myo-inositol as a marker of glucose intolerance

OBJECTIVE

The most common screening tests for glucose intolerance are fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c). Because it reflects the current status of hyperglycemia, urinary myo-inositol (UMI) may be useful. We evaluated UMI as a screening tool for glucose intolerance.

DESIGN AND METHODS

A cross-sectional, community-based population study of 1057 Japanese residents. 173 with an FPG level between 5.5 and 6.9 mmol/L and an HbA1c under 6.5% had an oral glucose tolerance test. We measured UMI level before (fasting UMI) and 2h after (2h-UMI) glucose ingestion. Δ-UMI was defined as the difference between fasting UMI and 2h-UMI.

RESULTS

Δ-UMI, 2h-UMI and HbA1c levels significantly increased as glucose intolerance worsened. Δ-UMI level was significantly positively correlated with 2h-UMI level (r=0.896, p<0.001). Using cutoff levels from receiver operating characteristic (ROC) analyses, the sensitivity of Δ-UMI (82.1%) and 2h-UMI (79.3%) were higher than that of HbA1c (48.3%). The area under the ROC curve values for Δ-UMI (0.903) and 2h-UMI (0.891) were higher than that for HbA1c (0.785).

CONCLUSIONS

2h-UMI is useful as a non-invasive screening of glucose intolerance.

Associations of serum and urinary magnesium with the pre-diabetes, diabetes and diabetic complications in the Chinese Northeast population

The effect of magnesium (Mg) deficiency on the prevalence of diabetes and diabetic complications has received a great attention. The present study investigated the association of Mg level in the serum or urine of the patients, lived in the Northeast areas of China, with either pre-diabetes or diabetes with and without complications. From January 2010 to October 2011, patients with type 1 diabetes (T1D, n = 25), type 2 diabetes (T2D, n = 137), impaired fasting glucose (IFG, n = 12) or impaired glucose tolerance (IGT, n = 15), and age/gender matched control (n = 50) were enrolled in the First Hospital of Jilin University. In T2D group, there were 24, 34, and 50 patients with nephropathy, retinopathy or peripheral neuropathy. Serum Mg levels in the patients with IGT, IFG, T2D, and T1D were significantly lower than that of control. The urinary Mg levels were significantly increased only in T2D and T1D patients compared to control. There was no difference for these two changes among T2D with and without complications; In addition, there was a significantly positive correlation of serum Mg levels with serum Ca levels only in T2D patients, and also a significantly positive correlation of urinary Mg levels with urinary Ca levels in control, IGT patients, and T2D patients. Simvastatin treatment in T2D patients selectively reduced serum Ca levels and urinary Mg levels. These results suggest that the potential impact of Mg deficiency on metabolic syndrome, diabetes and diabetic complications needs to be received special attention.

High urinary ACE2 concentrations are associated with severity of glucose intolerance and microalbuminuria

OBJECTIVE

Angiotensin-converting enzyme 2 (ACE2) plays an important role in glucose metabolism and renal function. However, the relationship between ACE2 and hyperglycemia or microalbuminuria has not been established in humans. We investigated whether urinary ACE2 levels are associated with abnormal glucose homeostasis and urinary albumin excretion.

METHODS

We developed an ELISA for quantifying ACE2 in urine. The ELISA was used to measure urinary ACE2 levels in 621 subjects with: normal glucose tolerance (NGT; n=77); impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) (n=132); and type 2 diabetes mellitus (T2DM, n=412). Insulin resistance was assessed by homeostasis model assessment for insulin resistance (HOMA-IR) index and urinary albumin excretion by urine albumin-to-creatinine ratio (ACR). Other biochemical and anthropometric parameters were measured.

RESULTS

Urinary ACE2 levels were significantly higher in insulin-resistant subjects with IFG, IGT, and T2DM than in the NGT group (P<0.001). Urinary ACE2 concentrations appeared to correlate with HOMA-IR, fasting blood glucose, triglyceride, high-sensitivity C-reactive protein, serum creatinine, urinary ACR, and systolic blood pressure (all P<0.05). After adjustment for impaired renal function and other metabolic parameters, urinary ACE2 concentration was still associated with a higher risk for T2DM (OR 1.80, 95% CI 1.05-3.08, P=0.02). In addition, urinary ACE2 levels were highly predictive of microalbuminuria after adjusting for clinical risk factors (OR 2.68, 95% CI 1.55-4.64, P<0.001).

CONCLUSION

Our data suggest that the urinary ACE2 level is closely associated with T2DM and is an independent risk factor for microalbuminuria.

Longer HSD11B2 CA-repeat in impaired glucose tolerance and type 2 diabetes

Type 2 11β-hydroxysteroid dehydrogenase encoded by the HSD11B2 gene converts cortisol to inactive cortisone, and alteration in this enzymatic activity might affect glucose homeostasis by affecting circulating levels or tissue availability of glucocorticoids. We investigated the association of HSD11B2 variant with glucose homeostasis. Subjects with normal glucose tolerance (n=585), impaired glucose tolerance (n=202) and type 2 diabetes (n=355) were genotyped for a highly polymorphic CA-repeat polymorphism in the first intron of HSD11B2. Allele and genotype frequencies differed between normal and impaired glucose tolerance (P = 0.0014 and 0.0407, respectively; 4 degree of freedom) or type 2 diabetes (P = 0.0053 and 0.0078), with significant linear trends between the repeat length and the phenotype fraction. In normal subjects, total CA-repeat length was negatively correlated with fasting insulin and HOMA-β. Thus, subjects having more CA repeats are susceptible to developing abnormal glucose tolerance, whereas normal subjects carrying more CA repeats appeared to have frugal characteristics in insulin secretion.

Cumulative glycemia and microangiopathy in subjects with impaired glucose regulation in the Inter99 study

AIMS

To assess cumulative glycemia, microvascular characteristics, and associated risk factors for diabetes in subjects with impaired glucose regulation.

METHODS

Cross-sectional, population-based study comprising systemic characteristics in 6487 participants and ocular characteristics in 970 participants.

RESULTS

Lens fluorescence, a quantitative index of life-long cumulative glycemia, was increased by 7.5% (CI(95) 0.37-15.1%) in subjects with impaired fasting glucose, by 13.0% (CI(95) 5.5-21%) in subjects with combined impaired fasting glucose and impaired glucose tolerance (IFG+IGT), and by 11.8% (CI(95) 6.8-17.1%) in subjects with screen-detected diabetes compared to normoglycemic subjects, adjusted for age, sex, and smoking. The prevalences of microalbuminuria and retinopathy were significantly increased in subjects with screen-detected diabetes after adjusting for age, sex and systolic blood pressure. The prevalences of associated risk factors for diabetes were elevated in all categories of abnormal glucose regulation compared to normoglycemic subjects.

CONCLUSIONS

Life-long cumulative glycemia, microangiopathy, and associated risk factors for diabetes were significantly elevated in subjects with abnormal glucose metabolism, most prominently in subjects with IFG+IGT and in subjects with screen-detected diabetes. These results provide the first objective evidence that cumulative glycemic load is increased at the earliest stage of impaired glucose regulation.

Effects of pyridoxamine (K-163) on glucose intolerance and obesity in high-fat diet C57BL/6J mice

Advanced glycation end products (AGEs) contribute to the pathogenesis of diabetes-associated complications. Previously, we reported the possible effect of pyridoxamine (K-163), an AGE inhibitor, on improvement of glucose intolerance in type 2 diabetes mellitus KK-A(y)/Ta mice. Recently, AGEs and oxidative stress have been shown to induce insulin resistance. The objective of the present study is to examine the effect of pyridoxamine on glucose intolerance and oxidative stress. C57BL/6J mice were divided into 3 groups as follows: low-fat diet, high-fat diet, and high-fat diet with pyridoxamine treatment. Body and adipose tissue weight, serum insulin, hydrogen peroxide, malondialdehyde and AGE, and urinary 8-hydroxy-2'-deoxyguanosine levels were measured. Nicotinamide adenine dinucleotide phosphate subunits, antioxidant enzymes, and adipocytokine messenger RNA expressions in the adipose tissues were evaluated. Akt/protein kinase B activity and glucose transporter 4 translocation in skeletal muscle were also evaluated. Body and adipose tissue weights of the pyridoxamine treatment group were significantly decreased compared with those of the high-fat diet group. Pyridoxamine attenuated serum hydrogen peroxide, malondialdehyde and AGE, and urinary 8-hydroxy-2'-deoxyguanosine and nicotinamide adenine dinucleotide phosphate oxidase expression; increased antioxidant enzyme expression; and improved dysregulation of adipocytokines in adipose tissues. Pyridoxamine improved blood glucose levels after glucose injection and fasting hyperinsulinemia. Suppressed Akt/protein kinase B activity and glucose transporter 4 translocation in skeletal muscle in high-fat diet mice were improved by pyridoxamine treatment. It appears that the antioxidative effect of pyridoxamine is associated with improvement of glucose intolerance and obesity in C57BL/6J mice fed a high-fat diet. We assume that pyridoxamine may be useful in the treatment of the obesity-associated metabolic syndrome.

High sensitive C-reactive protein, adiponectin, and urine albumin excretion rate in Chinese coronary artery disease patients with different glucose tolerance status

BACKGROUND

Serum high sensitive C-reactive protein (hs-CRP), adiponectin levels and urine albumin excretion rate (UAER) are probably associated with inflammation and atherosclerosis. The aim of this study was to determine the three markers in coronary artery disease (CAD) subjects with different glucose tolerance status in a Chinese population and further explore the levels of the three markers in these subjects and the possible association of these markers with CAD risk factors and the severity of CAD as well.

METHODS

A total of 242 subjects with angiographically documented CAD were recruited, and then assigned to three groups: the normal glucose tolerance (NGT) + CAD group, including 100 CAD patients with NGT; the impaired glucose tolerance (IGT) + CAD group, 40 CAD patients with IGT; the type 2 diabetes mellitus (T2DM) + CAD group, 102 CAD patients with T2DM. Serum hs-CRP, adiponectin levels as well as UAER were measured in all subjects.

RESULTS

Serum hs-CRP levels were increased in the T2DM + CAD group compared with the NGT + CAD group (4.71 +/- 2.59) vs (3.60 +/- 2.46) mg/L, P = 0.037. Serum adiponectin levels were gradually decreased from the NGT + CAD to IGT + CAD to T2DM + CAD groups, (5.99 +/- 1.84), (5.82 +/- 1.72) and (4.65 +/- 1.71) mg/L, P = 0.002 and 0.040 for NGT + CAD and IGT + CAD groups vs T2DM + CAD group, respectively. While the UAER was gradually increased from the NGT + CAD to IGT + CAD to T2DM + CAD groups, (6.42 +/- 2.51), (6.89 +/- 2.94) and (15.03 +/- 4.22) microg/min (P < 0.001) for NGT + CAD and IGT + CAD groups vs T2DM + CAD group. Multiple linear stepwise regression analysis showed that waist-hip ratio (WHR) and low density lipoprotein cholesterol (LDL-C) were the significant determinants of serum hs-CRP levels; triglyceride (TG), high density lipoprotein cholesterol (HDL-C), age, WHR, T2DM, 2-hour serum insulin (2hINS), sex, and apolipoprotein B were the significant determinants of serum adiponectin levels; and systolic blood pressure (SBP), T2DM, and hemoglobin A1c (HbA1c) were the significant determinants of UAER in all subjects (R(2) = 0.070, 0.352, and 0.214, respectively). However, no significant correlation was seen for hs-CRP, adiponectin and UAER with the severity of CAD. Hs-CRP levels were significantly correlated with UAER.

CONCLUSIONS

There was a trend of increased serum hs-CRP levels from the NGT + CAD to IGT + CAD to T2DM + CAD groups, though it only showed significance in the T2DM + CAD group compared with the NGT + CAD group. Serum adiponectin levels were decreased and UAER was increased from the NGT + CAD to IGT + CAD to T2DM + CAD groups. Increased UAER and serum hs-CRP, and decreased adiponectin levels were associated with traditional CAD risk factors but failed to be correlated with the severity of CAD. Hs-CRP levels were significantly correlated with UAER.

Prevalence and risk factors for urinary incontinence in women with type 2 diabetes and impaired fasting glucose: findings from the National Health and Nutrition Examination Survey (NHANES) 2001-2002

OBJECTIVE

Diabetes is associated with increased risk of urinary incontinence. It is unknown whether women with pre-diabetes, or impaired fasting glucose (IFG), have increased prevalence of incontinence. We determined the prevalence of, and risk factors for, incontinence among U.S. women with diabetes and IFG.

RESEARCH DESIGN AND METHODS

The 2001-2002 National Health and Nutrition Examination Survey measured fasting plasma glucose and obtained information about diabetes and urinary incontinence among 1,461 nonpregnant adult women. Self-reported weekly or more frequent incontinence, both overall and by type (urge and stress), was our outcome.

RESULTS

Of the 1,461 women, 17% had diabetes and 11% met criteria for IFG. Prevalence of weekly incontinence was similar among women in these two groups (35.4 and 33.4%, respectively) and significantly higher than among women with normal fasting glucose (16.8%); both urge and stress incontinence were increased. In addition to well-recognized risk factors including age, weight, and oral estrogen use, two microvascular complications caused by diabetes, specifically macroalbuminuria and peripheral neuropathic pain, were associated with incontinence.

CONCLUSIONS

Physicians should be alert for incontinence, an often unrecognized and therefore undertreated disorder, among women with diabetes and IFG, in particular those with microvascular complications. The additional prospect of improvements in their incontinence may help motivate some high-risk women to undertake difficult lifestyle changes to reduce their more serious risk of diabetes and its sequelae.

A comparison of urinary albumin excretion rate and microalbuminuria in various glucose tolerance subjects

AIMS

To investigate the difference of urinary albumin excretion rate (UAER) and microalbuminuria (MAU) in various glucose tolerance subjects, especially between isolated-impaired glucose tolerance subjects and isolated-impaired fasting glycaemia subjects.

METHODS

A total of 2934 subjects were divided into five groups with various glucose tolerances, based on a 75-g oral glucose tolerance test. Microalbuminuria was defined when urinary albumin excretion rate was between 20 and 200 microg/min.

RESULTS

(i) The UAER in the newly diagnosed Type 2 diabetes mellitus group, impaired glucose tolerance/impaired fasting glycaemia group and isolated-impaired glucose tolerance group were all higher than that in the isolated-impaired fasting glycaemia group and normal glucose tolerance group, but it was comparable between isolated-impaired fasting glycemia group and normal glucose tolerance group. The prevalence of MAU and the odds ratio for MAU with adjustment for age and sex in various glucose tolerance groups showed the same trend as the UAER. (ii) After adjusting for age and sex, there is a significant association between logUAER and independent risk factors (partial correlation coefficients: r = 0.26 for 2-h post-challenge blood glucose, r = 0.26 for systolic blood pressure, r = 0.27 for diastolic blood pressure, r = 0.27 for body mass index and r = -0.13 for high density lipoprotein-cholesterol, all P < 0.001). The risks for MAU were 2-h post-challenge blood glucose, body mass index and diastolic blood pressure, while high density lipoprotein-cholesterol was protective.

CONCLUSIONS

The urinary albumin excretion rate and prevalence of microalbuminuria were higher in isolated-impaired glucose tolerance subjects than those in isolated-impaired fasting glycaemia subjects. At early abnormal glucose tolerance stage, the increasing post-challenge glycaemia might be a more important risk factor for urinary albumin excretion rate and microalbuminuria than increasing fasting glycaemia.

A study of urinary myo-inositol as a sensitive marker of glucose intolerance

BACKGROUND

We assessed the possibility of using myo-inositol as a marker of glucose intolerance.

METHODS

We measured urinary myo-inositol enzymatically before and 2 h after a 75-g oral glucose tolerance test in 564 volunteers, who were divided into four groups [normal glucose tolerance (NGT), impaired fasting glucose (IFG), impaired glucose tolerance (IGT), and diabetes mellitus (DM)]. Furthermore, we classified NGT into NGT-A (2-h blood glucose <120 mg/dl and 2-h glucosuria <50 mg/dl) and NGT-B (remaining NGT subjects). We then compared deltamyo-inositol (myo-inositol/creatinine ratio: 2-h after glucose load--before load) of each group to investigate the relationship between glucose intolerance and deltamyo-inositol.

RESULTS

The glucose tolerance of NGT-B appeared to have deteriorated compared with NGT-A as determined by blood glucose, insulin, and glucosuria. There was very little effect of gender or age on deltamyo-inositol in NGT-A. deltamyo-inositol was significantly higher than that in NGT-A (0.5+/-7.1 mg/g Cr) not only in IFG (8.7+/-19.5 mg/g Cr, P<0.0001), IGT (14.8+/-22.9 mg/g Cr, P<0.0001) and DM (79.5+/-37.1 mg/g Cr, P<0.0001), but in NGT-B (7.4+/-12.7 mg/g Cr, P<0.0001). With 2 mg/g Cr as a tentative cut-off for deltamyo-inositol to detect NGT-A, sensitivity and specificity were 68% and 72%, respectively.

CONCLUSIONS

The deltamyo-inositol can be use of a non-invasive and sensitive marker for glucose intolerance.

Glucose metabolism in relatives of type 1 diabetic patients with albuminuria

OBJECTIVE

Diabetic nephropathy in type 1 diabetes is associated with familial aggregation of diabetes. In order to explore the mechanisms behind this association, we assessed glucose metabolism in glucose-intolerant relatives of type 1 diabetic patients with (ALB+) or without (ALB-) elevated urinary albumin excretion rate (UAER).

METHODS

Glucose tolerance and insulin secretion were assessed using an oral glucose tolerance test (OGTT) and insulin sensitivity was measured with the short insulin tolerance test (ITT).

RESULTS

One hundred and fourteen parents and siblings of 43 type 1 diabetic patients with ALB+ (UAER > or = 20 microg/min) were identified and 93 parents and siblings of 39 patients with ALB- (UAER < 20 microg/min). From this pool, a further selection was made of those (25 and 13 relatives of patients with ALB+ and ALB-, respectively) with mild abnormalities of glucose metabolism (fasting plasma glucose < 7.8 mmol/L; 2 h plasma glucose > or = 7.8 mmol/L in the OGTT). No difference in insulin sensitivity was discernible between the two groups of relatives (KITT 3.3 +/- 1.0 vs. 3.2 +/- 1.0%/min, p=NS). Although there were no significant differences in the incremental areas under glucose or insulin curves (AUC) between relatives of ALB+ and ALB- in the OGTT, the insulin secretory response to the rise in plasma glucose was impaired in relatives of patients with ALB+ (insulin AUC/glucose AUC: 7.1 [1.1-30.8] vs. 9.8 [3.6-52.2], p=0.039).

CONCLUSIONS

Glucose-intolerant relatives of patients with elevated UAER seem to be characterized by impaired insulin secretion. Genetic or environmental factors related to impaired insulin secretion may be important in the development of diabetic nephropathy.

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.

Abnormality in urinary protein excretion in Japanese men with impaired glucose tolerance

OBJECTIVE

To examine whether subjects with impaired glucose tolerance (IGT) for more than 2 years have any abnormality in the kidney.

RESEARCH DESIGN AND METHODS

We measured urinary excretion rate and clearance of various plasma proteins with different molecular radii and different isoelectric points in 22 Japanese men with IGT (IGT group) and 37 age-matched healthy control subjects (control group).

RESULTS

Clearance of ceruloplasmin (molecular radius approximately 45 A; isoelectric point 4.4), IgG4 (molecular radius 55 A; isoelectric point 5.4), and IgG (molecular radius 55 A; isoelectric point 7.4) was significantly higher in the IGT group than in the control group, whereas there were no significant differences in urinary excretion rate of albumin (molecular radius 36 A; isoelectric points 4.8-5.2) and clearance of alpha 2-macroglobulin (molecular radius 88 A; isoelectric point 5.4) between the two groups.

CONCLUSIONS

In the present study, we found that clearance of neutral-charged IgG, negatively charged IgG4, and ceruloplasmin with molecular radii of approximately 45-55 A was selectively increased in IGT subjects. This finding does not seem to be explained by impairment of charge and pore-size selectivity in the glomerulus. Therefore, considering the present result together with our recent finding that enhanced glomerular filtration rate (GFR) after acute protein loading in healthy subjects induced a selective increase in clearance of IgG, IgG4, and ceruloplasmin, we suggest that increased intraglomerular hydraulic pressure, although enhanced GFR was not demonstrated, may be at work in these mildly hyperglycemic subjects.

Urinary excretion of ceruloplasmin is elevated in the subjects with "borderline glucose tolerance test"

To examine whether or not there are any renal alterations in subjects with borderline glucose tolerance and in patients with non-insulin dependent diabetes mellitus (NIDDM) classified by the criteria of Japan Diabetic Association, urinary excretions of plasma proteins including albumin, ceruloplasmin (Cerulo) and IgG were measured in timed overnight urine samples. Eighty middle-aged, non-obese, normotensive, untreated men with urinary albumin excretion rates below 20 microg/minutes, beta2-microglobulin excretion rates below 140 microg/minutes and creatinine clearance values exceeding 80 ml x min(-1) x (1.73 m2)(-1) were included in this study. Three groups were defined according to the results of 75 g oral glucose tolerance test (OGTT) as follows: D group, 10 subjects with NIDDM; B group, 40 subjects with "borderline glucose tolerance test" and N group, 30 subjects with normal glucose tolerance. The fractional clearance (theta) of Cerulo, but not albumin and IgG, was elevated in 37. 5% of the B group compared with the upper limit of that of the N group. Furthermore, theta-Cerulo and theta-IgG increased in the D group compared with those of the N and the B groups. Recently, we found that theta-Cerulo and theta-IgG increased in healthy volunteers when GFR was elevated by acute protein loading and that increase in theta-Cerulo is remarkable than increase in theta-IgG. The present result, taken together with our recent finding mentioned above, suggests that increases in theta-Cerulo and theta-IgG may not be due to an impairment of charge selectivity in the glomerular basement membrane, but due to an increase of intraglomerular hydraulic pressure.

Relationship between serum 1,5-anhydroglucitol and urinary excretion of N-acetylglucosaminidase and albumin determined at onset of NIDDM with 3-year follow-up

OBJECTIVE

This prospective study was designed to elucidate the relationship between the serum level of 1,5-anhydroglucitol (1,5AG) and the urinary excretion of N-acetylglucosaminidase (NAG) and albumin in patients who were in the early stages of diabetes.

RESEARCH DESIGN AND METHODS

A total of 1,062 male nondiabetic subjects with impaired glucose tolerance were monitored for blood glucose level once every 2-3 months, and the values were evaluated. Of these 1,062 subjects, 112 showed a worsening of glycemia during the observation period to the level seen in diabetes. We began to monitor the glycemia and parameters of renal damage in the 112 patients from the onset of diabetes.

RESULTS

The urinary excretion of NAG and albumin were elevated even at the onset of diabetes. The abnormal excretion of NAG and albumin was associated with a change in serum 1,5AG and was quickly reversible when the serum 1,5AG improved. In the 3 years after the onset of diabetes, we obtained at least 18 measurements of one parameter for each patient and calculated the mean. Urinary NAG was found to be significantly correlated with the fasting plasma level of glucose (FPG; r = 0.512, P < 0.0001), the level of HbA1 (r = 0.351, P = 0.001), and the level of 1,5AG (r = -0.790, P < 0.0001). The urinary excretion of albumin was weakly but significantly correlated with levels of FPG (r = 0.383, P < 0.0001) and HbA1 (r = 0.337, P < 0.0001), but it was more strongly correlated with 1,5AG (r = -0.632, P < 0.0001). The level of 1,5AG was significantly correlated with FPG (r = -0.681, P < 0.0001) and HbA1 (r = -0.609, P < 0.0001).

CONCLUSIONS

When the renal damage is not severe, the serum level of 1,5AG appeared to be an indicator of the reversible renal damage caused by hyperglycemia, as well as of the severity of the glycemia itself.

Analysis of urinary albumin, transferrin, N-acetyl-beta-D-glucosaminidase and beta2-microglobulin in patients with impaired glucose tolerance

We investigated the changes in urinary albumin and urinary transferrin as glomerular proteins, and in urinary N-acetyl-beta-D-glucosaminidase and urinary beta2-microglobulin as tubular proteins, in patients with impaired glucose tolerance. We attempted to compare the proteins of normal subjects to those of diabetics with pre-nephropathy. Transferrin and N-acetyl-beta-D-glucosaminidase levels were significantly increased in patients with impaired glucose tolerance, while albumin and beta2-microglobulin levels were only slightly increased. In addition, there was no significant difference in transferrin levels between patients with impaired glucose tolerance and type 2 diabetics with pre-nephropathy. In our observation, although albumin levels were only slightly increased in patients with impaired glucose tolerance, a sharp increase in transferrin levels was reflected in patients with glomerular disorders. In addition, since N-acetyl-beta-D-glucosaminidase levels varied markedly, tubular disorders were suspected. It should be stressed that increased parameters for both glomerular and tubular disorders in group C--patients who showed abnormal levels in three proteins--had already been observed in some patients with impaired glucose tolerance. Therefore, the evaluation of the mutual relationships between various urinary protein components in patients with impaired glucose tolerance will become a more important assessment tool than that of single urinary protein components.