Influence of an SGLT2 inhibitor, tofogliflozin, on the resting heart rate in relation to adipose tissue insulin resistance

AIMS

To examine the effects of a sodium-glucose co-transporter 2 (SGLT2) inhibitor, tofogliflozin, on resting heart rate by exploring baseline factors that independently influenced changes in the resting heart rate.

METHODS

Data on 419 participants in tofogliflozin phase 2/3 trials were analysed. Changes in resting heart rate from baseline to week 24 were analysed using an analysis of covariance (ANCOVA) model with groups (tofogliflozin/placebo) as a fixed effect and baseline values as covariates. The antilipolytic effect was evaluated as adipose tissue insulin resistance (Adipo-IR) and was calculated as the product of fasting insulin and free fatty acid. Multivariate analysis evaluated independent factors for changes in resting heart rate from baseline to week 24.

RESULTS

Of the participants, 58% were men, and mean age, HbA_1c , BMI and resting heart rate were 57.6 years, 65 mmol/mol (8.1%), 25.5 kg/m² and 66 bpm, respectively. At week 24, adjusted mean difference vs. placebo in the change from baseline was -2.3 bpm [95% confidence interval (CI) -4.6, -0.1] with tofogliflozin. Changes in resting heart rate were positively correlated with changes in Adipo-IR, whereas reductions in HbA_1c , body weight and blood pressure were similar independent of changes in resting heart among quartiles of resting heart rate change. On multivariate analysis, higher baseline resting heart rates and Adipo-IR values were significantly associated with greater reductions in resting heart rate.

CONCLUSIONS

Tofogliflozin corrected resting heart rate levels in accordance with baseline levels. Correction of high resting heart rates may be attributed to improved adipose tissue insulin resistance, leading to correction of hyperinsulinaemia.

P17 In-hospital mortality and clinical features of Japanese patients with acute myocardial infarction diagnosed by universal definition in real world from kanagawa-acute cardiovascular registry (K-ACTIVE)

Background

Cardiac troponin (cTn) has been used as the preferred biomarker of myocardial injury for diagnosis of acute myocardial infraction (AMI) by universal definition. A large number of patients formerly classified by creatine kinase (CK) as unstable angina with the WHO criteria in Japan are now diagnosed by cTn as non-ST elevation myocardial infarction (NSTEMI). In this report, we aimed to understand its prevalence and clinical features of AMI diagnosed by using universal definition and the WHO criterial in real world. 

Method

This registry is a cross-sectional study of 53 facilities in Kanagawa prefecture of Japan. 4372 AMI patients were enrolled who received primary percutaneous coronary intervention (PCI) between October 1, 2015 and January 29, 2019. Patients were divided into 3 groups, 3268 patients with ST elevation myocardial infarction (STEMI), 628 patients with NSTEMI patients who satisfied the WHO criteria with CK elevation beyond twice upper limit of normal (NSTEMI + CK), and 476 patients with NSTEMI who didn’t satisfy the WHO criteria without CK elevation (NSTEMI-CK).

Result

Baseline clinical characteristics of the study patients are shown in Table 1. In-hospital mortality was significantly lower in patients with NSTEMI-CK (1.9%) than in STEMI (6.0%, P < 0.001) and NSTEMI + CK (5.3%, P < 0.004) (Figure 1). Kaplan-Meier analyses for 0-30 days of cardiac death are shown in Figure 2. From day 0, the Kaplan-Meier curves began to diverge in favor of NSTEMI-CK for up to 30 days.

Conclusion

AMI patients showed distinct clinical features depends on the type. We should be aware of the difference for the diagnosis of AMI by using universal definitions.

Table 1. 　 STEMI (n = 3268) NSTEMI + CK (n = 628) NSTEMI-CK (n = 476) STEMI vs NSTEMI + CK P value STEMI vs NSTEMI-CK P value NSTEMI + CK vs NSTEMI-CK P value Age(years) 68(59-77) 69(61-78) 70(61-79) 　 　 　 Male 76% 77% 75% 0.54 0.74 0.47 Concomitant diseases 　 　 　 　 　 　 Hypertention 65.4% 70.5% 69.3% 0.013 0.097 0.65 Diabetes 33.5% 36.5% 37.3% 0.15 0.11 0.78 Dyslipidemia 56.1% 61.2% 61.3% 0.018 0.03 0.96 Hemodialysis 2.3% 2.1% 6.8% 0.86 <0.001 0.01 Smoking 66.3% 63.1% 64.6% 0.13 0.48 0.62 Atrial fibrillation 9.6% 10.7% 14.4% 0.57 0.04 0.23 Previous MI 8.3% 17.3% 15.7% <0.001 <0.001 0.47 In-hospital mortality 6.0% 5.3% 1.9% 0.49 <0.001 0.004

Abstract P17 Figure 1. 2.

Network meta-analysis of the relative efficacy of bariatric surgeries for diabetes remission

BACKGROUND

Bariatric surgery leads to a higher remission rate for type 2 diabetes mellitus than non-surgical treatment. However, it remains unsolved which surgical procedure is the most efficacious. This network meta-analysis aimed to rank surgical procedures in terms of diabetes remission.

METHODS AND FINDINGS

We electronically searched for randomized controlled trials in which at least one surgical treatment was included among multiple arms and the diabetes remission rate was included in study outcomes. A random-effects network meta-analysis was performed within a frequentist framework. The hierarchy of treatments was expressed as the surface under the cumulative ranking curve value. Results of the analysis of 25 eligible randomized controlled trials that covered non-surgical treatments and eight surgical procedures (biliopancreatic diversion [BPD], BPD with duodenal switch, Roux-en Y gastric bypass, mini gastric bypass [mini-GBP], laparoscopic adjustable gastric banding, laparoscopic sleeve gastrectomy, greater curvature plication and duodenal-jejunal bypass) showed that BPD and mini-GBP had the highest surface under the cumulative ranking curve values among the eight surgical treatments.

CONCLUSION

Current network meta-analysis indicated that BPD or mini-GBP achieved higher diabetes remission rates than the other procedures. However, the result needs to be interpreted with caution considering that these procedures were in the minority of bariatric surgeries.

Role of fatty liver in the association between obesity and reduced hepatic insulin clearance

AIM

Hepatic insulin clearance (HIC) is important in regulating plasma insulin levels. Diminished HIC causes inappropriate hyperinsulinaemia, and both obesity and fatty liver (FL), which are known to decrease HIC, can be found either together in the same patient or on their own. The mechanism by which obesity reduces HIC is presumed to be mediated by FL. However, few reports have examined the role of FL in the relationship between obesity and HIC in type 2 diabetes (T2D) patients. Therefore, our study investigated the association of HIC with clinical factors, including insulin sensitivity indices, focusing on the presence or absence of FL and obesity in T2D patients.

METHOD

Baseline data from 419 patients with T2D (279 men, 140 women; mean age: 57.6 years; body mass index: 25.5kg/m²) controlled by diet and exercise were analyzed. HIC was calculated from the ratio of fasting c-peptide to fasting insulin levels (HIC_CIR). Correlation analyses between HIC_CIR and clinical variables were performed using Pearson's product-moment correlation coefficients and single regression analysis in all participants and in those with obesity and FL either alone or in combination.

RESULTS

HIC_CIR was significantly correlated with whole-body insulin sensitivity indices and influenced by FL, but only in the FL group was obesity independently influenced HIC level. HIC_CIR decreased in those with both FL and obesity compared with those with only one such complication.

CONCLUSION

HIC_CIR may be used to evaluate whole-body insulin sensitivity in T2D. Also, compared with obesity, the influence of FL strongly contributed to a reduced HIC.

TRIAL REGISTRATION NUMBER

These trials were registered by the Japan Pharmaceutical Information Centre clinical trials information (JapicCTI) as 101349 and 101351.

Impact of body mass index and metabolic phenotypes on coronary artery disease according to glucose tolerance status

OBJECTIVE

This study aimed to examine the impact of obesity, as defined by body mass index (BMI), and a metabolically unhealthy phenotype on the development of coronary artery disease (CAD) according to glucose tolerance status.

METHODS

. Metabolically unhealthy individuals were defined as those with one or more of the following conditions: hypertension, hypertriglyceridaemia and/or low HDL cholesterol. A Cox proportional hazards regression model identified variables related to CAD incidence.

RESULTS

The prevalences of obese subjects with normal glucose tolerance, prediabetes and diabetes were 21%, 34% and 53%, whereas those for metabolically unhealthy people were 43%, 60% and 79%, respectively. Multivariate analysis showed that a metabolically unhealthy phenotype increases hazard ratios (HRs) for CAD compared with a metabolically healthy phenotype, regardless of glucose tolerance status (normal glucose tolerance: 1.98, 95% CI: 1.32-2.95; prediabetes: 2.91, 95% CI: 1.85-4.55; diabetes: 1.90, 95% CI: 1.18-3.06). HRs for CAD among metabolically unhealthy non-obese diabetes patients and obese diabetes patients with a metabolically unhealthy status were 6.14 (95% CI: 3.94-9.56) and 7.86 (95% CI: 5.21-11.9), respectively, compared with non-obese subjects with normal glucose tolerance and without a metabolically unhealthy status.

CONCLUSION

A metabolically unhealthy state can associate with CAD independently of obesity across all glucose tolerance stages. Clinicians may need to consider those with at least one or more conditions indicating a metabolically unhealthy state as being at high risk for CAD regardless of glucose tolerance status.

Severe hypoglycaemia is a major predictor of incident diabetic retinopathy in Japanese patients with type 2 diabetes

AIM

Hypoglycaemia is a common complication in diabetes patients. However, its relationship with retinopathy has not been well documented in patients with type 2 diabetes (T2D). This study aimed to investigate the associations between hypoglycaemia and the incidence and progression of diabetic retinopathy (DR).

METHODS

In this longitudinal cohort study, which was part of the Japan Diabetes Complications Study (JDCS), adult patients with T2D were recruited at 59 diabetes clinics across Japan. Their history of hypoglycaemia was assessed by standardized self-reported questionnaires. Severe hypoglycaemia was defined as having at least one episode with coma requiring an outpatients visit or hospitalization. Adjusted hazard ratios (HRs) for incidence and progression of DR over 8 years of follow-up were determined.

RESULTS

Of 1221 patients without DR, 127 (10.4%) had experienced non-severe hypoglycaemia within the previous year, whereas 10 (0.8%) reported severe hypoglycaemia episodes. During the 8-year follow-up involving 8492 person-years, 329 patients developed DR. In 410 patients with prevalent DR, the adjusted HRs for incident DR were 4.35 (95% CI: 1.98-9.56; P<0.01) and, for progression of DR, 2.29 (95% CI: 0.45-11.78; P=0.32) with severe hypoglycaemia.

CONCLUSION

Having a history of severe hypoglycaemia was one of the strongest predictors of incident DR in patients with T2D, with a fourfold increased risk. Identifying patients with greater risks of DR based on their history of hypoglycaemia may help to personalize risk evaluation in patients with diabetes.

Prevalence of resistant hypertension and associated factors in Japanese subjects with type 2 diabetes

OBJECTIVE

The prevalence of treatment resistant hypertension (RH) depends on methods used for blood pressure (BP) measurements, goals of BP, and therapeutic efforts in terms of medication and adherence. We focused on diabetic subjects and explored the prevalence of RH in primary care practice.

METHODS

In 1737 subjects with type 2 diabetes who continued regular visits, office BP was evaluated by multiple measurements over one year. RH was defined as using more than four antihypertensive drugs or failure to achieve the goal with three antihypertensive drugs from different classes. The RH prevalence was investigated with BP goals <130/80 and 140/90 mmHg.

RESULTS

The percentage of subjects who achieved BP goals <130/80 and 140/90 were 70.5% and 93.8% with adherence to medication ≥95%, and the corresponding prevalence rates of RH in treated subjects were 28.4% and 21.8%, respectively. Factors independently associated with RH were age (odds ratio 1.02 [95% CI 1.01-1.04]), body mass index (1.10 [1.06-1.13]), variability in systolic BP (1.06 [1.02-1.09]), triglycerides (2.86 [1.34-6.11]), macroalbuminuria (3.33 [2.03-5.48]), estimated glomerular filtration rate (0.98 [0.97-0.99]), retinopathy (1.91 [1.39-2.61]), and family history of hypertension (1.85 [1.23-2.21]). Worsening albuminuria and glomerular filtration rate enhanced the prevalence of RH in a graded manner.

CONCLUSION

Careful estimation of office BP values over one year with a high achievement of BP goals and adequate adherence revealed that the prevalence of RH in type 2 diabetes is high. RH was characterized by accumulation of cardiovascular genetic and environmental risks.

Fatal tracheal aspergillosis during rituximab combined chemotherapy for diffuse large B-cell lymphoma that developed after lung transplantation

Invasive tracheal aspergillosis (ITA) is an infection that is unique to patients who have undergone lung transplantation (LT). Although the activity of this disease often appears on imaging, we encountered a case of ITA that became exacerbated, despite few computed tomography (CT) findings, during rituximab combined chemotherapy for diffuse large B-cell lymphoma. ITA developed during immunosuppressive therapy after LT. Because CT findings may show false-negative results, bronchoscopy is recommended for such cases.

Pioglitazone treatment and cardiovascular event and death in subjects with type 2 diabetes without established cardiovascular disease (JDDM 36)

AIMS

The protective association of pioglitazone with cardiovascular events and death was investigated over 6-years in large-scale type 2 diabetic subjects without established cardiovascular disease in a primary care setting.

METHODS

A six-year observational cohort study including 2864 subjects with type 2 diabetes without established cardiovascular disease was performed. The primary endpoint was a composite of first occurrence of cardiovascular disease or death. The effect of pioglitazone use at a baseline year with a Cox proportional hazard model and the time-dependent use in each one-year examination interval with a pooled logistic regression model were analyzed.

RESULTS

Baseline use of pioglitazone (n=493) did not show a statistically protective effect on the primary endpoint (n=175), although it tended to reduce the risk (adjusted hazard ratio 0.67 [95% CI: 0.43-1.05]). However, pooled logistic regression analysis indicated a significant protective association of pioglitazone with the primary endpoint (0.58 [0.38 to 0.87] and cardiovascular disease (0.54 [0.33-0.88]), independent of concurrent levels of blood glucose, blood pressure, lipids, albuminuria, and renal function. In particular, this protective association was observed in those with diabetic nephropathy regardless of the daily dose of pioglitazone. Among a total of 898 subjects who took pioglitazone during the period, 43% experienced a discontinuation at least once; however, serious adverse effects were rare.

CONCLUSIONS

This observational study indicated a protective association of pioglitazone with cardiovascular disease and death in type 2 diabetic subjects without established vascular disease, particularly those with nephropathy.

Risk of the development of Type 2 diabetes in relation to overall obesity, abdominal obesity and the clustering of metabolic abnormalities in Japanese individuals: does metabolically healthy overweight really exist? The Niigata Wellness Study

AIMS

We investigated the risk of developing diabetes across various metabolic phenotypes by considering the presence of overall adiposity or abdominal adiposity and the number of metabolic abnormalities and aimed to clarify whether a 'healthy overweight' phenotype, that is, overweight with no metabolic abnormalities, was protective of the development of diabetes.

METHODS

We studied 29 564 Japanese individuals without diabetes. The 5-year incidence of diabetes was assessed according to a combination of either overweight (BMI ≥ 25.0 kg/m(2) ) or abdominal obesity (waist circumference ≥ 90 cm in men and ≥ 80 cm in women) and the number of metabolic factors present (hypertension, elevated triglyceride concentration, low HDL cholesterol concentration and impaired fasting glucose).

RESULTS

A total of 1188 individuals developed diabetes. Compared with normal weight individuals with none of the four metabolic abnormalities, in overweight individuals with none of the four abnormalities there was an odds ratio (OR) of 2.32 [95% confidence interval (CI) 1.50, 3.59] for diabetes; having any one metabolic abnormality increased the risk of developing diabetes among normal weight individuals [OR 3.23 (2.55, 4.10)] and overweight individuals [OR 5.00 (3.77, 6.63)]. Among overweight individuals, the presence of impaired fasting glucose alone substantially elevated the risk of diabetes by 8.98-fold (5.52, 14.6) in comparison with the absence of the four metabolic factors.

CONCLUSIONS

Being 'healthy overweight' was associated with a higher OR of developing future diabetes among Japanese individuals than normal weight individuals with no metabolic abnormalities, and being overweight with one or more abnormalities had a further elevated OR compared with 'healthy overweight' people.

Comparison of different aspects of BMI history to identify undiagnosed diabetes in Japanese men and women: Toranomon Hospital Health Management Center Study 12 (TOPICS 12)

AIMS

To examine current BMI and various aspects of BMI history as pre-screening tools for undiagnosed diabetes in Japanese individuals.

METHODS

This cross-sectional study included 16 226 men and 7026 women aged 30-75 years without a self-reported history of clinician-diagnosed diabetes. We estimated the probability of having undiagnosed diabetes (fasting glucose ≥ 7.0 mmol/l and/or HbA1c ≥ 48 mmol⁄mol (≥ 6.5%) for the following variables: current BMI, BMI in the early 20s (BMI(20y)), lifetime maximum BMI (BMI(max)), change between BMI in the early 20s and current BMI (ΔBMI(20y-cur)), change between BMI in the early 20s and maximum BMI (ΔBMI(20y-max)), and change between lifetime maximum and current BMI (ΔBMI(max-cur)).

RESULTS

The prevalence of undiagnosed diabetes was 3.3% (771/23252) among participants. BMI(max) , ΔBMI(20y-max) and current BMI (1-sd increments) were more strongly associated with diabetes than the other factors (multivariate odds ratio 1.58 [95% CI 1.47-1.70] in men and 1.65 [95% CI 1.43-1.90] in women for BMI(max) ; multivariate odds ratio 1.47 [95% CI 1.37-1.58] in men and 1.61 [95% CI 1.41-1.84] in women for ΔBMI(20y-max) ; multivariate odds ratio 1.47 [95% CI 1.36-1.58] in men and 1.63 [95% CI 1.40-1.89] in women for current BMI). The probability of having diabetes was markedly higher in those with both the highest tertile of BMI(max) and greatest ΔBMI(20y-max) ; however, a substantially lower likelihood of diabetes was observed among individuals with the lowest and middle tertiles of current BMI (< 24.62 kg/m² in men and < 22.54 kg/m² in women).

CONCLUSIONS

Lifetime maximum BMI and BMI changes from early adulthood were strongly associated with undiagnosed diabetes. Adding BMI history to people's current BMI would improve the identification of individuals with a markedly higher probability of having undiagnosed diabetes.

Role of sleep duration as a risk factor for Type 2 diabetes among adults of different ages in Japan: the Niigata Wellness Study

AIM

To compare the role of short sleep duration as a risk factor for diabetes among adults of different ages.

METHODS

The study enrolled 38987 Japanese individuals without diabetes, and the 8-year risk of developing diabetes attributable to different sleep durations (< 5.5 h, 5.5 to < 6.5 h, 6.5 to < 7.0 h, 7.0-7.5 h, > 7.5-8.0 h, or > 8.0 h) was assessed among individuals aged ≤ 45, 46-59 or ≥ 60 years.

RESULTS

During the 8-year follow-up period, 2085 individuals developed diabetes. Overall, individuals with a short sleep duration of < 5.5 h or 5.5 to < 6.5 h had, respectively, a 1.53-fold (95% CI 1.19, 1.97) or 1.25-fold (95% CI 1.10, 1.42) increased risk of diabetes as compared with those who had 7.0-7.5 h of sleep. A sleep duration of < 5.5 h or 5.5 to < 6.5 h was predictive of the development of diabetes among individuals aged ≤ 45 years, but not among those aged ≥ 60 years. With increasing age, the effect of short sleep duration on the risk of diabetes was attenuated.

CONCLUSIONS

Short sleep duration was predictive of diabetes among young or middle-aged Japanese adults but not among elderly individuals after age was considered. Managing habitual short sleep and the possible reasons for having such short sleep duration could be particularly important for young or middle-aged adults in the development of future diabetes.

Ghrelin signalling in β-cells regulates insulin secretion and blood glucose

Insulin secretion from pancreatic islet β-cells is stimulated by glucose. Glucose-induced insulin release is potentiated or suppressed by hormones and neural substances. Ghrelin, an acylated 28-amino acid peptide, was isolated from the stomach in 1999 as the endogenous ligand for the growth hormone (GH) secretagogue-receptor (GHS-R). Circulating ghrelin is produced predominantly in the stomach and to a lesser extent in the intestine, pancreas and brain. Ghrelin, initially identified as a potent stimulator of GH release and feeding, has been shown to suppress glucose-induced insulin release. This insulinostatic action is mediated by Gα(i2) subtype of GTP-binding proteins and delayed outward K⁺ (Kv) channels. Interestingly, ghrelin is produced in pancreatic islets. The ghrelin originating from islets restricts insulin release and thereby upwardly regulates the systemic glucose level. Furthermore, blockade or elimination of ghrelin enhances insulin release, which can ameliorate glucose intolerance in high-fat diet fed mice and ob/ob mice. This review focuses on the insulinostatic action of ghrelin, its signal transduction mechanisms in islet β-cells, ghrelin's status as an islet hormone, physiological roles of ghrelin in regulating systemic insulin levels and glycaemia, and therapeutic potential of the ghrelin-GHS-R system as the target to treat type 2 diabetes.

Food groups and weight gain in Japanese men

Identifying subjects at high risk of weight gain according to consumption of food groups is important for individualizing nutritional education, but prospective studies of this issue have been few. We determined whether intake of specific food groups could predict future weight gain. We evaluated data from health checkups on 1236 Japanese men aged 28 to 87 years in 2005 and 2006. Dietary intake was assessed by a 24-h dietary recall at baseline. Weight change was measured after 1 year. Weight increased in 44.7% (n = 553) of participants. Multivariate regression analysis involving many food groups showed a significant association between sugar intake and weight gain after adjustment for age, body mass index (BMI), total energy intake, alcohol, smoking and regular physical exercise (β = 0.22, P = 0.04). The effect of intake of 'fats and oils' was significant when adjusted for age and BMI, however, it became insignificant after adjustment for age, BMI and total energy intake. Intake of sugar, which was evaluated as a food group, was predictive of subsequent weight gain among Japanese men, even after adjustment for many confounders. This corroborates the evidence so far concerning the links between sugar intake and weight gain. Further long-term research is required to give robust recommendation to the public.

Quantitative relationship between body weight gain in adulthood and incident type 2 diabetes: a meta-analysis

This meta-analysis quantified the risk of type 2 diabetes mellitus (T2DM) preceded by body weight (BW) gain in the general population. Systematic literature searches retrieved 15 eligible studies. The BW gain was divided into early weight-gain, which was defined as BW gain from early adulthood (18-24 years of age) to cohort entry (≥25 years of age), and late weight-gain, which was defined as BW gain from cohort entry. The pooled relative risk (RR; 95% confidence interval [CI]) of T2DM for an increment of BW gain standardized into a 5-kg m(-2) increment in the body mass index (BMI) was 3.07 (2.49-2.79) for early weight-gain and 2.12 (1.74-2.58) for late weight-gain. When limiting analysis to studies that concurrently examined T2DM risk for current BMI (defined in both groups as BMI at cohort entry), a larger magnitude of T2DM risk was revealed for early weight-gain compared with current BMI (RR [95% CI], 3.38 [2.20-5.18] vs. 2.39 [1.58-3.62]), while there was little difference between late weight-gain (RR [95% CI], 2.21 [1.91-2.56]) and current BMI (RR [95% CI], 2.47 [1.97-3.30]). The meta-analysis suggested that BW gain was a quantifiable predictor of T2DM, as well as current obesity in adults. Particularly, BW gain in early rather than middle-to-late adulthood played an important role in developing T2DM.

Association of living alone with the presence of undiagnosed diabetes in Japanese men: the role of modifiable risk factors for diabetes: Toranomon Hospital Health Management Center Study 13 (TOPICS 13)

AIMS

To investigate whether living alone was associated with the presence of undiagnosed diabetes and whether this association could be attenuated by modifiable lifestyle habits.

METHODS

This cross-sectional study included 6400 Japanese men without a history of diagnosed diabetes. Individuals with currently undiagnosed diabetes were identified through fasting glucose concentration ≥7.0 mmol/l or HbA1c concentration ≥ 48 mmol⁄mol (≥ 6.5%). Effect modification was examined using body mass index, hypertension, history of dyslipidaemia, drinking habits, smoking habits, physical activity, vegetable intake, emotional stress and depressed mood.

RESULTS

Men who lived alone (n = 1098) had a significantly elevated odds ratio for having undiagnosed diabetes in an age-adjusted model (odds ratio 1.45, 95% CI 1.07, 1.96; P = 0.018). After adjustment for lifestyle factors, the association was slightly attenuated (odds ratio 1.40, 95% CI 1.02, 1.91; P = 0.036). After further adjustment for all factors mentioned above, living alone was still marginally significantly associated with the presence of undiagnosed diabetes (odds ratio 1.38, 95% CI 1.003, 1.90; P = 0.048). A significant association of living alone with the presence of undetected diabetes was particularly observed among men who were overweight, currently smoked and were physically inactive, or had any one of those three factors.

CONCLUSIONS

The association between undiagnosed diabetes and living alone can be partially influenced by modifiable lifestyle factors. Men who lived alone, especially those who did not engage in favourable lifestyle habits, were more likely to have undiagnosed diabetes. Such individuals have a higher probability of having undetected diabetic hyperglycaemia and would need to undergo glucose tests to identify the disease.

Leisure-time physical activity is a significant predictor of stroke and total mortality in Japanese patients with type 2 diabetes: analysis from the Japan Diabetes Complications Study (JDCS)

AIMS/HYPOTHESIS

Our aim was to clarify the association between leisure-time physical activity (LTPA) and cardiovascular events and total mortality in a nationwide cohort of Japanese diabetic patients.

METHODS

Eligible patients (1,702) with type 2 diabetes (mean age, 58.5 years; 47% women) from 59 institutes were followed for a median of 8.05 years. A comprehensive lifestyle survey including LTPA and occupation was performed using standardised questionnaires. Outcome was occurrence of coronary heart disease (CHD), stroke and total mortality. The adjusted HR and 95% CI were calculated by Cox regression analysis.

RESULTS

A significant reduction in HR in patients in the top (≥ 15.4 metabolic equivalents [MET] h/week) vs the bottom tertile (≤ 3.7 MET h/week) of LTPA, adjusted by age, sex and diabetes duration, was observed in stroke (HR 0.55, 95% CI 0.32, 0.94) and total mortality (HR 0.49, 95% CI 0.26, 0.91) but not in CHD (HR 0.77, 95% CI 0.48, 1.25). The HR for stroke became borderline significant or nonsignificant after adjustment for lifestyle or clinical variables including diet or serum lipids. The significantly reduced total mortality by LTPA was independent of these variables and seemed not to be, at least mainly, attributed to reduced cardiovascular disease.

CONCLUSIONS/INTERPRETATION

In Japanese persons with type 2 diabetes, LTPA of 15.4 MET h/week or more was associated with a significantly lower risk of stroke partly through ameliorating combinations of cardiovascular risk factors. It was also associated with significantly reduced total mortality but independently of cardiovascular risk factors or events. These findings, implying differences from Western diabetic populations, should be considered in the clinical management of East Asians with diabetes.

Low BMI at age 20 years predicts gestational diabetes independent of BMI in early pregnancy in Japan: Tanaka Women's Clinic Study

AIMS

Maternal obesity and weight gain since early adulthood are known predictors of gestational diabetes in Western countries. However, their impact has not been evaluated well in Asia, where mean BMI levels are generally lower than in Western countries. We therefore examined the associations of BMI at age 20 years and BMI change since age 20 years with the risk of gestational diabetes in Japanese pregnant women.

METHODS

Six hundred and twenty-four consecutive pregnant women without recognized diabetes before pregnancy, whose initial obstetric clinic visit was before 13 weeks' gestation, were prospectively observed. Weight at age 20 years was self-reported. Baseline height and weight measurements were obtained at the initial obstetric visit. Multivariate logistic regression analysis estimated the risk of incident gestational diabetes for BMI change since 20 years and BMI at age 20 years.

RESULTS

Twenty-eight women developed incident gestational diabetes. By multivariate logistic regression analysis that adjusted for maternal age, parity and baseline BMI, we observed a statistically significant inverse association between BMI at age 20 years and incidence of gestational diabetes (odds ratio 0.68, 95% CI 0.51-0.92). Similarly, when we assessed the association of BMI change since age 20 years, adjusted for maternal age and parity, BMI change was associated with an increased risk of gestational diabetes (odds ratio 1.26, 95% CI 1.03-1.53). When we focused on the threshold of risk of gestational diabetes, women with BMI at 20 years of less than 18 kg/m(2) had a 6.30-fold (2.26-17.59) greater risk than women with both BMI at age 20 years of 18 kg/m(2) or more and BMI change since age 20 years of less than 1.85.

CONCLUSIONS

Both low BMI at age 20 years and BMI change since age 20 years were significantly associated with increased risk of incident gestational diabetes.

Development of a new scoring system for predicting the 5 year incidence of type 2 diabetes in Japan: the Toranomon Hospital Health Management Center Study 6 (TOPICS 6)

AIMS/HYPOTHESIS

The aims of this study were to assess the clinical significance of introducing HbA(1c) into a risk score for diabetes and to develop a scoring system to predict the 5 year incidence of diabetes in Japanese individuals.

METHODS

The study included 7,654 non-diabetic individuals aged 40-75 years. Incident diabetes was defined as fasting plasma glucose (FPG) ≥7.0 mmol/l, HbA(1c) ≥6.5% (48 mmol/mol) or self-reported clinician-diagnosed diabetes. We constructed a risk score using non-laboratory assessments (NLA) and evaluated improvements in risk prediction by adding elevated FPG, elevated HbA(1c) or both to NLA.

RESULTS

The discriminative ability of the NLA score (age, sex, family history of diabetes, current smoking and BMI) was 0.708. The difference in discrimination between the NLA + FPG and NLA + HbA(1c) scores was non-significant (0.836 vs 0.837; p = 0.898). A risk score including family history of diabetes, smoking, obesity and both FPG and HbA(1c) had the highest discrimination (0.887, 95% CI 0.871, 0.903). At an optimal cut-off point, sensitivity and specificity were high at 83.7% and 79.0%, respectively. After initial screening using NLA scores, subsequent information on either FPG or HbA(1c) resulted in a net reclassification improvement of 42.7% or 52.3%, respectively (p < 0.0001). When both were available, net reclassification improvement and integrated discrimination improvement were further improved at 56.7% (95% CI 47.3%, 66.1%) and 10.9% (9.7%, 12.1%), respectively.

CONCLUSIONS/INTERPRETATION

Information on HbA(1c) or FPG levels after initial screening by NLA can precisely refine diabetes risk reclassification.

High normal HbA(1c) levels were associated with impaired insulin secretion without escalating insulin resistance in Japanese individuals: the Toranomon Hospital Health Management Center Study 8 (TOPICS 8)

AIMS

We aimed to characterize the association of insulin resistance, impaired insulin secretion and β-cell dysfunction in relation to HbA(1c) levels in a non-diabetic range in Japanese individuals without clinically diagnosed diabetes.

METHODS

This cross-sectional study included 1444 individuals without a history of outpatient treatment of diabetes or use of insulin or oral hypoglycaemic agents. The homeostasis model assessment of insulin resistance and beta-cell function, insulinogenic index, Matsuda index and disposition index were calculated using data from 75-g oral glucose tolerance tests and compared across quintile (Q) categories of HbA(1c) levels.

RESULTS

Fasting plasma glucose and 30-min and 60-min plasma glucose (PG) levels were significantly higher when HbA(1c) exceeded 36 mmol/mol (5.4%). A HbA(1c) concentration of 36-37 mmol/mol (5.4-5.5%) (Q3) was significantly associated with a 15% lower homeostasis model assessment of β-cell function value and 31% lower insulinogenic index value compared with HbA(1c) ≤ 32 mmol/mol (≤ 5.1%) (Q1) (P <0.01). Further, a HbA(1c) concentration of 38-40 mmol/mol (5.6-5.8%) (Q4) was associated with 17% (P <0.01) and 24% (P <0.05) reductions in those indexes, respectively. However, the homeostasis model assessment of insulin resistance was not significantly elevated and the Matsuda index was not significantly lower unless HbA(1c) exceeded 41 mmol/mol (5.9%). Individuals with HbA(1c) ≥ 41 mmol/mol (≥ 5.9%) (Q5) had a 69% lower disposition index than those with a HbA(1c) concentration of ≤ 32 mmol/mol (≤ 5.1%) (Q1).

CONCLUSIONS

Elevated HbA(1c) levels ≥ 41 mmol/mol (≥ 5.9%) were associated with substantial reductions in insulin secretion, insulin sensitivity and β-cell dysfunction in Japanese individuals not treated for diabetes. High normal HbA(1c) levels of 36-40 mmol/mol (5.4-5.8%) were also associated with impaired insulin secretion without marked insulin resistance in Japanese individuals.

Screening for pre-diabetes to predict future diabetes using various cut-off points for HbA(1c) and impaired fasting glucose: the Toranomon Hospital Health Management Center Study 4 (TOPICS 4)

AIM

To evaluate various screening criteria for pre-diabetes to identify which combination of impaired fasting glucose and elevated HbA(1c) values performs most effectively in predicting future diabetes in a large cohort of Japanese individuals.

METHODS

The study included 4670 men and 1571 women without diabetes (diabetes: fasting plasma glucose ≥ 7.0 mmol/l, HbA(1c) ≥ 48 mmol/mol (≥ 6.5%), or self-reported clinician-diagnosed diabetes). Pre-diabetes was diagnosed by a combination of impaired fasting glucose (fasting plasma glucose 5.6-6.9 mmol/l or 6.1-6.9 mmol/l) and elevated HbA(1c) [39-46 mmol/mol (5.7-6.4%) or 42-46 mmol/mol (6.0-6.4%)].

RESULTS

During a 5-year follow-up, 338 incident cases of diabetes occurred. The combination of HbA(1c) 39-46 mmol/mol (5.7-6.4%) and fasting plasma glucose 5.6-6.9 mmol/l yielded the highest sensitivity (86%) and generated a large population-attributable per cent risk (78%) for predicting development of diabetes. Among individuals classified as having pre-diabetes by any of the four combined criteria, 20.5-32.0% reverted to the normoglycaemic state as having neither elevated HbA(1c) nor impaired fasting glucose at the last follow-up examination. At 5.6 years after the baseline examination, however, pre-diabetic individuals who fulfilled both HbA(1c) 42-46 mmol/mol (6.0-6.4%) and fasting plasma glucose 6.1-6.9 mmol/l had a 100% cumulative risk of developing diabetes.

CONCLUSIONS

The combination of HbA(1c) 39-46 mmol/mol (5.7-6.4%) and fasting plasma glucose 5.6-6.9 mmol/l would have the best performance in reducing the likelihood of missing future cases of diabetes. Identifying pre-diabetic individuals who strictly fulfil HbA(1c) 42-46 mmol/mol (6.0-6.4%) and fasting plasma glucose 6.1-6.9 mmol/l would predict definite progression to diabetes.

HbA(1c) variability and the development of microalbuminuria in type 2 diabetes: Tsukuba Kawai Diabetes Registry 2

AIMS/HYPOTHESIS

The aim of this study was to examine the association between HbA(1c) variability and the development of microalbuminuria as defined by an albumin/creatinine ratio ≥ 3.4 mg/mmol (≥ 30 mg/g) in at least two of three consecutive urine samples in Japanese patients with type 2 diabetes.

METHODS

HbA(1c) level was measured in 812 serially registered normoalbuminuric adults aged 21-79 years with type 2 diabetes. After registration, a 1-year period to establish baseline values for mean HbA(1c) and HbA(1c) variability (measured as the intrapersonal SD of serially collected HbA(1c)) was decided upon. The association between HbA(1c) variability and the development of microalbuminuria was determined by Cox regression analysis after adjustment for other risk factors for microalbuminuria.

RESULTS

Microalbuminuria occurred in 193 patients during the observation period of (mean ± SD) 4.3 ± 2.7 years. Even after adjustment for mean HbA(1c), HbA(1c) variability was a significant predictor of microalbuminuria independently of the mean HbA(1c); the HR for every 1% (95% CI) increase in mean HbA(1c) was 1.22 (1.06, 1.40) (p = 0.005), and that for HbA(1c) variability was 1.35 (1.05, 1.72) (p = 0.019). The effects of these two variables were quite similar when 1 SD was used; the HR for every 1 SD increase (95% CI) in HbA(1c) was 1.23 (1.07, 1.43) (p = 0.005), and that for HbA(1c) variability was 1.20 (1.03, 1.39) (p = 0.019).

CONCLUSIONS/INTERPRETATION

HbA(1c) variability affects the development of microalbuminuria independently of mean HbA(1c) in type 2 diabetes. Further studies should be performed to evaluate the influence of HbA(1c) variability on other complications and in individuals of other ethnicities with type 2 diabetes.

Impact of psychological stress caused by the Great East Japan Earthquake on glycemic control in patients with diabetes

We examined the relationship between psychological stress and the worsening of glycemic control in diabetic patients at the time of the Great East Japan Earthquake. HbA1c levels in diabetic patients before and after the disaster were evaluated with the General Health Questionnaire (GHQ) and other questions including those on changes in diet, exercise, psychological stress and drug intake in 320 consecutive diabetic patients who had been followed in a diabetes clinic. Logistic regression analysis revealed that the total GHQ scores (odds ratio [OR] 1.03 [95% confidence interval 1.01-1.06]; p<0.01) and interruption of drug intake (OR 4.48 [1.57-12.7]; p=0.01) were independently associated with worsening of glycemic control defined as an increase in the HbA1c level equal to or greater than 0.5%. Among the scores on the GHQ, those for somatic symptoms (OR 1.18 [1.01-1.38]; p=0.03) and sleep disturbances or anxiety (OR 1.26 [1.08-1.46]; p<0.01) were independently associated with glycemic control. These results suggest that psychological stress during a disaster has independent effects on worsening of glycemic control.

Chronic kidney disease categories and renal-cardiovascular outcomes in type 2 diabetes without prevalent cardiovascular disease: a prospective cohort study (JDDM25)

AIMS/HYPOTHESIS

In type 2 diabetic patients at low risk for cardiovascular disease (CVD), the relationship between the clinical course of nephropathy by stage of chronic kidney disease (CKD) and onset of CVD remains unclear. Clarification of this relationship is important for clinical decision-making for both low- and high-risk diabetic patients.

METHODS

This 4 year prospective study enrolled 2,954 type 2 diabetic patients with no prevalent CVD, and serum creatinine <176.8 μmol/l. The risk for CVD onset (non-fatal and fatal CVD and stroke, and peripheral arterial disease) was assessed according to CKD stage categorised by urinary albumin-to-creatinine ratio (ACR; mg/mmol) and estimated GFR (eGFR; ml min(-1) 1.73 m(-2)). Association of progression from 'no CKD' stage (ACR <3.5 mg/mmol and eGFR ≥ 90 ml min(-1) 1.73 m(-2)) with risk for CVD onset was also evaluated.

RESULTS

During follow-up (median 3.8 years), 89 CVD events occurred. Compared with patients with 'no CKD' as reference, those with ACR ≥ 35.0 mg/mmol with co-existing eGFR 60-89 ml min(-1) 1.73 m(-2) or <60 ml min(-1) 1.73 m(-2) showed increased risk for CVD onset, whereas those with eGFR ≥ 90 ml min(-1) 1.73 m(-2) did not. Those with ACR <3.5 mg/mmol and eGFR <60 ml min(-1) 1.73 m(-2) did not show any increased risk. Among patients with 'no CKD' stage at baseline, those who progressed to ACR ≥ 3.5 mg/mmol during follow-up showed an increased risk compared with those who did not, whereas those who progressed to eGFR <90 ml min(-1) 1.73 m(-2) did not have increased risk.

CONCLUSIONS/INTERPRETATION

The risk for CVD was associated with progression of albuminuria stage rather than eGFR stage in type 2 diabetic patients at relatively low risk for CVD.

Low incidence of cardiovascular events in Japanese patients with Type 2 diabetes in primary care settings: a prospective cohort study (JDDM 20)

AIMS

To investigate whether a reduced incidence of cardiovascular disease in Type 2 diabetes can be achieved in a newly recruited cohort following the recently advanced concept of multifactorial treatment and followed in primary care settings as compared with earlier cohorts.

METHODS

A prospective study was performed in primary care settings at multiple clinics nationwide in the Japan Diabetes Clinical Data Management (JDDM) study group. Subjects were 2984 patients with Type 2 diabetes without prevalent cardiovascular disease. The main outcome measure was the first event of non-fatal or fatal coronary heart disease, ischaemic stroke or peripheral artery disease, and the incidence was compared with other representative cohorts.

RESULTS

There were 90 cardiovascular events over 10,827 person-years of follow-up with a dropout rate of 6%. The incidences (per 1000 person-years, 95% confidence interval) of composite, coronary heart disease, ischaemic stroke and peripheral artery disease in the JDDM study were 8.3 (6.6-10.0), 4.4 (3.2-5.6), 3.1 (2.1-4.2), and 0.7 (0.2-1.2), respectively. Each incidence was lowest in the JDDM study compared with other cohorts (P < 0.01 vs. each cohort). In the JDDM study, significant variables predictive of the occurrence of a cardiovascular event were age, duration of diabetes, HbA(1c), HDL cholesterol and urinary albumin.

CONCLUSION

The novel finding of low cardiovascular disease occurrence in this study may be conferred by the feasibility at primary care settings for providing patients with Type 2 diabetes with favourable control of blood glucose, blood pressure and lipids, coupled with unique ethnicity/country factors.

Incidence and progression of diabetic retinopathy in Japanese adults with type 2 diabetes: 8 year follow-up study of the Japan Diabetes Complications Study (JDCS)

AIMS/HYPOTHESIS

The aim of this study was to determine the incidence and progression rates of diabetic retinopathy and their associations in Japanese individuals with type 2 diabetes.

METHODS

This is a part of the Japan Diabetic Complications Study (JDCS), a multi-centred randomised trial of type 2 diabetes patients aged 40-70 years with an 8 year follow-up. There were 1,221 patients without diabetic retinopathy at baseline; incidence of diabetic retinopathy was defined as the development of any diabetic retinopathy. There were 410 patients with mild non-proliferative diabetic retinopathy at baseline; progression of diabetic retinopathy was defined as the development of severe non-proliferative diabetic retinopathy or proliferative diabetic retinopathy. We used multivariate proportional Cox hazard models, and generalised additive models were also applied to identify potential threshold effect.

RESULTS

The incidence and progression rate of diabetic retinopathy was 38.3/1,000 person-years and 21.1/1,000 person-years, respectively. Higher HbA(1c) (adjusted HR [aHR] per 1% [10.9 mmol/mol] 1.36 [95% CI 1.28-1.45]), longer duration of diabetes (aHR per 5 year period 1.26 [95% CI 1.17-1.35]), higher systolic blood pressure (aHR per +10 mmHg 1.01 [95% CI 1.00-1.02]) and higher body mass index (aHR per 1 kg/m(2) 1.05 [95% CI 1.00-1.09]) were associated with incident diabetic retinopathy. The association between HbA(1c) and incident diabetic retinopathy was linear; the association with duration of diabetes increased rapidly between 5 and 10 years. Higher HbA(1c) was also associated with progression of diabetic retinopathy (aHR per 1% [10.9 mmol/mol] 1.66 [95% CI 1.41-1.96]).

CONCLUSIONS

Observed incidence and progression rates of diabetic retinopathy seemed lower than that in western populations. HbA(1c) was the only factor associated with both incidence and progression of diabetic retinopathy. The strength of the association between duration of diabetes and incidence of diabetic retinopathy increased rapidly during a period of 5 to 10 years duration of diabetes.

TRIAL REGISTRATION

C000000222 ( www.umin.ac.jp )

FUNDING

This study is supported by the Ministry of Health, Labour and Welfare, Japan.

Low transition rate from normo- and low microalbuminuria to proteinuria in Japanese type 2 diabetic individuals: the Japan Diabetes Complications Study (JDCS)

AIMS/HYPOTHESIS

The aim of the study was to determine the transition rate and factors associated with the progression of normo- and low microalbuminuria to diabetic nephropathy (overt proteinuria).

METHODS

For 8 years we prospectively observed 1,558 Japanese patients with type 2 diabetes mellitus whose basal urinary albumin:creatinine ratio (UACR) had been measured as <17.0 mg/mmol at entry. The incidence of nephropathy (UACR >33.9 mg/mmol) was determined by measuring UACR twice a year.

RESULTS

Progression to nephropathy occurred in 74 patients. The annual transition rate was 0.67%, and was substantially higher for the low-microalbuminuric group than for the normoalbuminuric group (1.85% and 0.23%, respectively; hazard ratio for the low-microalbuminuric group 8.45, p < 0.01). The hazard ratio for an HbA(1c) of 7-9% or ≥9% was 2.72 (p < 0.01) or 5.81 (p < 0.01) relative to HbA(1c) <7.0%, respectively. In comparison with individuals with a systolic blood pressure (SBP) of <120 mmHg, the hazard ratios for patients with an SBP of 120-140 mmHg or ≥140 mmHg were 2.31 (p = 0.06) and 3.54 (p < 0.01), respectively. Smoking also affected progression to proteinuria (hazard ratio 1.99, p < 0.01). In contrast, 30.3% of the low-microalbuminuric group returned to normoalbuminuria (i.e. were in remission).

CONCLUSIONS/INTERPRETATION

These results suggest that if patients with type 2 diabetes mellitus are receiving treatment from diabetologists for hyperglycaemia and hypertension when they are in the early stages of nephropathy (i.e. normo- or low microalbuminuria), their rate of transition to proteinuria is considerably lowered, and that differentiating patients with low microalbuminuria from those with high microalbuminuria might be clinically useful.

TRIAL REGISTRATION

UMIN Clinical Trials Registry C000000222.

Low serum potassium levels and risk of type 2 diabetes: the Toranomon Hospital Health Management Center Study 1 (TOPICS 1)

AIMS/HYPOTHESIS

Evidence has suggested that low serum potassium concentrations decrease insulin secretion, leading to glucose intolerance, and that hypokalaemia induced by diuretics increases the risk for diabetes in hypertensive individuals. However, no prospective study has investigated the association between serum potassium and the development of type 2 diabetes in a healthy cohort comprised of Asian individuals not being administered antihypertensive medications. This study aimed to investigate whether low serum potassium is associated with increased risk of type 2 diabetes in apparently healthy Japanese men.

METHODS

We followed 4,409 Japanese men with no history of diabetes, use of antihypertensives, renal dysfunction or liver dysfunction (mean ± SD age, 48.4 ± 8.4 years). Cox proportional hazards regression was used to estimate HRs for incident diabetes (fasting plasma glucose level ≥ 7.0 mmol/l, HbA(1c) ≥ 6.5% or self-reported) including serum potassium concentration as either a categorical or a continuous variable.

RESULTS

During a 5 year follow-up, 250 individuals developed type 2 diabetes. The lowest tertile of serum potassium (2.8-3.9 mmol/l) was independently associated with the development of diabetes after adjustment for known predictors (HR 1.57 [95% CI, 1.15-2.15]) compared with the highest tertile (4.2-5.4 mmol/l). Every 0.5 mmol/l lower increment in the baseline serum potassium level was associated with a 45% (12-87%) increased risk of diabetes.

CONCLUSIONS/INTERPRETATION

Mild to moderately low serum potassium levels, within the normal range and without frank hypokalaemia, could be predictive of type 2 diabetes in apparently healthy Japanese men.

Nifedipine, a calcium-channel blocker, attenuated glucose intolerance and white adipose tissue dysfunction in type 2 diabetic KK-A(y) mice

BACKGROUND

To explore the metabolic actions of nifedipine on diabetes, we examined glucose intolerance and white adipose tissue changes in type 2 diabetic KK-A(y) mice.

METHODS

Male KK-A(y) mice were treated with nifedipine (1.5 mg/kg/day in lab chow) for 5 weeks, which did not affect blood pressure or feeding of KK-A(y) mice.

RESULTS

After treatment with nifedipine, body weight tended to decrease and the weight of white adipose tissue was reduced. Without food restriction, nifedipine decreased plasma insulin level, while plasma glucose level tended to decrease. In oral glucose tolerance test, nifedipine suppressed the increase in glucose level after a glucose load without affecting plasma insulin concentration. Nifedipine also improved the result of insulin tolerance test. In white adipose tissue, nifedipine increased adipocyte number and the expression of peroxisome proliferator-activated receptor-γ (PPARγ) and adipocyte fatty acid-binding protein related to adipocyte differentiation. In addition, expression of adiponectin, insulin receptor, insulin receptor substrate-1, and glucose transporter type-4 was also increased by nifedipine. Nifedipine also increased the expression of NO synthase in white adipose tissue. Nifedipine did not affect expression of angiotensin II type 1 (AT₁) and type 2 (AT₂) receptors in white adipose tissue. Such changes in white adipose tissue were apparent in retroperitoneal adipose tissue. Nifedipine did not change the expression of angiotensin receptors, renin receptor, and angiotensinogen in white adipose tissue. Moreover, nifedipine attenuated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and increased superoxide dismutase (SOD) activity in white adipose tissue.

CONCLUSION

These results suggest that nifedipine can enhance insulin sensitivity and reduce white adipose tissue, possibly related to stimulation of adipocyte differentiation.

Oxygenomics in environmental stress

Environmental stressors such as chemicals and physical agents induce various oxidative stresses and affect human health. To elucidate their underlying mechanisms, etiology and risk, analyses of gene expression signatures in environmental stress-induced human diseases, including neuronal disorders, cancer and diabetes, are crucially important. Recent studies have clarified oxidative stress-induced signaling pathways in human and experimental animals. These pathways are classifiable into several categories: reactive oxygen species (ROS) metabolism and antioxidant defenses, p53 pathway signaling, nitric oxide (NO) signaling pathway, hypoxia signaling, transforming growth factor (TGF)-beta bone morphogenetic protein (BMP) signaling, tumor necrosis factor (TNF) ligand-receptor signaling, and mitochondrial function. This review describes the gene expression signatures through which environmental stressors induce oxidative stress and regulate signal transduction pathways in rodent and human tissues.

Long-term lifestyle intervention lowers the incidence of stroke in Japanese patients with type 2 diabetes: a nationwide multicentre randomised controlled trial (the Japan Diabetes Complications Study)

AIMS/HYPOTHESIS

The aim of the study was to clarify whether a therapeutic intervention focused on lifestyle modification affected the incidence of vascular complications in patients with established diabetes.

METHODS

A total of 2,033 eligible Japanese men and women aged 40-70 years with type 2 diabetes from 59 institutes were randomised to a conventional treatment group (CON), which continued to receive the usual care, and a lifestyle intervention group (INT), which received education on lifestyle modification regarding dietary habits, physical activities and adherence to treatment by telephone counselling and at each outpatient clinic visit, in addition to the usual care. Randomisation and open-label allocation were done by a central computer system. Primary analysis regarding measurements of control status and occurrence of macro- and microvascular complications was based on 1,304 participants followed for an 8 year period.

RESULTS

Although status of control of most classic cardiovascular risk factors, including body weight, glycaemia, serum lipids and BP, did not differ between groups during the study period, the incidence of stroke in the INT group (5.48/1,000 patient-years) was significantly lower than in the CON group (9.52/1,000 patient-years) by Kaplan- Meier analysis (p=0.02 by logrank test) and by multivariate Cox analysis (HR 0.62, 95% CI 0.39-0.98, p=0.04). The incidence of CHD, retinopathy and nephropathy did not differ significantly between groups. Lipoprotein(a) was another significant independent risk factor for stroke.

CONCLUSIONS/INTERPRETATION

These findings suggest that lifestyle modification had limited effects on most typical control variables, but did have a significant effect on stroke incidence in patients with established type 2 diabetes.

CLINICAL TRIAL REGISTRATION

UMIN-CTR C000000222

FUNDING

The Ministry of Health, Labour and Welfare, Japan

Reduced GFR and microalbuminuria are independently associated with prevalent cardiovascular disease in Type 2 diabetes: JDDM study 16

AIMS

We investigated whether a reduced estimated glomerular filtration rate (eGFR) was associated with cardiovascular disease (CVD) prevalence, independent of the effect of microalbuminuria in patients with diabetes.

METHODS

In a multicentre, large-scale cohort including 3002 Japanese patients with Type 2 diabetes without macroalbuminuria, the relationship of a reduced eGFR and microalbuminuria with CVD was investigated.

RESULTS

Of those patients, 4.8% had a reduced eGFR and microalbuminuria, 12.7% had a reduced eGFR without microalbuminuria and 18.7% had microalbuminuria but normal eGFR. A reduced eGFR and microalbuminuria were each associated with a doubling of the prevalence of CVD. Compared with patients with no microalbuminuria/normal eGFR [odds ratio (OR) 1.0], the OR for CVD was significantly higher in those with a reduced eGFR without microalbuminuria (OR 1.97) and similarly higher in those with microalbuminuria without a reduced eGFR (OR 1.85). The OR was highest in those with both a reduced eGFR and microalbuminuria (OR 3.97, 95% confidence interval 2.55-6.20). The OR for CVD remained significant after adjustments for age, sex, hypertension, dyslipidaemia, smoking, body mass index, glycated haemoglobin and the duration of diabetes, and remained significant if the cut-off point for microalbuminuria was set at the median albumin : creatinine ratio (13.7 mg/g creatinine). In patients without microalbuminuria, a reduced eGFR was associated with CVD only in the older and male groups.

CONCLUSION

A reduced eGFR and the presence of microalbuminuria were each associated with a near doubling of the prevalence of CVD, independently of traditional CVD risk factors and glycaemic control in patients with Type 2 diabetes.

The Regulation of Adiponectin Receptors Expression by Acute Exercise in Mice

Adiponectin is an adipocyte-derived factor that plays a pivotal role in lipid and glucose metabolism. Recently, two types of adiponectin receptors (AdipoR1 and AdipoR2) were identified. While, although physical exercise is useful for improving insulin sensitivity, the effect of physical exercise on adiponectin and adiponectin receptors are still unclear. In present study, we investigated whether acute exercise affects the plasma adiponectin concentration and expression of adiponectin receptor in skeletal muscle and liver in healthy mice C57BL/6. Following an acute exercise, plasma glucose, insulin, FFA, and adiponectin were measured. The mRNA levels of AdipR1 and AdipoR2 were also analyzed. Although acute exercise did not significantly change plasma adiponectin concentration at 2 hours or 18 hours after the exercise compared with control group, the expression levels of AdipoR1 significantly increased in both skeletal muscle (2H: 1.2-fold, p=0.0423, 18H: 1.4-fold, p=0.0006) and liver (2H: 1.3-fold, p=0.0448) compared with control group. In contrast, the level of AdipoR2 mRNA was decreased in skeletal muscle (18H: 0.8-fold, p=0.027) and liver (2H: 0.9-fold, p=0.1551) compared with control group. Additionally, the transcription factor Foxo1 mRNA expression level was also significantly increased in skeletal muscle (2H: 10-fold, p=0.0001, 18H: 3-fold, p=0.0424) and liver (2H: 2-fold, p=0.002, 18H: 2-fold, p=0.0014) compared with control group by the acute exercise. These findings suggest that acute exercise affects the expression level of adiponectin receptors, and an increase of Foxo1 expression might be relative to regulate adiponectin receptors.

Leptin resistance conferred by a combination of single nucleotide polymorphism and the adoption of a Western lifestyle in urban areas of Thailand

OBJECTIVES

An increasing number of lifestyle disorders have emerged in response to the rapid urbanization that has occurred in Thailand. Recently, leptin resistance has been nominated as a possible marker for the onset of metabolic disorders in Asian countries. The research aimed to assess the relationship between leptin-resistance and environmental and/or genetic factors by comparing urban and rural inhabitants in Thailand.

METHODS

A total of 212 age- and sex-matched subjects from an urban area (Bangkok) and from rural areas (Sai Noi) participated in the study. Anthropometric measurements, blood biochemistry, single nucleotide polymorphism analyses, and interviews concerning lifestyles and dietary habits were conducted individually. Backward elimination multiple regression analyses and least trimmed sum of square methods were used to estimate the effects of possible factors.

RESULTS

A transition of staple food from rice to bread (decreased rice intake; p < 0.01 and increased bread intake; p < 0.05) was significant in urban areas. Leptin levels were higher in urban groups, with a significant difference in women (p < 0.001 in women and p = 0.06 in men), but not in men. Predictors selected for leptin-resistance in women were genotypes of UCP2, PPARg2, bread intake, living area, and smoking habit (r = 0.510); in men, genotypes of UCP2 and UCP3p, smoking habit, and rice intake (r = 0.315).

CONCLUSIONS

Urban women with del/del type of UCP2 exhibited significant leptin resistance. A combination of urbanization and UCP2 genotype were considered to be responsible.

Pyruvate decarboxylase encoded by the PDC1 gene contributes, at least partially, to the decarboxylation of alpha-ketoisocaproate for isoamyl alcohol formation in Saccharomyces cerevisiae

Isoamyl alcohol is an important flavor component of yeast-fermented alcoholic beverages. To identify the enzyme and gene involved in the decarboxylation of alpha-ketoisocaproate (alpha-KIC) for isoamyl alcohol formation, the enzyme was partially purified and analyzed by mass spectrometry. The pyruvate decarboxylase encoded by the PDC1 gene was considered a likely candidate enzyme. Genetic analysis showed that the activity of alpha-KIC decarboxylase and production of isoamyl alcohol partially decreased in a pdc1 null mutant and increased in a transformant with a multi-copy plasmid carrying the PDC1 gene. These results indicate that pyruvate decarboxylase encoded by the PDC1 gene contributes, at least partially, to the decarboxylation of alpha-KIC for isoamyl alcohol formation.

Pancreatic beta cell senescence contributes to the pathogenesis of type 2 diabetes in high-fat diet-induced diabetic mice

AIMS/HYPOTHESIS

During the pathogenesis of type 2 diabetes insulin resistance causes compensatory proliferation of beta cells. As beta cells have a limited replication potential, this compensatory proliferation might accelerate cellular senescence and lead to diabetes. We examined the cellular senescence of beta cells after proliferation during lipoglucotoxicity.

METHODS

Senescence-associated markers in beta cells were examined in nutrient-induced diabetic C57BL/6J mice that were fed a high-fat diet. After 4 and 12 months of the high-fat diet, intraperitoneal glucose tolerance tests (IPGTTs) and histochemical analyses of Ki-67, p38, senescence-associated beta-galactosidase, and beta cell mass were performed.

RESULTS

At 4 months, the AUC for plasma insulin levels during the IPGTT (AUC(insulin)) was higher, beta cell mass was 3.1-fold greater, and the proliferation of beta cells was 2.2-fold higher than in the control group. However, at 12 months, AUC(insulin) declined, the frequency of Ki-67-positive beta cells decreased to one-third that of the control group, and the senescence-associated, beta-galactosidase-positive area increased to 4.7-fold that of the control group. Moreover, small amounts of p38, which is induced by oxidative stress and mediates cellular senescence, were found in beta cells from the high-fat diet group, but not in beta cells from the control group. Furthermore, the senescence-associated, beta-galactosidase-positive area in the high-fat diet group had a highly significant negative correlation with AUC(insulin) (r=-0.852, p<0.01).

CONCLUSIONS/INTERPRETATION

Beta cell senescence occurred in diet-induced type 2 diabetes and led to insufficient insulin release. These findings suggest that cellular senescence contributes to the pathogenesis of diet-induced diabetes.