Establishment of a reference interval for glycated albumin based on medical check-up data from multiple medical institutions.

Objectives: Data were collected to establish a reference interval for glycated albumin (GA), as well as to calculate a cutoff value for diagnosing diabetes mellitus and the GA level corresponding to a 75-g oral glucose tolerance test (OGTT) 2 h plasma glucose (2h-PG) level of 200 mg/dL.Methods: This study involved 1,843 subjects who were undergoing medical check-ups at several medical institutions and whose HbA1c and GA levels had been measured by OGTT.Results: The GA reference interval that was calculated based on the data obtained from study subjects with normal glucose tolerance was 12.1-17.1%. Using standardized major axis regression, the levels that corresponded to an OGTT 2h-PG level of 11.1 mmol/L were a GA level of 17.5% and an HbA1c level of 47.5 mmol/mol. A receiver-operating characteristic curve analysis was used to calculate the points at which sensitivity and specificity matched as the cutoff values, and the results yielded a GA level of 15.0% (sensitivity 69.3%).Conclusions: The GA reference interval was calculated to be 12.1-17.1%. We propose a GA level of 17.4% as a cutoff value to diagnose diabetes mellitus and a GA level of 15.0% as a screening cutoff value for diabetes mellitus, taking previous reports into account.

Development of a Novel Nutrition-Related Multivariate Biomarker for Mild Cognitive Impairment Based on the Plasma Free Amino Acid Profile.

Nutritional epidemiology has shown the importance of protein intake for maintaining brain function in the elderly population. Mild cognitive impairment (MCI) may be associated with malnutrition, especially protein intake. We explored blood-based biomarkers linking protein nutritional status with MCI in a multicenter study. In total, 219 individuals with MCI (79.5 ± 5.7 year) from 10 institutions and 220 individuals who were cognitively normal (CN, 76.3 ± 6.6 year) in four different cities in Japan were recruited. They were divided into the training (120 MCI and 120 CN) and validation (99 MCI and 100 CN) groups. A model involving concentrations of PFAAs and albumin to discriminate MCI from CN individuals was constructed by multivariate logistic regression analysis in the training dataset, and the performance was evaluated in the validation dataset. The concentrations of some essential amino acids and albumin were significantly lower in MCI group than CN group. An index incorporating albumin and PFAA discriminated MCI from CN participants with the AUC of 0.705 (95% CI: 0.632-0.778), and the sensitivities at specificities of 90% and 60% were 25.3% and 76.8%, respectively. No significant association with BMI or APOE status was observed. This cross-sectional study suggests that the biomarker changes in MCI group may be associated with protein nutrition.

Decreased circulating branched-chain amino acids are associated with development of Alzheimer's disease in elderly individuals with mild cognitive impairment.

Background: Nutritional epidemiology has shown that inadequate dietary protein intake is associated with poor brain function in the elderly population. The plasma free amino acid (PFAA) profile reflects nutritional status and may have the potential to predict future changes in cognitive function. Here, we report the results of a 2-year interim analysis of a 3-year longitudinal study following mild cognitive impairment (MCI) participants. Method: In a multicenter prospective cohort design, MCI participants were recruited, and fasting plasma samples were collected. Based on clinical assessment of cognitive function up to 2 years after blood collection, MCI participants were divided into two groups: remained with MCI or reverted to cognitively normal ("MCI-stable," N = 87) and converted to Alzheimer's disease (AD) ("AD-convert," N = 68). The baseline PFAA profile was compared between the two groups. Stratified analysis based on apolipoprotein E ε4 (APOE ε4) allele possession was also conducted. Results: Plasma concentrations of all nine essential amino acids (EAAs) were lower in the AD-convert group. Among EAAs, three branched-chain amino acids (BCAAs), valine, leucine and isoleucine, and histidine (His) exhibited significant differences even in the logistic regression model adjusted for potential confounding factors such as age, sex, body mass index (BMI), and APOE ε4 possession (p < 0.05). In the stratified analysis, differences in plasma concentrations of these four EAAs were more pronounced in the APOE ε4-negative group. Conclusion: The PFAA profile, especially decreases in BCAAs and His, is associated with development of AD in MCI participants, and the difference was larger in the APOE ε4-negative population, suggesting that the PFAA profile is an independent risk indicator for AD development. Measuring the PFAA profile may have importance in assessing the risk of AD conversion in the MCI population, possibly reflecting nutritional status. Clinical trial registration: [https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000025322], identifier [UMIN000021965].

Does Glycated Albumin Increase with Body Weight Reduction in Obese Non-Diabetic Subjects?

We reported that the body mass index (BMI) may exert a negative effect on glycated albumin (GA) in non-diabetic subjects and patients with type 2 diabetes mellitus. In addition, we suggested a mechanism in which chronic inflammation in obesity may enhance albumin catabolism, leading to a decrease in GA levels for non-diabetic subjects. In the present study, we examined whether GA levels increased with body weight reduction in obese, non-diabetic subjects. Among the subjects who underwent complete medical checkups in 2010 and in 2015, 101 subjects with BMIs of 25 kg/m2 or higher, without diabetes mellitus in 2010 were included in this study. Correlations of changes in BMI for five years (ΔBMI) with changes in various clinical laboratory test values [ΔC-reactive protein (CRP), ΔGA, ΔHbA1c, Δfasting plasma glucose (FPG), ΔGA/HbA1c and ΔGA/FPG] were investigated. ΔBMI significantly and positively correlated with ΔCRP, while ΔBMI did not significantly correlate with ΔGA. ΔBMI significantly and positively correlated with ΔHbA1c and ΔFPG. Furthermore, ΔBMI showed significant negative correlations with ΔGA/HbA1c and ΔGA/FPG. GA levels did not increase with body weight reduction in obese non-diabetic subjects. Such a phenomenon might be considered the result when the positive control of GA levels through decreases in chronic inflammation due to body weight reduction was counterbalanced by the negative control of GA levels through improvement in glucose tolerance.

A multicentre clinical validation of AminoIndex Cancer Screening (AICS).

AminoIndex Cancer Screening (AICS) is a novel cancer screening test based on plasma free amino acid (PFAA) levels. This system categorises subjects as rank A, B, or C in order of increasing probability of each cancer incidence. The current study aimed to validate the potential of AICS for cancer detection. AICS values were determined from the PFAA levels in subjects examined at Chiba Cancer Center Cohort, Mitsui Memorial Hospital, and Saihaku Hospital, and the cancer incidence was investigated. The sensitivities of rank C for cancer diagnosis within 1 year after AICS examination were 83.3% (10/12) for gastric, 50.0% (2/4) for lung, 46.2% (6/13) for colorectal, 50.0% (8/16) for prostate, 43.8% (7/16) for breast, and 50.0% (1/2) for uterine/ovarian cancer. The total cancer detection rate via AICS was 0.33% (34/10,245). The sensitivities during the maximum follow-up period of 6.2 years were 51.7% (15/29) for gastric, 18.2% (2/11) for lung, 28.6% (8/28) for colorectal, 36.4% (8/22) for prostate, 29.0% (9/31) for breast, and 33.3% (2/6) for uterine/ovarian cancers. In conclusion, AICS is a more useful method for evaluating the probability of cancer incidence than for predicting onset, suggesting that annual AICS should be recommended to detect any malignancy.

Diagnostic yield of the plasma free amino acid index for pancreatic cancer in patients with diabetes mellitus.

OBJECTIVES: A multivariate index calculated using plasma free amino acids (PFAA index) was reported as a diagnostic biomarker for pancreatic cancer (PaC). Although diabetes mellitus (DM) is expected to be an early diagnostic indicator of PaC, identifying the high-risk individuals among patients with DM is warranted. We evaluated the diagnostic yield of the PFAA index for PaC in patients with DM. METHODS: We compared the diagnostic yield of the PFAA index between individuals with and those without DM. Cases and controls were recruited prospectively, and controls were matched to cases at a 1:1 ratio for age, sex, and DM status. RESULTS: A total of 180 case-control pairs were included in the analysis. The prevalence of DM was 53.3%. The sensitivity of the PFAA index was 66.7% in cases with DM and 56.0% in those without DM (P = 0.14), and the specificity was 92.7% in controls with DM and 94.0% in those without DM (P = 0.95). CONCLUSIONS: This matched case-control study revealed a comparable diagnostic yield of the PFAA index for PaC in individuals with and those without DM. The PFAA index can be used as a biomarker for further diagnostic imaging in selected patients with DM.

Plasma amino acid profile associated with fatty liver disease and co-occurrence of metabolic risk factors.

Fatty liver disease (FLD) increases the risk of diabetes, cardiovascular disease, and steatohepatitis, which leads to fibrosis, cirrhosis, and hepatocellular carcinoma. Thus, the early detection of FLD is necessary. We aimed to find a quantitative and feasible model for discriminating the FLD, based on plasma free amino acid (PFAA) profiles. We constructed models of the relationship between PFAA levels in 2,000 generally healthy Japanese subjects and the diagnosis of FLD by abdominal ultrasound scan by multiple logistic regression analysis with variable selection. The performance of these models for FLD discrimination was validated using an independent data set of 2,160 subjects. The generated PFAA-based model was able to identify FLD patients. The area under the receiver operating characteristic curve for the model was 0.83, which was higher than those of other existing liver function-associated markers ranging from 0.53 to 0.80. The value of the linear discriminant in the model yielded the adjusted odds ratio (with 95% confidence intervals) for a 1 standard deviation increase of 2.63 (2.14-3.25) in the multiple logistic regression analysis with known liver function-associated covariates. Interestingly, the linear discriminant values were significantly associated with the progression of FLD, and patients with nonalcoholic steatohepatitis also exhibited higher values.

[Reference Intervals of Standard Test Items in Ningen Dock Examination].

OBJECTIVE: Reference intervals (RIs) were derived from records of 1,499,288 individuals who underwent ningen dock examination in 188 institutes which belong to Japan Society of Ningen Dock in 2012. METHODS: Targets were 27 basic laboratory tests, including the body mass index (BMI) and systolic and diastolic blood pressures (SBP, DBP). Individuals fulfilling strict criteria were chosen: SBP < 130, DBP < 85 mmHg, BMI < 25 Kg/m2, non-smoking, ethanol consumption < 20 g/day, under no medication, with no remarkable current/past illness. The latent abnormal values exclusion (LAVE) method was applied to ensure normal results. RLs were derived using a parametric method with modified Box-Cox power transformation. RESULTS: Among all attendees, 23% fulfilled the criteria. Application of the LAVE method further reduced the dataset by 40-50%. RIs without distinction of the sex and age were SBP, DBP, TP, TB, MCV, WBC, and Plt. Sex-specific RIs were BMI, CRE, UA, TG, HDL-C, ALT, GGT, Glu, RBC, Hb, and Ht. Age-specific RIs in either sex were Alb, AST, HbA1c, TC, LDL-C, FW-LDL-C, nonHDL-C, and ALP. An age-specific RI without distinction of the sex was eGFR. Comparison of derived RIs with clinical decision limits (CDLs) revealed that the upper limits of RIs differed from CDLs according to the sex and age. CONCLUSION: Implementation of sex- and age-related RIs derived from individuals with fully normal ningen dock results will enable the appropriate interpretation of test results in health screening, and promote the effective application of CDLs for therapeutic intervention, taking into account the sex, age, and other health attributes.

The role of amino acid profiles in diabetes risk assessment.

PURPOSE OF REVIEW: The concentrations of plasma-free amino acids, such as branched-chain amino acids and aromatic amino acids, are associated with visceral obesity, insulin resistance, and the future development of diabetes and cardiovascular diseases. This review discusses recent progress in the early assessment of the risk of developing diabetes and the reversal of altered plasma-free amino acids through interventions. Additionally, recent developments that have increased the utility of amino acid profiling technology are also described. RECENT FINDINGS: Plasma-free amino acid alterations in the early stage of lifestyle-related diseases are because of obesity and insulin resistance-related inflammation, and these alterations are reversed by appropriate (nutritional, drug, or surgical) interventions that improve insulin sensitivity. For clinical applications, procedures for measuring amino acids are being standardized and automated. SUMMARY: Plasma-free amino acid profiles have potential as biomarkers for both assessing diabetes risk and monitoring the effects of strategies designed to lower that risk. In addition, the methodology for measuring amino acids has been refined, with the goal of routine clinical application.

A Novel Multivariate Index for Pancreatic Cancer Detection Based On the Plasma Free Amino Acid Profile.

BACKGROUND: The incidence of pancreatic cancer (PC) continues to increase in the world, while most patients are diagnosed with advanced stages and survive <12 months. This poor prognosis is attributable to difficulty of early detection. Here we developed and evaluated a multivariate index composed of plasma free amino acids (PFAAs) for early detection of PC. METHODS: We conducted a cross-sectional study in multi-institutions in Japan. Fasting plasma samples from PC patients (n = 360), chronic pancreatitis (CP) patients (n = 28), and healthy control (HC) subjects (n = 8372) without apparent cancers who were undergoing comprehensive medical examinations were collected. Concentrations of 19 PFAAs were measured by liquid chromatography-mass spectrometry. We generated an index consisting of the following six PFAAs: serine, asparagine, isoleucine, alanine, histidine, and tryptophan as variables for discrimination in a training set (120 PC and matching 600 HC) and evaluation in a validation set (240 PC, 28 CP, and 7772 HC). RESULTS: Several amino acid concentrations in plasma were significantly altered in PC. Plasma tryptophan and histidine concentrations in PC were particularly low, while serine was particularly higher than that of HC. The area under curve (AUC) based on receiver operating characteristic (ROC) curve analysis of the resulting index to discriminate PC from HC were 0.89 [95% confidence interval (CI), 0.86-0.93] in the training set. In the validation set, AUCs based on ROC curve analysis of the PFAA index were 0.86 (95% CI, 0.84-0.89) for all PC patients versus HC subjects, 0.81 (95% CI, 0.75-0.86) for PC patients from stage IIA to IIB versus HC subjects, and 0.87 (95% CI, 0.80-0.93) for all PC patients versus CP patients. CONCLUSIONS: These findings suggest that the PFAA profile of PC was significantly different from that of HC. The PFAA index is a promising biomarker for screening and diagnosis of PC.

Plasma Free Amino Acid Profiles Predict Four-Year Risk of Developing Diabetes, Metabolic Syndrome, Dyslipidemia, and Hypertension in Japanese Population.

Plasma free amino acid (PFAA) profile is highlighted in its association with visceral obesity and hyperinsulinemia, and future diabetes. Indeed PFAA profiling potentially can evaluate individuals' future risks of developing lifestyle-related diseases, in addition to diabetes. However, few studies have been performed especially in Asian populations, about the optimal combination of PFAAs for evaluating health risks. We quantified PFAA levels in 3,701 Japanese subjects, and determined visceral fat area (VFA) and two-hour post-challenge insulin (Ins120 min) values in 865 and 1,160 subjects, respectively. Then, models between PFAA levels and the VFA or Ins120 min values were constructed by multiple linear regression analysis with variable selection. Finally, a cohort study of 2,984 subjects to examine capabilities of the obtained models for predicting four-year risk of developing new-onset lifestyle-related diseases was conducted. The correlation coefficients of the obtained PFAA models against VFA or Ins120 min were higher than single PFAA level. Our models work well for future risk prediction. Even after adjusting for commonly accepted multiple risk factors, these models can predict future development of diabetes, metabolic syndrome, and dyslipidemia. PFAA profiles confer independent and differing contributions to increasing the lifestyle-related disease risks in addition to the currently known factors in a general Japanese population.

Derivation of gender and age-specific reference intervals from fully normal Japanese individuals and the implications for health screening.

BACKGROUND: With nationwide standardization of laboratory tests among institutions for health screening in Japan, common reference intervals (RIs) were derived from records of 1,500,000 health check attendees. METHODS: Targets were 20 basic laboratory tests including body mass index (BMI) and systolic and diastolic blood pressures (SBP, DBP). Individuals fulfilling the following strict criteria were chosen: SBP<130, DBP<85mmHg, BMI<25kg/m(2), non-smoking, ethanol consumption<20g/day and under no mediation with no remarkable current/past illnesses. The latent abnormal values exclusion (LAVE) method was applied to ensure fully normal results. RIs were derived by parametric method using modified Box-Cox power transformation. RESULTS: Among all attendees, 23% fulfilled the criteria. Application of the LAVE method further reduced the dataset by 40%-50%. Age-related charts of test results differed greatly between genders in almost all tests. Comparison of derived RIs with clinical decision limits (CDLs) revealed that the upper limits of RIs differed from CDLs according to gender and age. CONCLUSIONS: Implementation of gender and age-specific RIs derived from individuals with fully normal health attributes will (1) enable appropriate interpretation of test results in health screening and (2) promote judicious application of CDLs for therapeutic intervention, taking into account gender, age and other health attributes.

Usefulness of circulating amino acid profile and Fischer ratio to predict severity of pulmonary hypertension.

Plasma amino acid concentrations (aminogram) show distinct patterns under various pathologic conditions. However, the plasma aminogram pattern in patients with pulmonary hypertension (PH) has not been elucidated. We sought to examine whether an aminogram could be predictive of clinical severity in patients with PH. We attained fasting plasma aminograms for 140 patients with PH and then compared the patient plasma amino acid levels with those of age- and gender-matched healthy control subjects. Aminograms revealed that the plasma concentrations of many amino acids were significantly different between patients with PH and healthy control subjects. We focused on the Fischer ratio (branched-chain amino acids/aromatic amino acids) as an integrated parameter. In all enrolled patients, Fischer ratio was negatively correlated with New York Heart Association functional class (ρ = -0.37, p <0.001), plasma B-type natriuretic peptide (ρ = -0.35, p <0.001), and pulmonary vascular resistance (ρ = -0.27, p = 0.002) and positively correlated with venous oxygen saturation (ρ = 0.27, p = 0.002) and 6-minute walk distance (ρ = 0.23, p = 0.016). Time course changes in Fischer ratio and in cardiac output were significantly correlated (ρ = 0.39, p = 0.024). The aminogram is changed in patients with PH, and in these patients, Fischer ratio decreases in proportion to the clinical severity of PH.

Body mass index negatively regulates glycated albumin through insulin secretion in patients with type 2 diabetes mellitus.

BACKGROUND: Glycated albumin (GA) is known to be negatively regulated by body mass index (BMI) in non-diabetic subjects and patients with type 2 diabetes mellitus (T2DM). In non-diabetic subjects, a mechanism has been proposed in which chronic inflammation associated with obesity increases albumin metabolism and negatively regulates GA levels. However, whether this same mechanism exists in T2DM is unclear. We investigated the factor(s) which influence GA levels in T2DM patients. METHODS: This study included 179 T2DM patients from among people undergoing complete medical examinations. Correlations between GA and the following variables were examined among fasting samples for T2DM patients: BMI, C-reactive protein (CRP), homeostasis model assessment for ß-cell function (HOMA-ß) and homeostasis model assessment for insulin resistance (HOMA-R). RESULTS: BMI was significantly positively correlated with CRP, but CRP was not significantly correlated with GA. HOMA-ß was significantly positively correlated with BMI and significantly negatively correlated with GA. Multivariate analysis showed that HOMA-ß was a significant explanatory variable for GA, but not CRP and HOMA-R. CONCLUSIONS: Our findings suggest that insulin secretion plays a greater role than chronic inflammation in the mechanism by which BMI negatively regulates GA in T2DM patients.

Current dietary salt intake of Japanese individuals assessed during health check-up.

Excess salt intake is a risk factor for increased blood pressure (BP) and hypertension. To prevent hypertension, the reduction of salt intake is promoted in many countries. For people with hypertension or cardiovascular disease (CVD), a more severe restriction of salt intake is indispensable. Japanese individuals consume high quantities of salt, and it is thus important to determine the degree to which the salt intake of these individuals has been restricted. Here, we investigated the current level of salt consumption of Japanese individuals using data obtained during annual health check-ups. A total of 10 762 individuals were assessed who underwent annual health check-ups at our institution in 2011. The estimated daily salt intake (EDSI) was calculated using spot urine samples. The average EDSI was 7.83±2.02 g per day. BP increased in proportion to the EDSI, and multivariate logistic regression analysis showed that the EDSI was a significant and independent risk factor for hypertension. The average EDSI of the subjects with hypertension or a history of CVD was higher than that of the subjects without these diseases. The subjects who drank more heavily showed higher EDSIs. This study demonstrated that the average EDSI of the subjects needing to restrict their salt intake because of past or present illnesses was high. To achieve adherence to the recommended reduction of salt intake, more efforts are required.

Relationship between serum uric acid and serum oxidative stress markers in the Japanese general population.

BACKGROUND: Increased production of reactive oxygen species is a condition that is associated with, and plays a role in the progression of, various disorders such as hypertension, atherosclerosis, and diabetes. PURPOSE: To assess in vivo oxidative stress levels and antioxidant potential and to analyze the relationship with serum uric acid (UA) levels. METHODS AND RESULTS: Oxidative stress levels (derivatives of reactive oxygen metabolites, d-ROMs) and antioxidant potential (biological antioxidant potential, BAP) were measured in individuals who underwent a general health screening test, and data were analyzed from 8,025 individuals (2,953 women and 5,072 men) who were free from UA-lowering medication. Higher serum UA levels were associated with increased levels of d-ROMs in both genders, and this trend was more prominent in women. In addition, higher UA levels were also associated with higher BAP in both genders, although the dose dependence was not apparent in men. These associations remained statistically significant after adjusting for age, blood pressure, renal function, albuminuria, C-reactive protein, and insulin resistance index. CONCLUSIONS: In individuals who underwent general health screening, serum UA levels were positively associated with both d-ROMs and BAP levels. Whether lowering of UA by lifestyle modification or by medication alters d-ROM/BAP levels awaits further investigations. .

Status of diabetes treatment in Japanese adults: an analysis of the 2009 Japan Society of Ningen Dock database.

OBJECTIVE: The Japan Diabetes Society (JDS) has recommended target levels of glycemic control based on guidelines for the management of diabetes mellitus (DM). The Japan Society of Ningen Dock created a database of subjects receiving annual health examinations nationwide. Using this database, we evaluated the efficacy of current treatment for patients with DM based on the JDS recommendations. METHODS: This multicenter, retrospective study was conducted using data obtained from 21 institutions across Japan. In order to assess the level of glycemic control in the Japanese population, we analyzed previously obtained measurements of HbA1c in 7,180 patients 20 to 79 years of age (mean age: 57.9 ± 8.7 years, 6,007 men and 1,173 women) taking DM medications. RESULTS: According to the JDS guidelines, 44.7% of the patients fell into the good glycemic control group, with an HbA1c level of <7.0% while 22.4% were classified into the poor glycemic control group, with an HbA1c level of ≥ 8.0%. The control of other arteriosclerosis risk factors deteriorated as the glycemic control deteriorated. Lifestyle factors were strongly found to be associated with glycemic control in the patients receiving DM treatment. CONCLUSION: Aggressive lifestyle modification is needed to improve glycemic control in patients with DM.

Relationship between Hb and HbA1c in Japanese adults: an analysis of the 2009 Japan Society of Ningen Dock database.

We investigated the effect of Hb on HbA1c levels in 265,427 Japanese individuals. The divergence between fasting plasma glucose (FPG) and HbA1c levels increased with lower Hb, resulting in HbA1c levels that were higher in relation to than the FPG levels. Similarly, the correlation between FPG and HbA1c levels, stratified by Hb, weakened as Hb decreased.

Lifestyle and glycemic control in Japanese adults receiving diabetes treatment: an analysis of the 2009 Japan Society of Ningen Dock database.

We investigated the level of glycemic control in 7020 patients treated with diabetes medications. We found that the overall mean HbA1c was 7.3% (56 mmol/mol). Over half had HbA1c levels ≥7.0% (53 mmol/mol) and poorer glycemic control was associated with unhealthy lifestyle habits.