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Background and aims: Glycated hemoglobin A1c (HbA1c) ≥6.5% (or 48mmol/mol) has been recommended as a new diagnostic criterion for diabetes; however, limited literature is available regarding the effect of age on the HbA1c for diagnosing diabetes and the causes for this age effect remain unknown. In this study, we investigated whether and why age affects the diagnostic efficiency of HbA1c for diabetes in a community-based Chinese population. Methods: In total, 4325 participants without previously known diabetes were enrolled in this study. Participants were stratified by age. Receiver operating characteristic curve (ROC) was plotted for each age group and the area under the curve (AUC) represented the diagnostic efficiency of HbA1c for diabetes defined by the plasma glucose criteria. The area under the ROC curve in each one-year age group was defined as AUCage. Multiple regression analyses were performed to identify factors inducing the association between age and AUCage based on the changes in the β and P values of age. Results: The current threshold of HbA1c (≥6.5% or 48mmol/mol) showed low sensitivity (35.6%) and high specificity (98.9%) in diagnosing diabetes. ROC curve analyses showed that the diagnostic efficiency of HbA1c in the ≥75 years age group was significantly lower than that in the 45–54 years age group (AUC: 0.755 vs. 0.878; P<0.001). Pearson correlation analysis showed that the AUCage of HbA1c was negatively correlated with age (r = -0.557, P = 0.001). When adjusting the red blood cell (RBC) count in the multiple regression model, the negative association between age and AUCage disappeared, with the regression coefficient of age reversed to 0.001 and the P value increased to 0.856. Conclusions: The diagnostic efficiency of HbA1c for diabetes decreased with aging, and this age effect was induced by the decreasing RBC count with age. HbA1c is unsuitable for diagnosing diabetes in elderly individuals because of their physiologically decreased RBC count. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to investigate the association of serum betatrophin with the status and progression of nonalcoholic fatty liver disease (NAFLD). Methods: A total of 249 subjects who received ultrasonic examination of liver fat content (LFC) were recruited. Anthropometric and biochemical examinations were performed. Serum betatrophin was measured by ELISA. Results: Compared with control group, serum betatrophin significantly increased in NAFLD group (P < 0.05). There was significant difference in serum betatrophin among control, low liver fat content (LLFC), and high liver fat content (HLFC) groups (P < 0.01). After adjustment for gender, age, BMI, FPG and HbA1c, the betatrophin positively correlated with LFC (r = 0.185, P < 0.01) and TG (r = 0.195, P < 0.01). Stepwise multiple regression analysis indicated serum betatrophin was independently related to LFC (P < 0.05). Multivariate logistic regression analysis revealed subjects in the highest tertile of serum betatrophin had higher odds of having NAFLD after adjustment for traditional NAFLD risk factors (OR = 2.88, 95%CI: 1.15–7.19) (P<0.05). Conclusion: Serum betatrophin is an independent risk factor for NAFLD and potential non-invasive marker for its progression. Serum betatrophin may be helpful for the early diagnosis of NAFLD and improvement of its prognosis. [ABSTRACT FROM AUTHOR]

Background/Objectives: Vitamin D exerts metabolic activities. We investigated whether the 25-hydroxy vitamin D [25(OH)D] is associated with liver fat content (LFC) and non-alcoholic fatty liver disease (NAFLD) in a middle-aged, elderly Chinese population. Subject/Methods: A total of 2,960 participants (954 men and 2,006 women) aged over 45 years old were enrolled. Each participant underwent a standard interview, anthropometric measurements and laboratory examinations. Vitamin D deficiency and insufficiency was diagnosed when serum 25(OH) D level was < 50 and 50–75nmol/L. An ultrasound quantitative method was used to assess the LFC. Results: Among the 2,960 participants, 1,982 (67.0%) subjects had vitamin D deficiency, 769 (26.0%) had vitamin D insufficiency, and 209 (7%) had normal vitamin D. Male subjects with vitamin D deficiency and insufficiency had significantly higher LFC than those with normal 25(OH)D (P = 0.034), while the LFC values showed no significant difference among the female subjects with vitamin D sufficiency, insufficiency and deficiency (P = 0.396). Univariate correlation analysis showed that 25(OH)D had a significantly negative association with LFC in men (r = -0.085, P = 0.009), but not in women. After adjusting for age, cigarette smoking, examination season, serum calcium, PTH and all possible confounders that displayed significant associations with LFC in univariate correlation analysis, serum 25(OH)D remained associated with LFC in middle-aged and elderly Chinese men. Conclusion: Serum 25(OH)D level was inversely associated with LFC in middle-aged and elderly Chinese men. [ABSTRACT FROM AUTHOR]