Xuefeng Yu

Increasing trends in central obesity among Chinese adults with normal body mass index, 1993–2009

BackgroundCentral obesity is thought to be more pathogenic than overall obesity and studies have shown that the association between waist circumference (WC) and mortality was strongest in those with a normal body mass index (BMI). The objective of our study was to determine secular trends in the prevalence of central obesity (WC ≥ 90 cm for men and ≥ 80 cm for women) among Chinese adults with normal BMI from 1993 to 2009 and to examine the impact of performance of combined BMI and WC on the prevalence of obesity in Chinese adults.MethodsWe used data from the China Health and Nutrition Survey (CHNS) conducted from 1993 to 2009. From which we included a total of 52023 participants aged ≥ 18 years.ResultsThe age-standardized prevalence of central obesity among Chinese adults with BMI < 25 kg/m2 increased from 11.9% in 1993 to 21.1% in 2009 (P for linear trend <0.001). The upward trends were noted in both genders, all ages, rural/urban settings, and education groups (all P for linear trend <0.001), with greater increments in men, participants aged 18–64 years, and rural residents (P for interaction terms survey × sex, survey × age, and survey × rural/urban settings were 0.042, 0.003, and < 0.001, respectively). Trends in the prevalence of central obesity were similar when a more stringent BMI < 23 kg/m2 cut point (Asian cut point) was applied. Central obesity is associated with a higher risk of incident hypertension within normal BMI category. More than 65% individuals with obesity would be missed if solely BMI was measured.ConclusionsWe observed an upward trend in the prevalence of central obesity among participants with normal BMI irrespective of sex, age, rural/urban settings, and education level. Central obesity is associated with a higher risk of incident hypertension within normal BMI category. Approximately two thirds of the individuals with obesity would be missed if WC was not measured. It is, therefore, urgent to emphasize the importance of WC as a measure to monitor the prevalence of obesity.

Th17 cells in type 1 diabetes

T1D is an autoimmune disorder, which involves the CD4(+) as well as CD8(+) T-cell-mediated destruction of β cells. Recently, another population of T cells (Th17) is found to be involved in T1D pathology. This review will discuss the characteristics of Th17 cells and the mechanism of Th17-mediated T1D development. Th17 cell expansion is unstrained under T1D condition. Certain Treg cells are defective in T1D and lose the control of Th17 expansion. In addition, the altered function of APCs and a subset of monocytes which spontaneously secrete IL-1β and IL-6 in T1D determine the abnormal expansion of Th17 as well. The pathogenic Th17 cells can cause the imbalance between Teff and Treg cells. Conversion from Th17 to Th1 phenotype and Th17 stimulated CTL responses may play an accessory role in T1D as well. Due to the effects of Th17 on T1D, therapeutic strategies designed to inhibit these cells are applicable and the positive effects are obvious. Taken together, Th17 may exert essential effects on the development of T1D. Identification of the underlying mechanism may inspire new viewpoints for the therapy of this disease.

Association between oxidative stress and telomere length in Type 1 and Type 2 diabetic patients

Background: Increasing evidence showed that telomere length was shorter in age-related diseases, but the mechanism of this phenomenon is still unclear. Aim: To determine whether telomere shortening occurs in Type 1 diabetes (T1D) and Type 2 diabetes (T2D), and explore the effect of antioxidant status on the telomere length. Subjects and methods: T2D patients (no.=62), T1D patients (no.=34), and non-diabetic subjects used as control (CTL) (no.=40) were included in this study. Leukocyte telomere length ratio (T/S ratio) was measured using a quantitative PCR and analyzed. Antioxidant status was estimated by human 8-hydroxy-desoxyguanosine quantization. Other biomarkers, such as fasting plasma glucose, fasting insulin, glycated hemoglobin (HbA1c) and lipid profile were also measured. Results: Compared with CTL group [T/S ratio (mean±SD), 2.39±0.55], leukocyte telomere length was significantly shorter in T2D group (1.67±0.50) and T1D group (1.77±0.50). 8-OHdG that indicated oxidative stress was significantly higher in T2D (2.99±0.85 ng/ml) and T1D (2.03±0.92 ng/ml) group than in CTL group (0.90±0.46 ng/ml). T/S ratio was significantly negatively correlated with age, waist circumference, waist-to-hip ratio, diastolic blood pressure, fasting plasma glucose, HbA1c, homeostasis model assessment of insulin resistance and 8-OHdG in the whole population. 8-OHdG was independent risk factor for telomere shortening in both T1D (p=0.018) and T2D group (p=0.022). Conclusions: In our study, shorter telomere length and increased oxidative stress were observed in both T1D and T2D. Older people with central obesity, hyperglycemia, insulin resistance and severe antioxidant status tended to have shorter telomere length. In addition, 8-OHdG was an independent predictor for telomere length for both T1D and T2D patients.

Nontraditional risk factors for cardiovascular disease and visceral adiposity index among different body size phenotypes

BACKGROUND AND AIMSnIncreased cardiovascular disease and mortality risk in metabolically healthy obese (MHO) individuals remain highly controversial. Several studies suggested risk while others do not. The traditional cardiovascular risk factors may be insufficient to demonstrate the complete range of metabolic abnormalities in MHO individuals. Hence, we aimed to compare the prevalence of elevated lipoprotein (a), apolipoprotein B, and uric acid (UA) levels, apolipoprotein B/apolipoprotein A1 ratio, and visceral adiposity index (VAI) scores, and low apolipoprotein A1 levels among 6 body size phenotypes (normal weight with and without metabolic abnormalities, overweight with and without metabolic abnormalities, and obese with or without metabolic abnormalities).nnnMETHODS AND RESULTSnWe conducted a cross-sectional analysis of 7765 Chinese adults using data from the nationwide China Health and Nutrition Survey 2009. MHO persons had intermediate prevalence of elevated apolipoprotein B and UA levels, apolipoprotein B/apolipoprotein A1 ratio and VAI scores, and low apolipoprotein A1 levels between metabolically healthy normal-weight (MHNW) and metabolically abnormal obese individuals (Pxa0<xa00.001 for all comparisons). Elevated apolipoprotein B and UA concentrations, apolipoprotein B/apolipoprotein A1 ratio, and VAI scores were all strongly associated with the MHO phenotype (all Pxa0<xa00.01).nnnCONCLUSIONSnPrevalence of elevated apolipoprotein B and UA levels, apolipoprotein B/apolipoprotein A1 ratio and VAI scores, and low levels of apolipoprotein A1 was higher among MHO persons than among MHNW individuals. The elevated levels of the nontraditional risk factors and VAI scores in MHO persons could contribute to the increased cardiovascular disease risk observed in long-term studies.

A meta-analysis of salicylates for type 2 diabetes mellitus

SummaryThe aim of this study was to assess the effects and safety of salicylates on type 2 diabetes mellitus (T2DM). We searched six databases (Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CBM, CNKI and VIP) for all randomized controlled trials (RCTs) and self-control studies which investigated the effects of salicylates on T2DM. We included 34 RCTs and 17 self-control studies involving 13 464 patients with T2DM. It was demonstrated that salicylates had obvious effects on several parameters for patients with T2DM. (1) Any dose of salicylates could significantly reduce HbA1c level [mean difference (MD) −0.39%; 95% CI −0.47 to −0.32] in RCTs, but only high doses of salicylates (≥3000 mg/day) could effectively reduce fasting plasma glucose (FPG) level [standardized mean difference (SMD) −1.05; 95% CI −1.47 to −0.62] for patients with T2DM in both RCTs and self-control studies. Furthermore, high doses of salicylates could also increase plasma fasting insulin level (MD 12.20 mU/L; 95% CI 3.33 to 21.07); (2) In both RCTs and self-control studies, high doses of salicylates could significantly reduce plasma triglycerides concentration. The results for RCTs were MD −0.44 mmol/L, 95% CI −0.71 to −0.18, and those for self-control studies were 227±29 mg/dL (pre-treatment) and 117±8 mg/dL (post-treatment) (P=0.009); (3) All trials which reported cardiovascular events were RCTs using low doses (<1000 mg/day) of salicylates, and it was revealed that aspirin could significantly reduce the risk of myocardial infarction (OR 0.73; 95% CI 0.57 to 0.92); (4) Two RCTs and two self-control studies with ≥3000 mg/day salicylates reported adverse effects, and the overall effects were mild, and tinnitus occurred most frequently. No evidence of gastrointestinal bleeding was found in all these studies. In conclusion, from our systematic review, the anti-diabetic effect of salicylates is in a dose-dependent manner. High doses of salicylates may have beneficial effects on reducing FPG, HbA1c level and increasing fasting insulin concentration, and may also have some positive effects on lipidemia and inflammation-associated parameters for patients with T2DM, without serious adverse effects.The aim of this study was to assess the effects and safety of salicylates on type 2 diabetes mellitus (T2DM). We searched six databases (Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, CBM, CNKI and VIP) for all randomized controlled trials (RCTs) and self-control studies which investigated the effects of salicylates on T2DM. We included 34 RCTs and 17 self-control studies involving 13 464 patients with T2DM. It was demonstrated that salicylates had obvious effects on several parameters for patients with T2DM. (1) Any dose of salicylates could significantly reduce HbA1c level [mean difference (MD) −0.39%; 95% CI −0.47 to −0.32] in RCTs, but only high doses of salicylates (≥3000 mg/day) could effectively reduce fasting plasma glucose (FPG) level [standardized mean difference (SMD) −1.05; 95% CI −1.47 to −0.62] for patients with T2DM in both RCTs and self-control studies. Furthermore, high doses of salicylates could also increase plasma fasting insulin level (MD 12.20 mU/L; 95% CI 3.33 to 21.07); (2) In both RCTs and self-control studies, high doses of salicylates could significantly reduce plasma triglycerides concentration. The results for RCTs were MD −0.44 mmol/L, 95% CI −0.71 to −0.18, and those for self-control studies were 227±29 mg/dL (pre-treatment) and 117±8 mg/dL (post-treatment) (P=0.009); (3) All trials which reported cardiovascular events were RCTs using low doses (<1000 mg/day) of salicylates, and it was revealed that aspirin could significantly reduce the risk of myocardial infarction (OR 0.73; 95% CI 0.57 to 0.92); (4) Two RCTs and two self-control studies with ≥3000 mg/day salicylates reported adverse effects, and the overall effects were mild, and tinnitus occurred most frequently. No evidence of gastrointestinal bleeding was found in all these studies. In conclusion, from our systematic review, the anti-diabetic effect of salicylates is in a dose-dependent manner. High doses of salicylates may have beneficial effects on reducing FPG, HbA1c level and increasing fasting insulin concentration, and may also have some positive effects on lipidemia and inflammation-associated parameters for patients with T2DM, without serious adverse effects.

Association of the ADRA2A polymorphisms with the risk of type 2 diabetes: A meta-analysis

OBJECTIVESnResults from the published studies on the association of ADRA2A (adrenoceptor alpha 2A) variants with type 2 diabetes (T2D) are conflicting and call for further assessment. The aim of this meta-analysis was to quantitatively summarize the effects of the two recently reported ADRA2A single nucleotide polymorphisms (SNPs) rs553668 and rs10885122 on T2D risk.nnnDESIGN AND METHODSnWe searched all the publications about the association between the ADRA2A SNPs and T2D from PubMed and ISI database updated on September 2012. Meta-analysis of the overall odds ratios (ORs) with 95% confidence intervals (CIs) was calculated by using the software STATA 11.0.nnnRESULTSnTwelve studies with 40,828 subjects from seven eligible papers were included in the meta-analysis. Overall, the present meta-analysis failed to support a positive association between ADRA2A SNPs (rs553668 and rs10885122) and susceptibility to T2D (OR=1.05, p=0.17, 95% CI: 0.98, 1.12; and OR=1.06, p=0.11, 95% CI: 0.99, 1.13; respectively). However, in the subgroup analysis by ethnicity, the significant association between rs553668 and the risk of T2D was obtained in Europeans under the recessive genetic model (OR=1.36, p=0.02, 95% CI: 1.05, 1.76).nnnCONCLUSIONSnThis meta-analysis suggested that the AA genotype of rs553668 in ADRA2A might be a genetic risk factor that increases T2D susceptibility in Europeans. However, rs10885122 was unlikely substantially contribute to T2D susceptibility.

Impact of HbA1c criterion on the definition of glycemic component of the metabolic syndrome: the China health and nutrition survey 2009

BackgroundIn 2009, a unified definition of metabolic syndrome (MetS) was proposed, of which, the glycemic component is defined on the basis of fasting plasma glucose (FPG) level. Recently, the American Diabetes Association (ADA) recommended the use of glycated hemoglobin (HbA1c) as an alternative to FPG to define prediabetes. Hence, we aim to compare the performance of HbA1c and FPG in the definition of glycemic component of the MetS among Chinese adults.MethodsWe conducted a cross-sectional analysis of 7641 Chinese participants aged ≥18xa0years using data from the China Health and Nutrition Survey 2009. MetS was defined according to the consensus criteria in 2009. We compared the use of HbA1c versus FPG in the definition of the glycemic component of MetS. Increased HbA1c value was defined following the criterion of HbA1c cut-off point of ≥5.7% recommended by the ADA.ResultsOverall, 1136 (14.9%) had MetS according to FPGu2009≥u20095.6xa0mmol/l, and 1640 (21.5%) had MetS according to HbA1cu2009≥u20095.7%. Compared with individuals with FPG-based diagnosis of MetS, individuals with HbA1c-based diagnosis of MetS were older, had higher levels of LDL-C, magnesium, and transferrin, and lower levels of uric acid. Of those found to have MetS according to either FPG or HbA1c (nu2009=u20092008), overlap between HbA1c- and FPG-based diagnosis of MetS was limited (nu2009=u2009768, 38.2%). The overlap index regarding MetS diagnosed by FPG or HbA1c persisted low in each evaluated subgroup (≤ 50.0%).ConclusionsWe note limited overlap and poor agreement between FPG- and HbA1c-based diagnosis of MetS. Screening MetS through introduction of HbA1c in addition to FPG could contribute to identification of more people with MetS.

Comparison of the performance of HbA1c and fasting plasma glucose in identifying dysglycaemic status in Chinese high-risk subjects.

The aim of the present study was to compare the performance of HbA1c and fasting plasma glucose (FPG) in identifying dysglycaemic status among Chinese participants. Fasting plasma glucose and HbA1c were measured in 2318 subjects with at least one risk factor for diabetes but without being previously diagnosed with diabetes. Using HbA1c to diagnose diabetes resulted in the same classification as FPG for 90.5% of the study participants, with 21.0% (n = 487) classified as having diabetes by both FPG and HbA1c and 69.5% (n = 1610) classified as not having diabetes by both FPG and HbA1c. The kappa (κ) coefficient of the FPG criterion with the HbA1c criterion for diabetes was 0.75 (95% confidence interval (CI) 0.72–0.78). The overlap index regarding diabetes diagnosed by FPG or HbA1c was 68.8%. Of 1610 subjects with FPG < 126 mg/dL and HbA1c < 6.5%, 220 (13.7%) had FPG ≥ 100 mg/dL and HbA1c < 5.7%, whereas 277 (17.2%) had FPG < 100 mg/dL and HbA1c ≥ 5.7%. The κ coefficient of the FPG criterion with the HbA1c criterion for prediabetes was 0.30 (95% CI 0.25–0.35). The overlap index between subjects diagnosed as having prediabetes by FPG of 100–125 mg/dL (impaired fasting glucose (IFG)) or HbA1c of 5.7–6.4% (increased HbA1c (IGH)) was 35.9%. The HbA1c criterion demonstrates reasonable concordance with the FPG criterion for diabetes. Hence, HbA1c and FPG can be used for the diagnosis of diabetes. However, the IGH shows limited overlap with IFG for prediabetes. Introduction of the IGH criterion in addition to IFG for the screening of prediabetes could lead to the identification of more people with this condition.

Sex differences in the impact of nonalcoholic fatty liver disease on cardiovascular risk factors

BACKGROUND AND AIMSnInformation on sex differences in the association of nonalcoholic fatty liver disease (NAFLD) with cardiovascular disease (CVD) risk factors is scarce. We examined whether men exhibit greater differences in established CVD risk factors between NAFLD and non-NAFLD than women.nnnMETHODS AND RESULTSnWe conducted a cross-sectional analysis using a cohort of 10761 apparently healthy Chinese adults who underwent comprehensive health checkups including abdominal ultrasonography. In the setting of NAFLD and non-NAFLD, although men had significantly higher levels of atherogenic lipids as indicated by higher levels of triglyceride, triglyceride/HDL-cholesterol, and lower levels of HDL-cholesterol and worsen renal function as indicated by higher levels of creatinine and lower levels of estimated glomerular filtration rate (eGFR) than female counterparts, men with NAFLD showed greater relative differences in atherogenic lipids and deteriorated renal function than women with NAFLD when compared with their non-NAFLD counterparts. The interactions between sex and NAFLD on triglyceride, HDL-cholesterol, triglyceride/HDL-cholesterol, creatinine, and eGFR were statistically significant (Pxa0<xa00.05). In the multivariate Logistic regression analyses, we observed a stronger association of TG with NAFLD and comparable associations of eGFR or HDL-C with NAFLD in men compared with women.nnnCONCLUSIONnThere was greater adverse influence of NAFLD per se on triglyceride, and triglyceride/HDL-cholesterol in men compared with women. The greater adverse influence of NAFLD per se on HDL-C and eGFR in men compared with women probably related to the gender differences in TG levels.

Secular trends in the prevalence of low risk factor burden for cardiovascular disease according to obesity status among Chinese adults, 1993–2009

BackgroundCardiovascular disease (CVD) and obesity are now common among Chinese. We aimed to examine secular trends in the prevalence of low risk profile and to examine whether comparable changes in the prevalence of low risk profile across waist circumference (WC) groups and body mass index (BMI) categories have occurred.MethodsWe used data from the nationwide China Health and Nutrition Survey conducted in 1993, 1997, 2000, 2004, 2006, and 2009. There were 7274, 8368, 9369, 8948, 8786, and 9278 participants included in the analyses across the six study periods. We created an index of low risk factor burden from the following variables: not currently smoking, BMIu2009<u200925xa0kg/m2, WCu2009<u200990/80xa0cm in men/women, untreated systolic/diastolic blood pressureu2009<u2009120/80xa0mmHg, and not having been previously diagnosed with diabetes.ResultsDuring the period of 1993–2009, the age-adjusted prevalence of low risk profile decreased from 16.2 to 11.5% among men and from 46.3 to 34.6% among women (both Pu2009<u20090.001); Similar significant trends were observed in all age groups, rural/urban settings, education groups, WC status and BMI categories. The change in the prevalence of low risk profile was more striking among obese persons (P for interaction terms cohort *BMI wereu2009<u20090.001). In 2009, 2.0 and 25.6% among central obese men and women had a low risk profile; Of note, was that 0.1 and 0.3% general obese men and women had a low risk profile.ConclusionsThe prevalence of low risk profile declined considerably over the past 17xa0years in all demographic groups, WC status, and BMI categories. Public health prevention strategies are urgently needed.