Background: Previous studies on the effects of lipotoxicity and oxidative stress on islet beta cell function mainly focused on patients with diabetes, whereas studies on normal glucose tolerance (NGT) are few. The aim of this study was to explore the relationships among triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), oxidative stress indicators, insulin resistance, and beta cell function in populations with different glucose and lipid metabolism states. Methods: A total of 517 individuals were recruited from a rural community in Beijing, China. Glucose metabolism status was defined according to the results of a 75-g oral glucose tolerance test (OGTT). Dyslipidemia was defined as abnormal TG, HDL-c, or LDL-c levels. The population was divided into four groups: individuals with normal glucose and lipid levels (group A, n = 62); those with dyslipidemia alone (group B, n = 82); those with dysglycemia alone (group C, n = 121); and those with dysglycemia and dyslipidemia (group D, n = 247). Oxidative stress indicators, including superoxide dismutase (SOD), glutathione reductase (GR) and 8-hydroxydeoxyguanosine (8-OHdG), were measured. Homeostasis model assessment of insulin resistance (HOMA-IR) and glucose disposition index (DI₃₀, DI₁₂₀) were calculated to assess insulin resistance and islet beta cell function, respectively. Stratified multiple linear regression analysis was used to explore relationships between TG, HDL-c, LDL-c, oxidative stress indicators, and insulin resistance (natural log transformation of HOMA-IR, LnHOMA-IR) and beta cell function (natural log transformation of DI₃₀, Ln DI₃₀). Results: Compared with the control group, populations with dyslipidemia and/or dysglycemia showed significantly increased insulin resistance. Dyslipidemia aggravated insulin resistance and beta cell dysfunction in individuals with dysglycemia. Stratified regression analysis showed that TG positively correlated with LnHOMA-IR in individuals with normal glucose levels (beta = 0.321, 0.327, P = 0.011, 0.003 in groups A and B, respectively) and negatively correlated with LnDI₃₀ in participants with dyslipidemia (beta = − 0.225, − 0.122, P = 0.035, 0.048 in groups B and D, respectively). Reduced serum SOD levels in individuals with dysglycemia plus dyslipidemia were observed, and a negative association between TG and SOD levels was found (r = − 0.461, P < 0.001). Conclusion: TG correlated with both insulin resistance and beta cell function in individuals with dyslipidemia alone. SOD negatively correlated with TG, indicating a close relationship between oxidative stress and glucose-lipid metabolism. Due to the adverse effect of hypertriglyceridemia on insulin sensitivity and islet beta cell function, more attention should be paid to the detection and management of hypertriglyceridemia.

Triglyceride/high-density lipoprotein-cholesterol (TG/HDL-C) ratio was a surrogate marker of IR; however, the relationship of TG/HDL-C with IR might vary by ethnicity. This study aims to investigate whether lipid ratios-TG/HDL-C, cholesterol/high-density lipoprotein-cholesterol (TC/HDL-C) ratio, low-density lipoprotein-cholesterol/high-density lipoprotein-cholesterol (LDL-C/HDL-C)) could be potential clinical markers of insulin resistance (IR) and β cell function and further to explore the optimal cut-offs in a Chinese population with different levels of glucose tolerance. Four hundred seventy-nine subjects without a history of diabetes underwent a 75 g 2 h Oral Glucose Tolerance Test (OGTT). New-onset diabetes (n = 101), pre-diabetes (n = 186), and normal glucose tolerance (n = 192) were screened. IR was defined by HOMA-IR > 2.69. Based on indices (HOMA-β, early-phase disposition index [DI30], (ΔIns30/ΔGlu30)/HOMA-IR and total-phase index [DI120]) that indicated different phases of insulin secretion, the subjects were divided into two groups, and the lower group was defined as having inadequate β cell compensation. Logistic regression models and accurate estimates of the areas under receiver operating characteristic curves (AUROC) were obtained. In all of the subjects, TG/HDL, TC/HDL-C, LDL-C/HDL-C, and TG were significantly associated with IR. The AUROCs of TG/HDL-C and TG were 0.71 (95 % CI: 0.66–0.75) and 0.71 (95 % CI: 0.65–0.75), respectively. The optimal cut-offs of TG/HDL-C and TG for IR diagnosis were 1.11 and 1.33 mmol/L, respectively. The AUROCs of TC/HDL-C and LDL-C/HDL-C were 0.66 and 0.65, respectively, but they were not acceptable for IR diagnosis. TG/HDL-C,LDL-C/HDL-C and TG were significantly associated with HOMA-β, but AUROCs were less than 0.50; therefore, the lipid ratios could not be predictors of basal β cell dysfunction. None of the lipid ratios was associated with early-phase insulin secretion. Only TG/HDL-C and TG were significantly correlated with total-phase insulin secretion, but they also were not acceptable predictors of total-phase insulin secretion (0.60 < AUROC < 0.70). In a Chinese population with different levels of glucose tolerance, TG/HDL-C and TG could be the predictors of IR. The lipid ratios could not be reliable makers of β cell function in the population.

Background and aims Aging becomes a growing global concern with an increased risk of neurodegenerative diseases (NDs) that mainly consist of cognitive decline and Parkinson disease (PD). As the most commonly prescribed antidiabetic drug, metformin has been shown to have inconsistent roles in the incidence of NDs. We performed a systematic review and meta-analysis of observational studies to evaluate the effect of metformin exposure on onset of NDs. Methods The observational studies that investigated the associations between metformin and the incidence of NDs were searched in MEDLINE, Embase and Cochrane Library databases. A random-effect model was performed using STATA to calculate the combined ORs. Results In total, 23 comparisons out of 19 studies with 285 966 participants were included. Meta-analysis found there was no significant effect on incidence of all the subtypes of NDs with metformin exposure (OR 1.04, 95% CI 0.92 to 1.17). However, metformin monotherapy was associated with a significantly increased risk of PD incidence compared with non-metformin users or glitazone users (OR 1.66, 95% CI 1.14 to 2.42). Conclusion Metformin has failed to demonstrate a beneficial effect on NDs. In addition, it may increase the risk of PD development. In light of current results, how metformin would impact NDs, especially the potential risk of PD, needs to be scrutinized. The underlying mechanisms are vital to achieve some more profound understanding on the regimen. Trial registration number CRD 42019133285.

Background: To systematically analyze differences in atherosclerotic cardiovascular disease (ASCVD) burden between young and older adults. Methods: We estimated the prevalence, mortality, and disability-adjusted life years (DALYs) of ASCVD, including ischemic heart disease (IHD), ischemic stroke (IS), and peripheral artery disease (PAD), in individuals aged 20–54 and > 55 years from 1990–2019, utilizing data from the 2019 Global Burden of Disease Study. The annual percentage changes (EAPCs) for age-specific prevalence, mortality, or DALY rates were calculated to quantify the temporal trends of ASCVD burden. We also analyzed population attribution fractions (PAF) of premature ASCVD mortality and DALYs for different risk factors and compared the burden of extremely premature, premature, and non-premature ASCVD cases based on clinical classifications. Results: From 1990–2019, the global prevalence rates of IHD, IS, and PAD in the 20–54 years age group increased by 20.55% (from 694.74 to 837.49 per 100,000 population), 11.50% (from 439.48 to 490.03 per 100,000 population), and 7.38% (from 384.24 to 412.59 per 100,000 population), respectively. Conversely, the ASCVD prevalence in > 55years age group decreased. Adverse outcome burdens, including mortality and DALYs, varied among ASCVD subtypes. The decrease in the mortality/DALY burden of IHD and IS was lower in the 20–54 years group than in the > 55 years group. For PAD, DALYs among those aged 20–54 increased but decreased among those aged > 55 years. When grouped according to socio-demographic index (SDI) values, lower SDI regions exhibited a higher proportion of young ASCVD burden. The prevalence of young IHD, IS, and PAD in low SDI regions reached 20.70%, 40.05%, and 19.31% in 2019, respectively, compared with 12.14%, 16.32%, and 9.54%, respectively, in high SDI regions. Metabolic risks were the primary contributors to the ASCVD burden in both age groups. Increased susceptibility to ambient particulate matter pollution and inadequate control of high body-mass index and high fasting plasma glucose in young individuals may partially explain the differing temporal trends between young and older individuals. Conclusions: The ASCVD burden in young individuals may become a growing global health concern, especially in areas with lower socioeconomic development levels that require more effective primary prevention strategies.

Aim: To verify sex differences of GLP‐1RAs for weight reduction.Methods: We searched RCTs reporting weight change by sex from PubMed, Web of Science, Embase, Cochrane Library, and ClinicalTrials registries. Meta‐regression was performed to evaluate the association between weight reduction and sex differences. Subgroup analyses were stratified by individual GLP‐1RA medications, dose, treatment duration, indication, type of control, background treatment, and baseline weight. The study protocol was registered (CRD42023480167).Results: Fourteen studies covering dulaglutide, exenatide, liraglutide, semaglutide, and retatrutide were included in this study. The meta‐analysis showed that females lost more weight than males (MD 1.04 kg [95% CIs 0.70–1.38]; MD 1.69% [95% CI 0.78–2.61]). The pooled results of GLP‐1RAs indicated similar results (MD 0.88 kg [95% CIs 0.67–1.09]). Meta‐regression illustrated that substantial weight reduction was significantly relevant to greater gender differences (β = −0.19 [95% CIs −0.29 to −0.09]). Subgroup analysis demonstrated that indications for weight reduction increased the gender difference in weight reduction (MD 4.21 kg [95% CIs 1.75–6.67]). Background treatment, dose, duration of treatment, baseline weight, and type of control had no subgroup differences in the sex difference in weight reduction of GLP‐1RAs. Dulaglutide (MD 0.88 kg [95% CIs 0.63–1.12]) and semaglutide (MD 1.04 kg [95% CIs 0.45–1.63]) showed statistically significant differences in weight reduction between males and females. No gender difference was observed in the exenatide subgroup analysis.Conclusions: Females lost more weight than males when treated with GLP‐1RAs for weight reduction. The sex difference in weight reduction became more pronounced as the degree of weight reduction increased. Indications for obesity could magnify this sex difference.

To explore influence of carbohydrates/fat proportions, dietary ingredients on telomere length shortening, oxidative stress and inflammation in a Chinese population with different glucose tolerance status. Five hundred and fifty-six Chinese subjects without diabetes history underwent a 75 g, 2 h Oral Glucose Tolerance Test (OGTT). Subjects with diabetes (n = 159), pre-diabetes (n = 197), and normal glucose tolerance (n = 200) were screened. Dietary intakes were evaluated using a semi-quantitative food frequency questionnaire (FFQ). Peripheral blood leukocyte telomere length (LTL) was assessed using a real-time PCR assay. Blood lipid profile, levels of the oxidative stress indicators superoxide dismutase (SOD), glutathione reductase (GR), 8-oxo-2′-deoxyguanosine (8-oxo-dG) and inflammation indicators tumor necrosis factor (TNF-ɑ), interleukine-6 (IL-6) were measured. Levels of HbA1c, plasma glucose, insulin, and C peptide were also determined. Measurements were taken at 0 min, 30 min, 60 min, and 120 min after 75 g OGTT. Insulin sensitivity was evaluated by HOMA-IR. Basal insulin secretion index (HOMA-β), early phase disposition index (DI30) and total phase disposition index (DI120) indicate insulin levels at different phases of insulin secretion. In patients with newly diagnosed diabetes, LTL adjusted by age was longer in HbA1c < 7 % group (log (LTL):1.93 ± 0.25) than in HbA1c ≥ 7 % group (log (LTL):1.82 ± 0.29). LTL was not associated with daily energy intake, diet fat, carbohydrates and protein proportions. Multiple linear regression analysis indicated that legumes, nuts, fish and seaweeds were protective factors for LTL shortening, and sweetened carbonated beverage was a risk factor for LTL shortening ( legumes: β = 0.105, p = 0.018; nuts: β = 0.110, p = 0.011; fish: β = 0.118, p = 0.007; seaweeds: β = 0.116, p = 0.009; sweetened carbonated beverage: β = −0.120, p = 0.004 ). Daily energy intake was positively associated with TNF-ɑ, IL-6 (TNF-ɑ: r = 0.125, p = 0.006;IL-6: r = 0.092, p = 0.04). Fat, carbohydrate proportions were positively associated with TNF-ɑ (fat: r = 0.119, p = 0.008 ; carbohydrate: r = 0.094, p = 0.043). Seaweeds and dairy intake were negatively associated with 8-oxo-dG (seaweed: r = −0.496, p = 0.001;dairy: r = −0.246, p = 0.046 ), vegetables and fruits were positively associated with GR ( vegetables: r = 0.101, p = 0.034;fruits: r = 0.125, p = 0.045). Cereal, meat were positively associated with TNF-ɑ ( cereal: r = 0.091, p = 0.048 ; meat: r = 0.405, p = 0.009). Diabetes patients with better plasma glucose (HbA1c < 7 %) had longer LTL, LTL could reflect plasma glucose status in diabetes patients. LTL were probably not influenced by diet carbohydrates/fat proportions but was associated with diet ingredients. Diet ingredients significantly impacted on markers of inflammation and oxidative stress, which probably had an effect on LTL.