Testosterone, sex hormone-binding globulin and the metabolic syndrome in men: an individual participant data meta-analysis of observational studies.

Low total testosterone (TT) and sex hormone-binding globulin (SHBG) concentrations have been associated with the metabolic syndrome (MetS) in men, but the reported strength of association varies considerably.We aimed to investigate whether associations differ across specific subgroups (according to age and body mass index (BMI)) and individual MetS components.Two previously published meta-analyses including an updated systematic search in PubMed and EMBASE.Cross-sectional or prospective observational studies with data on TT and/or SHBG concentrations in combination with MetS in men.We conducted an individual participant data meta-analysis of 20 observational studies. Mixed effects models were used to assess cross-sectional and prospective associations of TT, SHBG and free testosterone (FT) with MetS and its individual components. Multivariable adjusted odds ratios (ORs) and hazard ratios (HRs) were calculated and effect modification by age and BMI was studied.Men with low concentrations of TT, SHBG or FT were more likely to have prevalent MetS (ORs per quartile decrease were 1.69 (95% CI 1.60-1.77), 1.73 (95% CI 1.62-1.85) and 1.46 (95% CI 1.36-1.57) for TT, SHBG and FT, respectively) and incident MetS (HRs per quartile decrease were 1.25 (95% CI 1.16-1.36), 1.44 (95% 1.30-1.60) and 1.14 (95% 1.01-1.28) for TT, SHBG and FT, respectively). Overall, the magnitude of associations was largest in non-overweight men and varied across individual components: stronger associations were observed with hypertriglyceridemia, abdominal obesity and hyperglycaemia and associations were weakest for hypertension.Associations of testosterone and SHBG with MetS vary according to BMI and individual MetS components. These findings provide further insights into the pathophysiological mechanisms linking low testosterone and SHBG concentrations to cardiometabolic risk

Serum Leptin, Adiponectin and Tumor Necrosis Factor-α in Hyperlipidemic Rats with/without Concomitant Diabetes Mellitus

We compared the lipid profiles and serum levels of leptin, adiponectin and tumor necrosis factor-α (TNF-α) in rats with/without hyperlipidemia and with/without concomitant diabetes mellitus. Forty 10-wk-old male Wistar rats were divided into four groups. Groups A and C received standard food for 12 wks. Groups B and D received a high-fat diet enriched with 2% additional cholesterol. Moreover, insulin-deficient (type I) diabetes mellitus was induced in rats in groups C and D with intraperitoneal injections of streptozotocin. Fasting serum leptin levels were decreased in diabetic groups (groups C and D) compared with controls. Fasting serum adiponectin levels were decreased in groups C and D compared with group A. Serum TNF-α levels were augmented in groups B and D, those fed with an atherogenic diet. By contrast, TNF-α levels were decreased in group C. Our data suggest that serum leptin, adiponectin and TNF-α levels may serve as markers of obesity and type I diabetes mellitus

Relationship of serum Vitamin D concentrations with Adipokines and Cardiometabolic risk among non-Hispanic black type 2 diabetic and non-diabetic subjects: a cross-sectional study

Abstract Background To report the association of serum 25-hydroxyvitamin D [25(OH)D] and its association with adipokines and cardiometabolic risk factors in Haitian Americans (HA) and African Americans (AA) by ethnicity and type 2 diabetes (T2D) status. Methods A cross-sectional study in 197 HA (92 with T2D and 102 without T2D) and 200 AA (97 with T2D and 103 without T2D) recruited in South Florida. Serum 25(OH)D concentrations and adipokines were analyzed by ELISA and cardiometabolic risk factors were indexed by obesity, glycemic control, insulin sensitivity, lipid profile, and blood pressure. Results Controlling for age, BMI, energy intake, smoking status and HOMA2-IR in multivariate linear regression analyses, serum 25(OH)D concentrations were significantly associated with WC (R2 = 0.760, B = − 0.092, P = 0.027), HbA1C (R2 = 0.142, B = − 0.012, P = 0.010), and TG (R2 = 0.159, B = − 1.192, P = 0.003) in only HA without T2D. While serum 25(OH)D concentrations were significantly associated with TC (R2 = 0.168, B = − 0.329, P = 0.040), log leptin (R2 = 0.544, B = − 0.007, P = 0.021), and adiponectin (R2 = 0.144, B = 0.111, P = 0.033), but slightly associated with LDL-c (R2 = 0.133, B = − 0.278, P = 0.064) in only AA without T2D. Among individuals with T2D, serum 25(OH)D concentrations were marginally associated with IL-6 (R2 = 0.109, B = 0.076, P = 0.085) in HA with T2D, and there was a trend toward significance with log leptin (R2 = 0.393, B = − 0.006, P = 0.075) in AA with T2D in regression analysis. Conclusions The findings that the associations of serum 25(OH)D concentrations with adipokines and cardiometabolic factors differ between HA and AA has clinical and public implications to guide design of T2D preventive strategies that are culturally specific even within the same ethnicity