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Objectives: Several studies suggest a link between circulating 25-hydroxyvitamin D (25(OH)D) and metabolic risk factors. However, this relation has been mainly studied in elderly and/or obese subjects. In addition, the relation between 25(OH)D and adiponectin is unclear. The purpose of this study is to look at these relations in non-obese young individuals. Design: We investigated the relation between serum 25(OH)D and adiposity, blood pressure, glucose metabolism, lipid profile, and adiponectin in 381 randomly selected university students (201 males and 180 females, mean age 23.9G3.9). Results: In the overall population, 25(OH)D is significantly inversely correlated with body mass index (BMI), systolic blood pressure (SBP), waist circumference (WC), fasting plasma glucose (FPG), insulin levels, and homeostasis model assessment of insulin resistance (HOMA index) and positively correlated with adiponectin and high density lipoprotein-cholesterol (P!0.01 for all variables). In males, these correlations are still significant for BMI, SBP, WC, and adiponectin (PZ0.02, PZ0.01, PZ0.04 and PZ0.01 respectively); also, 25(OH)D is inversely correlated with low density lipoprotein (LDL)-cholesterol (PZ0.007). In females, 25(OH)D is only inversely correlated with FPG and HOMA index (P!0.001 and PZ0.03 respectively). In multivariate regression analysis models, after adjustment for sex and BMI, 25(OH)D is an independent predictor of FPG and SBP (PZ0.032 and PZ0.05 respectively) in the overall population, while in males 25(OH)D is a predictor of LDL-cholesterol and SBP independently of BMI (PZ0.007 and PZ0.035 respectively). Conclusion: In non-obese young subjects, we observe new relationships between 25(OH)D and several metabolic risk factors and adiponectin. Further research is needed to elucidate the gender differences and to look at the relation between 25(OH)D and adiponectin.European Journal of Endocrinology 160 965-971

Objective: The relationships between adipocytokines, sex steroids and the GH/IGF-I axis is poorly studied and subject to controversy in healthy elderly male subjects. We investigated the association between both adiponectin and leptin, and the metabolic syndrome (MetS), lipid parameters, insulin sensitivity, sex steroids and IGF-I in healthy non-diabetic Lebanese men. Design and methods: In this cross-sectional study, a total of 153 healthy non-diabetic men aged 50 and above (mean age 59.3G7 years) had a detailed clinical and biological evaluation. Subjects were classified according to the National Cholesterol Education Program criteria of the MetS. Insulin sensitivity was determined by the Quantitative Insulin Sensitivity Check Index (QUICKI). Results: Subjects with the MetS had lower adiponectin and higher leptin levels (P!0.0001 for both variables) compared with individuals without the MetS. Adiponectin was significantly correlated with waist size, triglycerides, high-density lipoprotein (HDL) cholesterol and QUICKI (rZK0.33, K0.26, 0.45 and 0.36 respectively, P!0.0001 for all variables). The relation between adiponectin and HDL cholesterol, triglycerides and QUICKI remained significant after adjustment for age and body mass index (BMI). Also, leptin was strongly correlated with waist size and QUICKI (rZ0.63 and K0.63 respectively, P!0.001 for both variables). However, its relation to the lipid profile was weak (for cholesterol rZ0.16, P!0.05; for triglycerides rZ0.17, P!0.05) and disappeared after adjustment for BMI. Adiponectin was positively correlated with sex hormone-binding globulin (SHBG) (rZ0.39, P!0.001) and inversely correlated with free-androgen index (rZK0.24, P!0.01), estradiol and dehydroepiandrosterone sulfate (rZK0.165, P!0.05; rZK0.21, P!0.01 respectively). This difference remained significant for SHBG after adjustment for age and BMI (rZ0.20, P!0.005). Finally, leptin was inversely correlated with total testosterone and SHBG (rZK0.44, P!0.001; rZK0.30, P!0.001 respectively); the relation with testosterone remained significant after adjustment for BMI. No significant relationship of either adiponectin or leptin with GH or IGF-I values was observed. In a stepwise multiple regression analysis, the independent predictors of adiponectin were HDL cholesterol, QUICKI, age and BMI (P!0.0001, PZ0.005, PZ0.002 and PZ0.047 respectively) while for leptin, it was QUICKI, waist size and testosterone (P!0.0001, P!0.0001 and PZ 0.004 respectively). The adjusted R 2 values were 0.34 and 0.55. Conclusion: Our results show that in a healthy elderly male population, both adiponectin and leptin are related to insulin sensitivity, independent of age and BMI. While adiponectin is independently related to triglycerides and HDL cholesterol, the weak relationship of leptin to the lipid profile is completely mediated by BMI. In addition, and more interestingly, both adipocytokines are strongly associated with sex steroids. We speculate that SHBG is regulated by adiponectin and that there is an inhibitory effec...

Our results show that circulating OPG levels are favourably associated with some components of the metabolic syndrome. Also, for the first time, an association between OPG and adiponectin is described. Finally, the negative correlation we found between OPG and free androgen index may suggest a potential role of OPG in the increase in cardiovascular disease related to ageing and sex steroid deficiency.

Objective: We analyzed the relation of osteoprotegerin (OPG) with insulin sensitivity, lipid profile, serum glutamic pyruvic transaminase (SGPT), adipocytokines, and C-reactive protein (CRP) in obese and non-obese subjects. Methods: In the study, 170 subjects (106 obese and 64 non-obese, sex ratio female/maleZ2.03) were included. Thirty-two obese subjects were reevaluated 6 months after the weight loss induced by bariatric surgery. Results: OPG did not differ between obese and non-obese subjects (respective mean values 5.17 and 4.96 pmol/l) or according to gender, but was positively correlated with age (P!0.0001 for both groups). OPG was statistically higher in 18 obese diabetic subjects compared with non-diabetics (PZ0.03). After adjustment for age, no significant correlation was found between OPG and body mass index (BMI), waist, systolic and diastolic blood pressure, cholesterol, triglycerides, high density lipoprotein (HDL) cholesterol, leptin, and adiponectin in both the obese and non-obese subjects. However, OPG was positively correlated with homeostasis model assessment (HOMA) index and SGPT levels in obese subjects at baseline (rZ0.295, rZ0.20, P!0.05) and after adjustment for age (rZ 0.28, rZ0.20, P!0.05). OPG was also significantly correlated with CRP; this correlation persisted after adjustment for age in obese subjects (rZ0.30, P!0.01). In a multivariate analysis in the obese group, HOMA index and CRP were independent predictors of OPG while SGPT was not. Six months post-surgery, OPG did not change, despite a significant reduction in glucose, SGPT, cholesterol, triglycerides, CRP, and leptin values (PZ0.02, PZ0.006, PZ0.007, P!0.001, P!0.001, P!0.001 respectively) and a significant increase in adiponectin and HDL values (P!0.001 for both variables). Conclusion: Our results show that in obese subjects, OPG is not related to BMI. However, we describe new relationships between OPG and both HOMA index and CRP.