OBJECTIVE -Accumulating research suggests low-circulating vitamin D concentrations, i.e., 25-hydroxyvitamin-D [25(OH)D], may be associated with an increased prevalence of metabolic syndrome; however, previous studies have not accounted for parathyroid hormone (PTH) levels. We examined the association of 25(OH)D and PTH with the prevalence of metabolic syndrome in a community-based cohort of older adults. RESULTS -In men, there was a significant trend (P ϭ 0.03) of increasing adjusted odds for metabolic syndrome with increasing PTH concentrations, primarily due to an odds ratio of 2.02 (95% CI 0.96 -4.24) in men in the top quintile (Ն63 ng/l) of PTH concentration. This association remained unchanged after taking into account 25(OH)D levels and excluding men with diabetes or impaired renal function; it was attenuated after adjustment for the homeostasis model assessment of insulin resistance. Neither PTH in women nor 25(OH)D levels in either sex was related to the metabolic syndrome. RESEARCH DESIGN AND METHODSCONCLUSIONS -These findings suggest an increased risk of metabolic syndrome with elevated PTH levels in older men and no effect of 25(OH)D concentrations in either sex. The reason for the sex difference in the PTH-metabolic syndrome association is unknown. Prospective studies are necessary to better determine the roles of 25(OH)D and PTH in the etiology of metabolic syndrome. Diabetes Care 30:1549-1555, 2007D ecreased vitamin D and elevated parathyroid hormone (PTH) levels may play a role in the etiology of metabolic syndrome, either through an association with individual components of metabolic syndrome or via insulin resistance (1,2). Vitamin D levels have been shown to be inversely related both with fasting glucose concentrations (3-5) and adiposity (6 -10) and have been suspected to be involved in the regulation of blood pressure, based on blood pressure reduction with vitamin D 3 supplementation in patients with essential hypertension (11,12). Other evidence suggests a role for vitamin D in maintaining normal insulin synthesis and secretion (13,14). Vitamin D and PTH are both responsible for maintaining extracellular calcium homeostasis (19). Vitamin D increases the efficiency of intestinal calcium absorption, and PTH is secreted in response to low-circulating calcium concentrations. Elevated PTH secondary to low vitamin D increases calcium resorption from the skeleton at the expense of an increased risk of fracture (20). Secondary hyperparathyroidism may also increase the risk of developing components of metabolic syndrome, including hypertension (21-26), obesity (6,9,10,27-29), and diabetes (30 -32). However, we are unaware of previous research investigating whether PTH levels are also associated with the metabolic syndrome.Previous studies linking low 25(OH)D with an increased prevalence of metabolic syndrome (1,18) were limited by their inability to simultaneously account for PTH, since both vitamin D and PTH operate within a tightly controlled feedback system to maintain extracellular calcium conce...

OBJECTIVE Evidence on the association of vitamin D with cardiovascular risk factors in youth is very limited. We examined whether low serum vitamin D levels [25(OH)D] are associated with cardiovascular risk factors in US adolescents aged 12–19 years. METHODS Cross-sectional analysis of 3,577 fasting, nonpregnant adolescents without diagnosed diabetes who participated in the 2001–2004 National Health and Nutrition Examination Survey (NHANES). Risk factors for cardiovascular disease measured using standard methods and defined according to age-modified Adult Treatment Panel-III definitions. RESULTS Mean 25(OH)D in US adolescents was 24.8 ng/mL; lowest in black (15.5 ng/mL), intermediate in Mexican American (21.5 ng/mL), and highest in white (28.0 ng/mL) adolescents (p<0.001, for each pair-wise comparison). Low 25(OH)D levels were strongly associated with overweight status and abdominal obesity (ptrend<0.001, for both). Following adjustment for age, sex, race/ethnicity, body mass index, socioeconomic status, and physical activity, 25(OH)D levels were inversely associated with systolic blood pressure (p=0.02) and plasma glucose concentrations (p=0.01). The adjusted odds ratio (95% CI) for those in the lowest (<15 ng/mL) compared to the highest quartile (>26 ng/mL) of 25(OH)D for hypertension was 2.36 (1.33, 4.19); for fasting hyperglycemia 2.54 (1.01, 6.40); for low HDL-cholesterol 1.54 (0.99, 2.39); for hypertriglyceridemia 1.00 (0.49, 2.04); and for metabolic syndrome 3.88 (1.57, 9.58). CONCLUSIONS Low serum vitamin D in US adolescents is strongly associated with an increased prevalence of hypertension, hyperglycemia, and metabolic syndrome, independent of adiposity. Whether the low concentrations of vitamin D among adolescents predicts future adverse health events remains to be determined.

Objective: To test the hypothesis that lower endogenous testosterone levels are associated with higher blood pressure, left ventricular mass, and left ventricular hypertrophy. Design: Population-based cross-sectional study. Methods: Sex hormone levels, measured by immunoassay, anthropometric measurements and resting blood pressure were studied in 1548 men aged 25-84 years; echocardiography was completed in 1264 of these men. Partial correlations and multiple regressions were used to estimate the associations between sex hormones, blood pressure and left ventricular mass by height. Analyses of variance and covariance were used to compare men with categorical hypertension and left ventricular hypertrophy. Results: In age-adjusted partial correlations, total testosterone and sex hormone-binding globulin (SHBG) were each inversely associated with systolic blood pressure (SBP) (P , 0.001). Men with categorical hypertension (SBP $ 140 or diastolic blood pressure (DBP) $ 90 mmHg) had lower levels of total and free testosterone and SHBG before (P , 0.001, P ¼ 0.011 and P , 0.001, respectively) and after (P , 0.001, P ¼ 0.035 and P ¼ 0.002, respectively) adjusting for body mass index (BMI). Total testosterone and SHBG were each inversely associated with left ventricular mass (P , 0.001), and men with left ventricular hypertrophy had significantly lower levels of total testosterone (P ¼ 0.042) and SHBG (P ¼ 0.006); these associations were no longer significant after adjusting for BMI. Conclusion:The results of the present study are consistent with the hypothesis that lower levels of testosterone in men are associated with higher blood pressure, left ventricular mass, and left ventricular hypertrophy. The reduced associations after adjusting for BMI suggest that the association of low testosterone levels with blood pressure and left ventricular mass is mediated by obesity.European Journal of Endocrinology 150 65-71

Associations between the metabolic syndrome and bone health in older men and women: the Rancho Bernardo Study MS may be another risk factor for osteoporotic fractures. The association of MS with higher BMD was explained by the higher BMI in those with MS.

This relation was unchanged after additional adjustment for PTH level (OR, 0.26; 0.15, 0.44; P trend !0.001) and did not differ by sex (P interaction 0.6) or age (! or R50 years; P interaction 0.2). In contrast, the multivariable-adjusted odds for MetSyn increased with increasing PTH among older men (P trend 0.004), but not younger men (P trend 0.4) or women regardless of age (P trend 0.4 in younger and older women). Conclusions: These data suggest an inverse association of 25(OH)D with MetSyn, independent of potential confounding factors, calcium intake, and PTH, and a positive association of PTH with MetSyn among older men.European Journal of Endocrinology 159 41-48

A higher ratio of n-6 to n-3 fatty acids is associated with lower BMD at the hip in both sexes. These findings suggest that the relative amounts of dietary polyunsaturated fatty acids may play a vital role in preserving skeletal integrity in older age.

To examine the relationship of total and free testosterone and sex hormone-binding globulin (SHBG) with central obesity in men, we studied 1548 men aged 25-84 years that took part in the 1994--1995 survey of the Tromsø study. Total testosterone and SHBG were measured by immuno-assay and the free testosterone fraction was calculated. These measurements were analyzed in relation to anthropometric data and lifestyle factors. The age-adjusted correlation between waist circumference (WC) and total testosterone was -0.34 (p < 0.001), between WC and free testosterone -0.09 (p < 0.001) and, between WC and SHBG -0.44 (p < 0.001). Adjusting for BMI and lifestyle factors weakened, but did not eliminate these associations. All hormone and SHBG associations were stronger for WC than for waist-hip ratio or BMI. In age- and BMI-adjusted analyses men with a WC > or = 102 cm had significantly lower levels of total testosterone and SHBG compared to men with an optimal WC, defined as < 94 cm (12.3 vs. 13.9 nmol/l; p < 0.01 and 48.5 vs. 55.1 nmol/l; p < 0.001, respectively). The lowest levels of total and free testosterone were observed in men with relatively high WC despite relatively low overall obesity (BMI), suggesting that WC should be the preferred anthropometric measurement in predicting endogenous testosterone levels.

These results add to the evidence that DHEA/S is a neuroactive steroid and point to the need for careful long-term clinical trials of DHEA therapy in older women with depressed mood.