Low Serum Levels of Dehydroepiandrosterone Sulfate Predict All-Cause and Cardiovascular Mortality in Elderly Swedish Men.

Context: The age-related decline in dehydroepiandrosterone (DHEA) levels is thought to be of importance for general and vascular aging. However, data on the association between DHEA and mortality are conflicting. Objectives: We tested the hypothesis that low serum DHEA and DHEA sulfate (DHEA-S) levels predict all-cause and cardiovascular disease (CVD) death in elderly men. Design, Setting, and Participants: We used gas/liquid chromatography-mass spectrometry to analyze baseline levels of DHEA and DHEA-S in the prospective population-based MrOS Sweden study (2644 men, aged 69-81 yr). Mortality data were obtained from central registers and analyzed using Cox proportional hazards regressions. Main Outcome Measures: All-cause and CVD mortality by serum DHEA(-S) levels. Results: During a mean 4.5-yr follow-up, 328 deaths occurred. Low levels of DHEA-S (quartile 1 vs. quartiles 2-4), predicted death from all causes [hazard ratio (HR) 1.54, 95% confidence interval (CI) 1.21-1.96; adjusted for traditional cardiovascular risk factors], from CVD (n = 123 deaths; HR 1.61, 95% CI 1.10-2.37) and ischemic heart disease (n = 73; HR 1.67, 95% CI 1.02-2.74) but not cancer. Analyses with DHEA gave similar results. The association between low DHEA-S and CVD death remained after adjustment for C-reactive protein and circulating estradiol and testosterone levels. When stratified by the median age of 75.4 yr, the mortality prediction by low DHEA-S was more pronounced among younger (age adjusted HR for CVD death 2.64, 95% CI 1.37-5.09) than older men (HR 1.30, 95% CI 0.83-2.04). Conclusions: Low serum levels of DHEA(-S) predict death from all causes, CVD, and ischemic heart disease in older men

Fibroblast growth factor 23, mineral metabolism and mortality among elderly men (Swedish MrOs)

Background: Fibroblast growth factor 23 (FGF23) is the earliest marker of disturbed mineral metabolism as renal function decreases. Its serum levels are associated with mortality in dialysis patients, persons with chronic kidney disease (CKD) and prevalent cardiovascular disease (CVD), and it is associated with atherosclerosis, endothelial dysfunction and left ventricular hypertrophy in the general population. The primary aim of this study is to examine the association between FGF23 and mortality, in relation to renal function in the community. A secondary aim is to examine the association between FGF23 and CVD related death. Methods: The population-based cohort of MrOS Sweden included 3014 men (age 69-81 years). At inclusion intact FGF23, intact parathyroid hormone (PTH), 25 hydroxyl vitamin D (25D), calcium and phosphate were measured. Mortality data were collected after an average of 4.5 years follow-up. 352 deaths occurred, 132 of CVD. Association between FGF23 and mortality was analyzed in quartiles of FGF23. Kaplan-Meier curves and Log-rank test were used to examine time to events. Cox proportional hazards regression was used to examine the association between FGF23, in quartiles and as a continuous variable, with mortality. The associations were also analyzed in the sub-cohort with estimated glomerular filtration rate (eGFR) above 60 ml/min/1.73 m(2). Results: There was no association between FGF23 and all-cause mortality, Hazard ratio (HR) 95% confidence interval (CI): 1.02 (0.89-1.17). For CVD death the HR (95% CI) was 1.26 (0.99 - 1.59)/(1-SD) increase in log(10) FGF23 after adjustment for eGFR, and other confounders. In the sub-cohort with eGFR > 60 ml/min/1.73 m(2) the HR (95% CI) for CVD death was 55% (13-111)/(1-SD) increase in log(10) FGF23. Conclusions: FGF23 is not associated with mortality of all-cause in elderly community living men, but there is a weak association with CVD death, even after adjustment for eGFR and the other confounders. The association with CVD death is noticeable only in the sub-cohort with preserved renal function

Androgen Receptors in Epithelial Cells Regulate Thymopoiesis and Recent Thymic Emigrants in Male Mice

Androgens have profound effects on T cell homeostasis, including regulation of thymic T lymphopoiesis (thymopoiesis) and production of recent thymic emigrants (RTEs), i. e., immature T cells that derive from the thymus and continue their maturation to mature naive T cells in secondary lymphoid organs. Here we investigated the androgen target cell for effects on thymopoiesis and RTEs in spleen and lymph nodes. Male mice with a general androgen receptor knockout (G-ARKO), T cell-specific (T-ARKO), or epithelial cell-specific (E-ARKO) knockout were examined. G-ARKO mice showed increased thymus weight and increased numbers of thymic T cell progenitors. These effects were not T cell-intrinsic, since T-ARKO mice displayed unaltered thymus weight and thymopoiesis. In line with a role for thymic epithelial cells (TECs), E-ARKO mice showed increased thymus weight and numbers of thymic T cell progenitors. Further, E-ARKO mice had more CD4(+)and CD8(+)T cells in spleen and an increased frequency of RTEs among T cells in spleen and lymph nodes. Depletion of the androgen receptor in epithelial cells was also associated with a small shift in the relative number of cortical (reduced) and medullary (increased) TECs and increased CCL25 staining in the thymic medulla, similar to previous observations in castrated mice. In conclusion, we demonstrate that the thymic epithelium is a target compartment for androgen-mediated regulation of thymopoiesis and consequently the generation of RTEs

Leukocyte telomere length is not associated with mortality in older men.

Leukocyte telomere length (LTL) is related to the aging of somatic cells. We hypothesized that LTL is inversely associated with mortality in elderly men. LTL was measured in 2744 elderly men (mean age 75.5, range 69-81years) included in the prospective population-based MrOS-Sweden study. Mortality data were obtained from national health registers with no loss of follow-up. During the follow-up (mean 6.0years), 556 (20%) of the participants died. Using Cox proportional hazards regression, tertile of LTL did not associate with all-cause mortality [tertile 1 (shortest) or 2 (middle) vs. tertile 3 (longest); hazard ratio (HR)=1.05, 95% confidence interval (CI) 0.85-1.28 and HR=0.97, 95% CI 0.79-1.19, respectively]. Furthermore, LTL did not associate with cancer (197 events) or cardiovascular disease (CVD, 206 events) mortality (tertile 1 vs. tertile 3; HR=0.94, 95% CI 0.67-1.34 and HR=0.94, 95% CI 0.68-1.30, respectively). The lack of association between LTL and mortality remained also after adjustment for multiple covariates. Our results demonstrate that LTL is not associated with all-cause mortality or mortality due to cancer or CVD in elderly men. Further studies are needed to determine whether LTL can predict the risk of mortality in elderly women

Low Serum Testosterone and Estradiol Predict Mortality in Elderly Men.

Context: Age-related reduction of serum testosterone may contribute to the signs and symptoms of aging, but previous studies report conflicting evidence about testosterone levels and male mortality. No large prospective cohort study has determined a possible association between serum estradiol and mortality in men. Objective: The main objective was to examine the association between serum testosterone and estradiol and all-cause mortality in elderly men. Design, setting and participants: We used specific gas chromatography-mass spectrometry to analyze serum sex steroids at baseline in older men who participated in the prospective population-based MrOS Sweden cohort (n=3,014, mean 75 years of age, range 69-80). Main outcome measure: All-cause mortality by serum testosterone and estradiol levels. Results: During a mean follow-up period of 4.5 years, 383 deaths occurred. In multivariate hazards regression models, low levels (within quartile 1; versus quartiles 2-4) of both testosterone (hazard ratio [HR] 1.65, 95% confidence interval [CI] 1.29-2.12) and estradiol (HR 1.54, 95% CI 1.22-1.95) associated with mortality. A model including both hormones showed that both low testosterone (HR 1.46, 95% CI 1.11-1.92) and estradiol (HR 1.33, 95% CI 1.02-1.73) predicted mortality. Risk of death nearly doubled (HR 1.96, 95% CI 1.46-2.62) in subjects with low levels of both testosterone and estradiol compared with subjects within quartiles 2-4 of both hormones. Conclusions: Elderly men with low serum testosterone and estradiol have increased risk of mortality, and subjects with low values of both testosterone and estradiol have the highest risk of mortality

Plasma Osteocalcin Is Inversely Related to Fat Mass and Plasma Glucose in Elderly Swedish Men

The osteoblast-derived protein osteocalcin has recently been shown to affect adiposity and glucose homeostasis in mice, suggesting that the skeleton influences energy metabolism through an endocrine mechanism. The aim of this study was to investigate the relationship between plasma osteocalcin and parameters reflecting fat mass and glucose homeostasis in humans. Fasting levels of plasma osteocalcin, plasma glucose, serum insulin, and lipids were analyzed in elderly men (75.3 +/- 3.2 yr of age) in the Gothenburg part (all subjects, n = 1010; nondiabetic, n = 857; diabetic, n = 153) of the MrOS Sweden study. Fat mass and lean mass were analyzed using DXA. Diabetic subjects had lower plasma osteocalcin (-21.7%, p < 0.001) than nondiabetic subjects. For both all subjects and nondiabetic subjects, plasma osteocalcin was clearly inversely related to body mass index (BMI), fat mass, and plasma glucose 3 < 0.001), whereas it was not associated with height or lean mass. Plasma osteocalcin explained a substantial part (6.3%) of the variance in plasma glucose, whereas it associated moderately with serum insulin. multiple linear regression models adjusting for serum insulin and fat mass showed that plasma osteocalcin was an independent negative predictor of plasma glucose (p < 0.001). We herein, for the first time in humans, show that plasma osteocalcin is inversely related to fat mass and plasma glucose. Although one should be cautious with mechanistic interpretations of cross-sectional association studies, our human data support recently published experimental studies, showing endocrine functions of osteoblast-derived osteocalcin on glucose and fat homeostasis

Both Low and High Serum IGF-1 Levels Associate With Increased Risk of Cardiovascular Events in Elderly Men

Context: Most previous prospective studies suggest that low serum IGF-1 associates with increased risk of cardiovascular disease (CVD) events whereas other studies suggest that high serum IGF-1 associates with increased risk of CVD events. Objective: We tested the hypothesis that not only low, but also high serum IGF-1 levels associate with increased risk of CVD events in elderly men. Setting and Design: Serum IGF-1 levels were measured in 2901 elderly men (age 69-81 years) included in the Swedish cohort of the prospective, population-based Osteoporotic Fractures in Men Study (MrOS), Sweden cohort. Data for CVD events were obtained from national Swedish registers with no loss of followup. Results: During followup (median, 5.1 y) 589 participants experienced a CVD event. The association between serum IGF-1 and risk of CVD events was nonlinear, and restricted cubic spline Cox regression analysis revealed a U-shaped association between serum IGF-1 levels and CVD events (P < .01 for nonlinearity). Low as well as high serum IGF-1 (quintile 1 or 5 vs quintiles 2-4) significantly associated with increased risk for CVD events (hazard ratio [HR] = 1.25, 95% confidence interval, [CI], 1.02-1.54; and HR = 1.35, 95% CI 1.10-1.66, respectively). These associations remained after adjustment for prevalent CVD and multiple risk factors. High serum IGF-1 associated with increased risk of coronary heart disease (CHD) events but not with risk of cerebrovascular events. Conclusions: Both low and high serum IGF-1 levels are risk markers for CVD events in elderly men. The association between high serum IGF-1 and CVD events is mainly driven by CHD events

Both Low and High Serum IGF-I Levels Associate with Cancer Mortality in Older Men.

Background: Although recent population-based studies suggest a U-shaped relationship between serum IGF-I concentration and all-cause mortality, the distribution of death causes underlying this association remains unclear. We hypothesized that high IGF-I levels associate with increased cancer mortality, whereas low IGF-I levels associate with increased cardiovascular disease (CVD) mortality. Methods: Serum IGF-I levels were measured in 2901 elderly men (mean age 75.4, range 69-81 yr) included in the prospective population-based Osteoporotic Fractures in Men Study (Sweden) study. Mortality data were obtained from central registers with no loss of follow-up. The statistical analyses included Cox proportional hazards regressions with or without a spline approach. Results: During the follow-up (mean 6.0 yr), 586 of the participants died (cancer deaths, n = 211; CVD deaths, n = 214). As expected, our data revealed a U-shaped association between serum IGF-I levels and all-cause mortality. Low as well as high serum IGF-I (quintile 1 or 5 vs. quintiles 2-4) associated with increased cancer mortality [hazard ratio (HR) = 1.86, 95% confidence interval (CI) = 1.34-2.58; and HR = 1.90, 95% CI = 1.37-2.65, respectively]. Only low serum IGF-I associated with increased CVD mortality (quintile 1 vs. quintiles 2-4, HR = 1.48, 95% CI = 1.08-2.04). These associations remained after adjustment for multiple covariates and exclusion of men who died during the first 2 yr of follow-up.Conclusions:Our findings demonstrate that both low and high serum IGF-I levels are risk markers for increased cancer mortality in older men. Moreover, low IGF-I levels associate with increased CVD mortality

Low serum testosterone and high serum estradiol associate with lower extremity peripheral arterial disease in elderly men - The MrOS study in Sweden

Objectives This study sought to determine whether serum levels of testosterone and estradiol associate with lower extremity peripheral arterial disease (PAD) in a large population-based cohort of elderly men. Background Few studies have explored the relationship between serum sex steroids and lower extremity PAD in men. Methods The Swedish arm of the MrOS (Osteoporotic Fractures in Men) study (n = 3,014; average age 75.4 years) assessed ankle-brachial index (ABI) and defined lower extremity PAD as ABI < 0.90. Radioimmunoassay measured serum levels of total testosterone, estradiol, and sex hormone-binding globulin, and we calculated free testosterone and free estradiol levels from the mass action equations. Results A linear regression model including age, current smoking, previous smoking, diabetes, hypertension, body mass index, free testosterone, and free estradiol showed that free testosterone independently and positively associates with ABI (p < 0.001), whereas free estradiol independently and negatively associates with ABI (p < 0.001). Logistic regression analyses showed that free testosterone in the lowest quartile (vs. quartiles 2 to 4; odds ratio [OR] 1.65, 95% confidence interval [Cl] 1.22 to 2.23, p = 0.001) and free estradiol in the highest quartile (vs. quartiles 1 to 3; OR 1.45, 95% Cl 1.09 to 1.94, p = 0.012) independently associate with lower extremity PAD. Conclusions This cross-sectional study shows for the first time that low serum testosterone and high serum estradiol levels associate with lower extremity PAD in elderly men. Future prospective and interventional studies are needed to establish possible causal relationships between sex steroids and the development of lower extremity PAD in men

Androgens and glucuronidated androgen metabolites are associated with metabolic risk factors in men

Context: Androgens are associated with metabolic risk factors in men. However, the independent impact of androgens and androgen metabolites on metabolic risk factors in men is unclear. Objective: Our objective was to determine the predictive value of serum levels of androgens and glucuronidated androgen metabolites for metabolic risk factors. Design and Study Subjects: We conducted a population-based study of two Swedish cohorts (1068 young adult and 1001 elderly men). Main Outcome Measures: We measured correlation of serum dihydrotestosterone (DHT), testosterone (T), and glucuronidated androgen metabolites with fat mass, fat distribution, serum lipids, and insulin resistance. Results: Both DHT and T were negatively associated with different measures of fat mass in both cohorts (P < 0.001). Further statistical analysis indicated that DHT, but not T, was independently negatively associated with different measures of fat mass and insulin resistance (P < 0.001). The glucuronidated androgen metabolite androstane-3alpha,17beta-diol-17glucuronide (17G) was independently positively associated with fat mass (P < 0.001). Most importantly, the 17G to DHT ratio was strongly correlated, not only with fat mass but also with central fat distribution, intrahepatic fat, disturbed lipid profile, insulin resistance, and diabetes, explaining a substantial part of the total variance in total body fat (12% in young adult men, 15% in elderly men), the homeostasis model assessment index (10%), and high-density lipoprotein cholesterol (7%). Conclusion: Our findings demonstrate that 17-glucuronidation of the DHT metabolite androstane-3alpha,17beta-diol is strongly associated with several metabolic risk factors in men. Future longitudinal studies are required to determine the possible impact of the 17G to DHT ratio as a metabolic risk factor in men