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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.

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.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.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.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.

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.

Context: The risk of many conditions, including prostate cancer, breast cancer, and osteoporosis, is associated with serum levels of sex steroids. Objective: The aim of the study was to identify genetic variations in sex steroid-related genes that are associated with serum levels of estradiol (E2) and/or testosterone in men. Design: Genotyping of 604 single nucleotide polymorphisms in 50 sex steroid-related candidate genes was performed in the Gothenburg Osteoporosis and Obesity Determinants (GOOD) study (n = 1041 men; age, 18.9 ± 0.6 yr). Replications of significant associations were performed in the Osteoporotic Fractures in Men (MrOS) Sweden study (n = 2568 men; age, 75.5 ± 3.2 yr) and in the MrOS US study (n = 1922 men; age, 73.5 ± 5.8 yr). Serum E2, testosterone, and estrone (E1) levels were analyzed using gas chromatography/mass spectrometry. Results: The screening in the GOOD cohort identified the single nucleotide polymorphism rs2470152 in intron 1 of the CYP19 gene, which codes for aromatase, responsible for the final step of the biosynthesis of E2 and E1, to be most significantly associated with serum E2 levels (P = 2 × 10−6). This association was confirmed both in the MrOS Sweden study (P = 9 × 10−7) and in the MrOS US study (P = 1 × 10−4). When analyzed in all subjects (n = 5531), rs2470152 was clearly associated with both E2 (P = 2 × 10−14) and E1 (P = 8 × 10−19) levels. In addition, this polymorphism was modestly associated with lumbar spine BMD (P < 0.01) and prevalent self-reported fractures (P < 0.05). Conclusions: rs2470152 of the CYP19 gene is clearly associated with serum E2 and E1 levels in men.

Primary hyperparathyroidism (PHPT) and associated morbidity are comprehensively assessed in elderly females; however, less is known of the disease in younger women.Our objectives were to estimate the prevalence of mild disturbances in calcium homeostasis, which could be analogous with early PHPT, in a premenopausal population, and determine the potential presence of associated morbidity.Initial results from this longitudinal study are from 2002-2004.We conducted a population-based screening of serum (s)-calcium in conjunction with routine mammography.Participants included premenopausal women, 40-50 yr of age (n = 1900). Cases fulfilling previously evaluated biochemical criteria for PHPT (n=214) were matched to controls (n = 214).All participants underwent investigation, including screening of parameters of calcium homeostasis, dual x-ray absorptiometry, and body mass index assessment, and filled out extensive health and quality of life (SF-36) questionnaires. Participants were divided into four groups depending on the relation between s-calcium/intact PTH. Statistical comparisons between cases and controls as well as among the four groups were performed to evaluate morbidity.The prevalence of assumed mild PHPT, i.e. inappropriate intact PTH value in relation to total s-calcium, was estimated to be 5.1% (n = 96). Women with mild disturbances in calcium homeostasis had statistically significant lower bone mineral density in the proximal femur and femoral neck, higher body mass index, and lower scores for vitality and general health in the analysis of SF-36.Mild disturbances in calcium homeostasis in premenopausal women were more prevalent than previously thought and were associated with obesity, lower bone mineral density, and decreased quality of life.

Context: Previous in vitro studies have demonstrated that the UDP glucuronosyltransferase (UGT)2B15 and UGT2B17 glucuronidate androgens and their metabolites. Objective: Our objective was to determine in vivo whether the UGT2B15 D85Y and the UGT2B17 deletion polymorphisms predict androgen glucuronidation and body composition. Participants: Two population-based cohorts including young adult (n = 1068; age = 18.9 yr) and elderly (n = 1001; age = 75.3 yr) men were included in the study. Main Outcome Measures: Serum and urine levels of testosterone (T) and dihydrotestosterone (DHT) were measured by gas chromatography-mass spectrometry, and serum levels of the major glucuronidated androgen metabolites androstane-3α,17β-diol(androstanediol)-3-glucuronide, androstanediol-17-glucuronide, and androsterone-glucuronide were measured by liquid chromatography-tandem mass spectrometry. Body composition was measured by dual-energy x-ray absorptiometry. Results: Both the UGT2B15 D85Y and the UGT2B17 deletion polymorphisms were associated with serum levels of androstanediol-17-glucuronide (P < 0.001) but not with levels of androstanediol-3-glucuronide or androsterone-glucuronide in both cohorts. Glucuronidation of T and DHT was associated with the UGT2B17 deletion but not with the UGT2B15 D85Y polymorphism, suggested by strong associations between the deletion polymorphism and urine levels of these two hormones. Both polymorphisms were associated with several different measures of fat mass (P < 0.01). The UGT2B17 deletion polymorphism was associated with insulin sensitivity (P < 0.05) as indicated by the homeostasis model assessment index. Conclusions: The UGT2B15 D85Y and the UGT2B17 deletion polymorphisms are both predictors of the glucuronidation pattern of androgens/androgen metabolites. Our findings indicate that UGT2B17 is involved in 17-glucuronidation of mainly T but also of DHT and androstanediol and that UGT2B15 is involved in the 17-glucuronidation of androstanediol. Furthermore, these two polymorphisms are predictors of fat mass 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-3α,17β-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-3α,17β-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.

Context: SHBG regulates free sex steroid levels, which in turn regulate skeletal homeostasis. Twin studies have demonstrated that genetic factors largely account for interindividual variation in SHBG levels. Glucuronidated androgen metabolites have been proposed as markers of androgenic activity. Objective: Our objective was to investigate whether polymorphisms in the SHBG gene promoter [(TAAAA)n microsatellite and rs1799941 single-nucleotide polymorphism] are associated with serum levels of SHBG, sex steroids, or bone mineral density (BMD) in men. Design and Study Subjects: We conducted a population-based study of two cohorts of Swedish men: elderly men (MrOS Sweden; n ≅ 3000; average age, 75.4 yr) and young adult men (GOOD study; n = 1068; average age, 18.9 yr). Main Outcome Measures: We measured serum levels of SHBG, testosterone, estradiol, dihydrotestosterone, 5α-androstane-3α,17β-diol glucuronides, androsterone glucuronide, and BMD determined by dual-energy x-ray absorptiometry. Results: In both cohorts, (TAAAA)n and rs1799941 genotypes were associated with serum levels of SHBG (P < 0.001), dihydrotestosterone (P < 0.05), and 5α-androstane-3α,17β-diol glucuronides (P < 0.05). In the elderly men, they were also associated with testosterone and BMD at all hip bone sites. The genotype associated with high levels of SHBG was also associated with high BMD. Interestingly, male mice overexpressing human SHBG had increased cortical bone mineral content in the femur, suggesting that elevated SHBG levels may cause increased bone mass. Conclusions: Our findings demonstrate that polymorphisms in the SHBG promoter predict serum levels of SHBG, androgens, and glucuronidated androgen metabolites, and hip BMD in men.

The gene mutated in autosomal dominant hypophosphatemic rickets (ADHR), a phosphate wasting disorder, has been identified as FGF-23, a protein that shares sequence homology with fibroblast growth factors (FGFs). Patients with ADHR display many of the clinical and laboratory characteristics that are observed in patients with oncogenic hypophosphatemic osteomalacia (OHO), a disorder thought to arise by the secretion of a phosphate wasting factor from different mesenchymal tumors. In the present studies, we therefore investigated whether FGF-23 is a secreted factor and whether it is abundantly expressed in OHO tumors. After transient transfection of OK-E, COS-7, and HEK293 cells with the plasmid encoding full-length FGF-23, all three cell lines efficiently secreted two protein species into the medium that were approximately 32 and 12 kDa upon SDS-PAGE and subsequent Western blot analysis using an affinity-purified polyclonal antibody to FGF-23. Furthermore, Northern blot analysis using total RNA from five different OHO tumors revealed extremely high levels of FGF-23 mRNA, and Western blot analysis of extracts from a sixth tumor detected the 32 kDa FGF-23 protein species. In summary, FGF-23, the gene mutated in ADHR, is a secreted protein and its mRNA is abundantly expressed by several different OHO tumors. Our findings indicate that FGF-23 may be a candidate phosphate wasting factor, previously designated "phosphatonin".

Interleukin-13 (IL-13) is a recently identified cytokine that is secreted by activated T cells and regulates inflammatory responses. We have investigated the effects of IL-13 on isolated human osteoblast-like cells (hOB). IL-13 dose-dependently (1-100 pmol/L) reduced the incorporation rate of [3H]thymidine in hOB cells by more than 50%. Using a cell metabolic assay as well as direct cell counting, we found that treatment with IL-13 lead to a decrease in hOB cell number. The effect was both time and dose dependent, and after 12 days of culture, treatment with IL-13 (0.1 nmol/L) caused a 70% decrease in the number of cells. Also, IL-13 increased the levels of IL-6 messenger ribonucleic acid in hOBs, as measured by ribonuclease protection assay, and stimulated secretion of IL-6 into culture supernatants. In conclusion, IL-13 inhibits cell proliferation and increases IL-6 formation in human osteoblasts. Our findings suggest that IL-13 may cause bone loss due to impaired osteoblastic growth and IL-6-induced osteoclast recruitment.

Idiopathic osteoporosis in younger individuals could be related to reduced bone formation rather than increased bone resorption, and disturbances in GH or insulin-like growth factor (IGF)-I production could be involved in its pathogenesis. In the present study, men with idiopathic osteoporosis were compared with healthy men, with respect to bone histomorphometry and to serum levels of IGF-I, IGF-II, IGF binding protein (IGFBP)-2 and IGFBP-3, and 24-h urinary excretion of GH. Mean wall thickness was reduced in the patients (48.3 ± 7.2 vs. 61.7 ± 5.4 μm, P < 0.001). Also, resorption depth was decreased, albeit to a lesser degree (54.4 ± 3.8 vs. 60.7 ± 5.3 μm, P < 0.01), thus creating a pronounced negative balance (−6.04 ± 9.8 vs. 0.96 ± 3.2 μm, P < 0.05). In the patients, serum concentrations of IGFBP-3 were reduced, compared with controls, with a 46% lower mean value; whereas levels of IGF-I, IGF-II, IGFBP-2, and GH were similar in the two groups. Thus, there was a significant negative balance caused by a ...