| 21. |
- Eriksson, Joel, et al.
(author)
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Causal relationship between obesity and serum testosterone status in men: A bi-directional mendelian randomization analysis
- 2017
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:4
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Journal article (peer-reviewed)abstract
- Context Obesity in men is associated with low serum testosterone and both are associated with several diseases and increased mortality. Examine the direction and causality of the relationship between body mass index (BMI) and serum testosterone. Bi-directional Mendelian randomization (MR) analysis on prospective cohorts. Five cohorts from Denmark, Germany and Sweden (Inter99, SHIP, SHIP Trend, GOOD and MrOS Sweden). 7446 Caucasian men, genotyped for 97 BMI-associated SNPs and three testosterone-associated SNPs. BMI and serum testosterone adjusted for age, smoking, time of blood sampling and site. 1 SD genetically instrumented increase in BMI was associated with a 0.25 SD decrease in serum testosterone (IV ratio: -0.25, 95% CI: -0.42-0.09, p = 2.8*10(-3)). For a body weight reduction altering the BMI from 30 to 25 kg/m(2), the effect would equal a 13% increase in serum testosterone. No association was seen for genetically instrumented testosterone with BMI, a finding that was confirmed using large-scale data from the GIANT consortium (n = 104349). Our results suggest that there is a causal effect of BMI on serum testosterone in men. Population level interventions to reduce BMI are expected to increase serum testosterone in men.
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| 22. |
- Ohlsson, Claes, 1965, et al.
(author)
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Genetic determinants of serum testosterone concentrations in men.
- 2011
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In: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404 .- 1553-7390. ; 7:10
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Journal article (peer-reviewed)abstract
- Testosterone concentrations in men are associated with cardiovascular morbidity, osteoporosis, and mortality and are affected by age, smoking, and obesity. Because of serum testosterone's high heritability, we performed a meta-analysis of genome-wide association data in 8,938 men from seven cohorts and followed up the genome-wide significant findings in one in silico (n=871) and two de novo replication cohorts (n=4,620) to identify genetic loci significantly associated with serum testosterone concentration in men. All these loci were also associated with low serum testosterone concentration defined as <300 ng/dl. Two single-nucleotide polymorphisms at the sex hormone-binding globulin (SHBG) locus (17p13-p12) were identified as independently associated with serum testosterone concentration (rs12150660, p=1.2×10(-41) and rs6258, p=2.3×10(-22)). Subjects with ≥ 3 risk alleles of these variants had 6.5-fold higher risk of having low serum testosterone than subjects with no risk allele. The rs5934505 polymorphism near FAM9B on the X chromosome was also associated with testosterone concentrations (p=5.6×10(-16)). The rs6258 polymorphism in exon 4 of SHBG affected SHBG's affinity for binding testosterone and the measured free testosterone fraction (p<0.01). Genetic variants in the SHBG locus and on the X chromosome are associated with a substantial variation in testosterone concentrations and increased risk of low testosterone. rs6258 is the first reported SHBG polymorphism, which affects testosterone binding to SHBG and the free testosterone fraction and could therefore influence the calculation of free testosterone using law-of-mass-action equation.
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| 23. |
- Zhai, Guangju, et al.
(author)
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Eight common genetic variants associated with serum DHEAS levels suggest a key role in ageing mechanisms.
- 2011
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In: PLoS genetics. - : Public Library of Science (PLoS). - 1553-7404 .- 1553-7390. ; 7:4
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Journal article (peer-reviewed)abstract
- Dehydroepiandrosterone sulphate (DHEAS) is the most abundant circulating steroid secreted by adrenal glands--yet its function is unknown. Its serum concentration declines significantly with increasing age, which has led to speculation that a relative DHEAS deficiency may contribute to the development of common age-related diseases or diminished longevity. We conducted a meta-analysis of genome-wide association data with 14,846 individuals and identified eight independent common SNPs associated with serum DHEAS concentrations. Genes at or near the identified loci include ZKSCAN5 (rs11761528; p = 3.15 × 10(-36)), SULT2A1 (rs2637125; p = 2.61 × 10(-19)), ARPC1A (rs740160; p = 1.56 × 10(-16)), TRIM4 (rs17277546; p = 4.50 × 10(-11)), BMF (rs7181230; p = 5.44 × 10(-11)), HHEX (rs2497306; p = 4.64 × 10(-9)), BCL2L11 (rs6738028; p = 1.72 × 10(-8)), and CYP2C9 (rs2185570; p = 2.29 × 10(-8)). These genes are associated with type 2 diabetes, lymphoma, actin filament assembly, drug and xenobiotic metabolism, and zinc finger proteins. Several SNPs were associated with changes in gene expression levels, and the related genes are connected to biological pathways linking DHEAS with ageing. This study provides much needed insight into the function of DHEAS.
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| 24. |
- Bidlingmaier, Martin, et al.
(author)
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Reference Intervals for Insulin-like Growth Factor-1 (IGF-1) From Birth to Senescence: Results From a Multicenter Study Using a New Automated Chemiluminescence IGF-1 Immunoassay Conforming to Recent International Recommendations.
- 2014
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 99:5
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Journal article (peer-reviewed)abstract
- Context: Measurement of IGF-1 is a cornerstone in diagnosis and monitoring of GH-related diseases, but considerable discrepancies exist between analytical methods. A recent consensus conference defined criteria for validation of IGF-1 assays and for establishment of normative data. Objectives: Our objectives were development and validation of a novel automated IGF-1 immunoassay (iSYS; Immunodiagnostic Systems) according to international guidelines and establishment of method-specific age- and sex-adjusted reference intervals and analysis of their robustness. Setting and Participants: We conducted a multicenter study with samples from 12 cohorts from the United States, Canada, and Europe including 15ü014 subjects (6697 males and 8317 females, 0-94 years of age). Main Outcome Measures: We measured concentrations of IGF-1 as determined by the IDS iSYS IGF-1 assay. Results: A new IGF-1 assay calibrated against the recommended standard (02/254) and insensitive to the 6 high-affinity IGF binding proteins was developed and rigorously validated. Age- and sex-adjusted reference intervals derived from a uniquely large cohort reflect the age-related pattern of IGF-1 secretion: a decline immediately after birth followed by an increase until a pubertal peak (at 15 years of age). Later in life, values decrease continuously. The impact of gender is small, although across the lifespan, women have lower mean IGF-1 concentrations. Geographical region, sampling setting (community or hospital based), and rigor of exclusion criteria in our large cohort did not affect the reference intervals. Conclusions: Using large cohorts of well-characterized subjects from different centers allowed construction of robust reference ranges for a new automated IGF-1 assay. The strict adherence to recent consensus criteria for IGF-1 assays might facilitate clinical application of the results.
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| 25. |
- Friedrich, Nele, et al.
(author)
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Age and sex specific reference intervals across life-span for insulin-like growth factor binding protein 3 (IGFBP-3) and the IGF-I/IGFBP-3 ratio measured by new automated chemiluminescence assays.
- 2014
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 99:5
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Journal article (peer-reviewed)abstract
- Context: Measurement of IGFBP-3 can aid the diagnosis of growth hormone related diseases. Furthermore, epidemiological studies suggest that IGFBP-3 and the molar IGF-I/IGFBP-3 ratio are associated with clinical endpoints like cancer or cardiovascular disease. However, their clinical use is limited by the lack of validated reference intervals. Objectives: Establishment of age- and sex-specific reference intervals for IGFBP-3 and the molar IGF-I/IGFBP-3 ratio by newly developed automated immunoassays. Setting: Multicentre study with samples from 11 cohorts from the USA, Canada and Europe Participants: 14,970 subjects healthy subjects covering all ages from birth to senescence. Main outcome measures: Concentrations of IGFBP-3 and the IGF-I/IGFBP-3 ratio as determined by the IDS iSYS IGF-I and IGFBP-3 assays. Results: Both the concentration of IGFBP-3 and the IGF-I/IGFBP-3 ratio are mainly determined by age. IGFBP-3 concentrations increase until the age of 22 years, with a plateau being visible between 15 and 25 years. Determined by the high peripubertal peak in IGF-I, the peak in the IGF-I/IGFBP-3 ratio occurs already around the age of 15, with a slightly earlier and higher peak in females. Beyond the age of 60, IGFBP-3 concentrations remain higher in females, whereas IGF-I as well as the IGF-I/IGFBP-3 ratio remain significantly higher in males. Conclusions: We present an extensive set of assay specific, age and sex-adjusted normative data for concentrations of IGFBP-3 and the molar IGF-I/IGFBP-3 ratio and demonstrate distinct sex specific differences across lifespan.
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| 26. |
- Robinson-Cohen, Cassianne, et al.
(author)
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Genetic Variants Associated with Circulating Parathyroid Hormone.
- 2017
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In: Journal of the American Society of Nephrology : JASN. - 1533-3450. ; 28:5, s. 1553-1565
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Journal article (peer-reviewed)abstract
- Parathyroid hormone (PTH) is a primary calcium regulatory hormone. Elevated serum PTH concentrations in primary and secondary hyperparathyroidism have been associated with bone disease, hypertension, and in some studies, cardiovascular mortality. Genetic causes of variation in circulating PTH concentrations are incompletely understood. We performed a genome-wide association study of serum PTH concentrations among 29,155 participants of European ancestry from 13 cohort studies (n=22,653 and n=6502 in discovery and replication analyses, respectively). We evaluated the association of single nucleotide polymorphisms (SNPs) with natural log-transformed PTH concentration adjusted for age, sex, season, study site, and principal components of ancestry. We discovered associations of SNPs from five independent regions with serum PTH concentration, including the strongest association with rs6127099 upstream of CYP24A1 (P=4.2 × 10(-53)), a gene that encodes the primary catabolic enzyme for 1,25-dihydroxyvitamin D and 25-dihydroxyvitamin D. Each additional copy of the minor allele at this SNP associated with 7% higher serum PTH concentration. The other SNPs associated with serum PTH concentration included rs4074995 within RGS14 (P=6.6 × 10(-17)), rs219779 adjacent to CLDN14 (P=3.5 × 10(-16)), rs4443100 near RTDR1 (P=8.7 × 10(-9)), and rs73186030 near CASR (P=4.8 × 10(-8)). Of these five SNPs, rs6127099, rs4074995, and rs219779 replicated. Thus, common genetic variants located near genes involved in vitamin D metabolism and calcium and renal phosphate transport associated with differences in circulating PTH concentrations. Future studies could identify the causal variants at these loci, and the clinical and functional relevance of these variants should be pursued.
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