Little is known about the relationships of dihydrotestosterone (DHT), a more potent androgen than testosterone (T), with bone mineral density (BMD) and fracture risk. Our objectives were to evaluate ...the relationships of T, DHT and sex hormone binding globulin (SHBG) with BMD, fracture risk, and lean body mass (LBM).
We evaluated 1128 older men free of cardiovascular disease in a prospective cohort study using data from the Cardiovascular Health Study. T and DHT were measured by liquid chromatography–tandem mass spectrometry and SHBG by fluoroimmunoassay. Our outcomes included incident hip fracture (n = 106) over a median of 10.2 years and BMD and LBM by dual-energy x-ray absorptiometry (n = 439).
In Cox regression models mutually adjusted for T, SHBG, and covariates, each standard deviation increment in DHT (0.23 ng/ml) was associated with a 26% lower risk of hip fracture (adjusted hazard ratio aHR 0.74, 95% confidence interval (CI) 0.55–1.00, p = 0.049). Similarly, SHBG was associated with fracture in mutually adjusted models (aHR HR 1.26, 95% CI, 1.01–1.58, p = 0.045). In contrast, T (aHR, 1.16, 95% CI, 0.86–1.56, p = 0.324) was not significantly associated with fracture in mutually adjusted models. T, DHT and SHBG were not associated with BMD. T and DHT were both positively associated with LBM in individual models.
In older men, DHT was inversely associated with hip fracture risk and SHBG was positively associated with hip fracture risk, while T was not. Future studies should elucidate the mechanisms by which DHT affects bone health.
•Dihydrotestosterone (DHT) was associated with lower hip fracture risk in elderly men.•Testosterone (T) was not significantly associated with hip fracture risk.•DHT and T were not significantly related to bone mineral density.•DHT and T were similarly related to greater lean body mass.
Backgrounds and aims: Elevated common carotid artery intima-media thickness (carotid IMT) and diminished flow-mediated dilation (FMD) are early subclinical indicators of atherosclerosis. Serum total ...non-esterified fatty acid (NEFA) concentrations have been positively associated with subclinical atherosclerosis. The relations between individual NEFA, carotid IMT and FMD have as yet to be assessed. Methods: We investigated the associations between fasting serum individual NEFA, carotid IMT and FMD among Cardiovascular Health Study (CHS) participants with (n = 255 for carotid IMT, 301 for FMD) or without (n = 1314 for carotid IMT, 1462 for FMD) known atherosclerotic cardiovascular disease (ASCVD). Using archived samples (fasting) collected from 1996–1997 (baseline), 35 individual NEFAs were measured using gas chromatography. Carotid IMT and estimated plaque thickness (mean of maximum internal carotid IMT) were determined in 1998–1999. FMD was measured in 1997–1998. Linear regression adjusted by the Holm-Bonferroni method was used to assess relations between individual NEFA, carotid IMT and FMD. Results: In multivariable adjusted linear regression models per SD increment, the non-esterified trans fatty acid conjugated linoleic acid (trans-18:2 CLA) was positively associated with carotid IMT β (95% CI): 44.8 (19.2, 70.4), p = 0.025 among participants with, but not without, ASCVD 2.16 (−6.74, 11.5), p = 1.000. Non-esterified cis-palmitoleic acid (16:1n-7c) was positively associated with FMD 19.7 (8.34, 31.0), p = 0.024 among participants without, but not with ASCVD. No significant associations between NEFAs and estimated plaque thickness were observed. Conclusions: In older adults, serum non-esterified CLA and palmitoleic acid were positively associated with carotid IMT and FMD, respectively, suggesting potential modifiable biomarkers for arteriopathy.
The relationship between thyroid dysfunction and measures of myocardial disease in older individuals remains to be defined.
To evaluate the impact of thyroid dysfunction on structure and function of ...the left-heart chambers and blood markers of cardiac disease.
Cross-sectional analysis.
The Cardiovascular Health Study, a community-based cohort of older individuals recruited from four urban areas in the United States.
Of 3163 participants studied, 2477 were euthyroid, 465 had subclinical hypothyroidism (SCH), 47 overt hypothyroidism (OH), 45 endogenous (endo) subclinical hyperthyroidism (endo-SCT), and 129 had exogenous (exo) SCT due to thyroid hormone supplementation.
Clinical evaluation, blood sampling and biomarker measurement, 2-dimensional and speckle-tracking echocardiography.
Left heart myocardial deformation, circulating biomarkers of diastolic overload (NT-proBNP), fibrosis (sST2, gal-3), and cardiomyocyte injury (hs-cTnT).
SCH was associated with higher NT-proBNP (beta = 0.17, p = 0.004), whereas OH was associated with higher hs-cTnT (beta = 0.29, p = 0.005). There were also suggestive associations of SCH with higher sST2, as well as endo-SCT with higher gal-3 and lower (worse) left atrial reservoir strain. Left ventricular longitudinal strain and end-diastolic strain rate did not differ significantly from euthyroid participants in SCH, OH, or exo-SCT.
In this free-living elderly cohort, subclinical and overt hypothyroidism were associated with abnormalities of blood biomarkers consistent with diastolic overload and myocardial necrosis respectively, whereas subclinical hyperthyroidism tended to be associated with myocardial fibrosis and decreased left atrial strain. Our findings could represent stage B heart failure and illuminate distinct aspects of the pathobiology of heart disease related to thyroid gland dysfunction with potential clinical implications.
Aging is associated with an increase in circulating inflammatory factors. One, the cytokine stromal cell-derived factor 1 (SDF-1 or CXCL12), is critical to stem cell mobilization, migration, and ...homing as well as to bone marrow stem cell (BMSC), osteoblast, and osteoclast function. SDF-1 has pleiotropic roles in bone formation and BMSC differentiation into osteoblasts/osteocytes, and in osteoprogenitor cell survival. The objective of this study was to examine the association of plasma SDF-1 in participants in the cardiovascular health study (CHS) with bone mineral density (BMD), body composition, and incident hip fractures. In 1536 CHS participants, SDF-1 plasma levels were significantly associated with increasing age (
p
< 0.01) and male gender (
p
= 0.04), but not with race (
p
= 0.63). In multivariable-adjusted models, higher SDF-1 levels were associated with lower total hip BMD (
p
= 0.02). However, there was no significant association of SDF-1 with hip fractures (
p
= 0.53). In summary, circulating plasma levels of SDF-1 are associated with increasing age and independently associated with lower total hip BMD in both men and women. These findings suggest that SDF-1 levels are linked to bone homeostasis.
Mildly reduced renal function and elevated urine protein levels are each prospectively associated with hip fracture risk in older adults. Here we determine whether these markers are associated with ...reduced appendicular muscle performance.
We prospectively examined the associations of urine albumin:creatinine ratio (ACR) and reduced estimated glomerular filtration rate (eGFR) with longitudinal changes in grip strength and gait speed >2 years in 2317 older community-dwelling men and women (median age 77 years). The median ACR was 9.8 interquartile range (IQR) 5.40-21.50 mg/g creatinine and the median eGFR was 71.6 (IQR 59.1-83.56) mL/min/1.73 m
. Models were adjusted for demographic factors, clinical history and biochemical measures in four candidate pathways: diabetes, oxidative stress, inflammation and fibrosis.
In demographic- and covariate-adjusted models, a 2-fold higher baseline urine ACR was associated with longitudinal changes of -0.17 kg 95% confidence interval (CI) -0.29 to -0.06) in grip strength and -1.10 cm/s (95% CI -1.67 to -0.53) gait speed per year. Corresponding estimates for a 10 mL/min/1.73 m
lower baseline eGFR were -0.13 kg (95% CI -0.23 to -0.04) and -0.89 cm/s (95% CI -1.37 to -0.40), respectively. The associations of a 2-fold higher baseline ACR and a 10 mL/min/1.73 m
lower baseline eGFR using cystatin C with grip strength and gait speed were equivalent to ∼1.2-1.9 additional years of age. Adjustment for covariates in candidate pathways did not attenuate these estimates.
In older adults, higher ACR and lower eGFR are potential risk factors for a decline of physical performance >2 years.
Abstract
C-reactive protein (CRP) is a circulating biomarker indicative of systemic inflammation. We aimed to evaluate genetic associations with CRP levels among non-European-ancestry populations ...through discovery, fine-mapping and conditional analyses. A total of 30 503 non-European-ancestry participants from 6 studies participating in the Population Architecture using Genomics and Epidemiology study had serum high-sensitivity CRP measurements and ∼200 000 single nucleotide polymorphisms (SNPs) genotyped on the Metabochip. We evaluated the association between each SNP and log-transformed CRP levels using multivariate linear regression, with additive genetic models adjusted for age, sex, the first four principal components of genetic ancestry, and study-specific factors. Differential linkage disequilibrium patterns between race/ethnicity groups were used to fine-map regions associated with CRP levels. Conditional analyses evaluated for multiple independent signals within genetic regions. One hundred and sixty-three unique variants in 12 loci in overall or race/ethnicity-stratified Metabochip-wide scans reached a Bonferroni-corrected P-value <2.5E−7. Three loci have no (HACL1, OLFML2B) or only limited (PLA2G6) previous associations with CRP levels. Six loci had different top hits in race/ethnicity-specific versus overall analyses. Fine-mapping refined the signal in six loci, particularly in HNF1A. Conditional analyses provided evidence for secondary signals in LEPR, IL1RN and HNF1A, and for multiple independent signals in CRP and APOE. We identified novel variants and loci associated with CRP levels, generalized known CRP associations to a multiethnic study population, refined association signals at several loci and found evidence for multiple independent signals at several well-known loci. This study demonstrates the benefit of conducting inclusive genetic association studies in large multiethnic populations.
It is common in longitudinal studies for scheduled visits to be accompanied by as-needed visits due to medical events occurring between scheduled visits. If the timing of these as-needed visits is ...related to factors that are associated with the outcome but are not among the regression model covariates, naively including these as-needed visits in the model yields biased estimates. In this paper, the authors illustrate and discuss the key issues pertaining to inverse intensity rate ratio (IIRR)-weighted generalized estimating equations (GEE) methods in the context of a study of Kenyan mothers infected with human immunodeficiency virus type 1 (1999–2005). The authors estimated prevalences and prevalence ratios for morbid conditions affecting the women during a 1-year postpartum follow-up period. Of the 484 women under study, 62% had at least 1 as-needed visit. Use of a standard GEE model including both scheduled and unscheduled visits predicted a pneumonia prevalence of 2.9% (95% confidence interval: 2.3%, 3.5%), while use of the IIRR-weighted GEE predicted a prevalence of 1.5% (95% confidence interval: 1.2%, 1.8%). The estimate obtained using the IIRR-weighted GEE approach was compatible with estimates derived using scheduled visits only. These results highlight the importance of properly accounting for informative follow-up in these studies.
Background Significant associations have been reported between serum total nonesterified fatty acid (NEFA) concentrations and coronary heart disease (CHD) mortality and incident nonfatal myocardial ...infarction (MI) in some prospective cohort studies. Little is known about whether individual or subclasses (saturated, polyunsaturated n-6 and n-3, and
fatty acids) of serum NEFAs relate to CHD mortality and nonfatal MI. Methods and Results CHS (Cardiovascular Health Study) participants (N=1681) who had no history of MI, angina, or revascularization or were free of MI at baseline (1996-1997) were included. NEFAs were quantified using gas chromatography. Cox regression analysis was used to evaluate associations of 5 subclasses and individual NEFAs with CHD composite (CHD mortality and nonfatal MI), CHD mortality, and incident nonfatal MI. During a median follow-up of 11.7 years, 266 cases of CHD death and 271 cases of nonfatal MI occurred. In the fully adjusted model, no significant associations were identified between individual NEFA and CHD composite. Exploratory analyses indicated that lauric acid (12:0) was negatively associated (hazard ratio HR, 0.76; 95% CI, 0.59-0.98;
=0.0328) and dihomo-γ-linolenic acid (20:3n-6) was positively associated with CHD mortality (HR, 1.34; 95% CI, 1.02-1.76;
=0.0351). Elaidic acid (18:1n-7
) was positively associated with incident nonfatal MI (HR, 1.46; 95% CI, 1.01-2.12;
=0.0445). No significant associations were observed for NEFA subclass and any outcomes. Conclusions In CHS participants, 2 NEFAs, dihomo-γ-linolenic and elaidic acids, were positively associated with CHD mortality and nonfatal MI, respectively, suggesting potential susceptibility biomarkers for risks of CHD mortality and nonfatal MI.
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