Age- and sex-specific changes in visceral fat mass throughout the life-span.

OBJECTIVE: Visceral fat mass (VFM) is a risk factor for cardiovascular diseases, type 2 diabetes mellitus, and malignancy; however, normative data are limited. The aim of this study was to provide reference data for VFM from a large, apparently healthy Caucasian adult population. METHODS: Volunteers aged 20 to 93 years from the Copenhagen City Heart Study had a standardized whole-body dual-energy x-ray absorptiometry scan performed using the iDXA (GE Lunar). Total and regional fat mass was measured. VFM was quantified using the CoreScan application. RESULTS: A total of 1277 participants were included (708 women, mean [SD], age: 56 [19] years, height: 1.66 [0.07] m, BMI: 24.64 [4.31] kg/m2 ; and 569 men, age: 57 [18] years, height: 1.80 [0.07] m, BMI: 25.99 [3.86] kg/m2 ). Increased VFM was positively correlated with age in both sexes. Men had significantly higher VFM in mass (g) after normalization to body size (m2 ) and total fat mass (p < 0.001). VFM increased more in women with high values of the android/gynoid ratio. CONCLUSIONS: Normative data of VFM from a large, healthy Danish cohort aged 20 to 93 years are presented. VFM increased with age in both sexes, but men had significantly higher VFM compared with women with the same BMI, body fat percentage, and fat mass index.

Multimodality Imaging in Cranial Giant Cell Arteritis: First Experience with High-Resolution T1-Weighted 3D Black Blood without Contrast Enhancement Magnetic Resonance Imaging.

In order to support or refute the clinical suspicion of cranial giant cell arteritis (GCA), a supplemental imaging modality is often required. High-resolution black blood Magnetic Resonance Imaging (BB MRI) techniques with contrast enhancement can visualize artery wall inflammation in GCA. We compared findings on BB MRI without contrast enhancement with findings on 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography/low-dose computed tomography (2-[18F]FDG PET/CT) in ten patients suspected of having GCA and in five control subjects who had a 2-[18F]FDG PET/CT performed as a routine control for malignant melanoma. BB MRI was consistent with 2-[18F]FDG PET/CT in 10 out of 10 cases in the group with suspected GCA. In four out of five cases in the control group, the BB MRI was consistent with 2-[18F]FDG PET/CT. In this small population, BB MRI without contrast enhancement shows promising performance in the diagnosis of GCA, and might be an applicable imaging modality in patients.

Kidney oxygenation, perfusion and blood flow in people with and without type 1 diabetes.

Background: We used magnetic resonance imaging (MRI) to study kidney energetics in persons with and without type 1 diabetes (T1D). Methods: In a cross-sectional study, 15 persons with T1D and albuminuria and 15 non-diabetic controls (CONs) underwent multiparametric MRI (3 Tesla Philips Scanner) to quantify renal cortical and medullary oxygenation (R2*, higher values correspond to higher deoxyhaemoglobin concentration), renal perfusion (arterial spin labelling) and renal artery blood flow (phase contrast). Analyses were adjusted for age, sex, systolic blood pressure, plasma haemoglobin, body mass index and estimated glomerular filtration rate (eGFR). Results: Participants with T1D had a higher median (Q1; Q3) urine albumin creatinine ratio (UACR) than CONs [46 (21; 58) versus 4 (3; 6) mg/g; P < .0001] and a lower mean ± SD eGFR (73 ± 32 mL/min/1.73 m2 versus 88 ± 15 mL/min/1.73 m2;  P = .12), although not significantly. Mean medullary R2* was lower in T1D (34 ± 6/s versus 38 ± 5/s; P < .01) corresponding to a higher oxygenation. R2* was not different in the cortex. Cortical perfusion was lower in T1D (163 ± 40 versus 224 ± 49 mL/100 g/min; P < .001). Renal artery blood flow was lower in T1D than in CONs (360 ± 130 versus 430 ± 113 mL/min; P = .05). In T1D, lower cortical oxygenation and renal artery blood flow were both associated with higher UACR and lower eGFR (P < .05). Conclusions: Participants with T1D and albuminuria exhibited higher medullary oxygenation than CONs, despite lower cortical perfusion and renal artery blood flow. This might reflect perturbed kidney energetics leading to a higher setpoint of medullary oxygenation in T1D. Lower cortical oxygenation and renal artery blood flow were associated with higher UACR and lower eGFR in T1D.

Changes in systemic GDF15 across the adult lifespan and their impact on maximal muscle power: the Copenhagen Sarcopenia Study.

BACKGROUND: Although growth differentiation factor 15 (GDF15) is known to increase with disease and is associated with low physical performance, the role of GDF15 in normal ageing is still not fully understood. Specifically, the influence of circulating GDF15 on impairments in maximal muscle power (a major contributor to functional limitations) and the underlying components has not been investigated. METHODS: Data from 1305 healthy women and men aged 20 to 93 years from The Copenhagen Sarcopenia Study were analysed. Circulating levels of GDF15 and markers of inflammation (tumor necrosis factor-alpha, interleukin-6, and high-sensitivity C-reactive protein) were measured by ELISA (R&D Systems) and multiplex bead-based immunoassays (Bio-Rad). Relative (normalized to body mass), allometric (normalized to height squared), and specific (normalized to leg muscle mass) muscle power were assessed by the Nottingham power rig [leg extension power (LEP)] and the 30 s sit-to-stand (STS) muscle power test. Total body fat, visceral fat, and leg lean mass were assessed by dual energy X-ray absorptiometry. Leg skeletal muscle index was measured as leg lean mass normalized to body height squared. RESULTS: Systemic levels of GDF15 increased progressively as a function of age in women (1.1 ± 0.4 pg·mL-1 ·year-1 ) and men (3.3 ± 0.6 pg·mL-1 ·year-1 ) (both P < 0.05). Notably, GDF15 increased at a faster rate from the age of 65 years in women (11.5 ± 1.2 pg·mL-1 ·year-1 , P < 0.05) and 70 years in men (19.3 ± 2.3 pg·mL-1 ·year-1 , P < 0.05), resulting in higher GDF15 levels in men compared with women above the age of 65 years (P < 0.05). Independently of age and circulatory markers of inflammation, GDF15 was negatively correlated to relative STS power (P < 0.05) but not LEP, in both women and men. These findings were mainly explained by negative associations of GDF15 with specific STS power in women and men (both P < 0.05). CONCLUSIONS: A J-shaped relationship between age and systemic GDF15 was observed, with men at older age showing steeper increases and elevated GDF15 levels compared with women. Importantly, circulating GDF15 was independently and negatively associated with relative STS power, supporting the potential role of GDF15 as a sensitive biomarker of frailty in older people.

Associations between inflammatory markers, body composition, and physical function: the Copenhagen Sarcopenia Study.

BACKGROUND: Chronic low-grade inflammation has been suggested as one of the key elements in the development of sarcopenia, but in contrast to disease-related loss of muscle mass, the role of chronic low-grade inflammation in age-related (primary) sarcopenia is still not clear. The aim of this study was to investigate low-grade inflammation in relation to age and the potential association between inflammatory biomarkers and body composition, muscle strength and physical performance in a healthy Danish cohort. METHODS: There were 1160 generally healthy men and women (range: 22-93 years) included. Appendicular lean mass (ALM) and visceral fat normalized to height (kg/m2 ) was assessed by dual-energy X-ray absorptiometry (iDXA, GE Lunar). Muscle strength and physical performance were evaluated by handgrip strength (HGS), 30 s sit-to-stand performance, and maximal gait speed (GS). Systemic levels of TNF-α, IL-6, IL-1ß, IL-4, IL-13, and IFN-γ were measured using multiplex bead-based immunoassays (Bio-Rad). hsCRP was assessed using latex particle-enhanced immunoturbidimetric assays (Roche Diagnostics). RESULTS: With age, ALM/h2 , HGS, sit-to-stand performance and GS decreased, whereas visceral fat/h2 increased in both men and women (P < 0.05). Systemic levels of hsCRP, TNF-α, IL-4, and IFN-γ increased with age in men and women (P < 0.05), while IL-1ß increased in women only (P < 0.01). Higher levels of hsCRP were associated with lower ALM/h2 in elderly (≥65 years) men and women (P < 0.001). Higher levels of hsCRP were associated with lower handgrip strength in elderly women (P < 0.05) whereas higher levels of hsCRP was not associated with lower HGS in elderly men (P = 0.056). Higher levels of hsCRP were associated with lower GS (P < 0.05), whereas IFN-γ was positively associated with GS in elderly women (P < 0.05), but not elderly men. Visceral fat index was positively associated with hsCRP in elderly men and women (P < 0.001). Compared with elderly with normal HGS, elderly men and women with low HGS displayed higher levels of TNF-α and hsCRP (P < 0.05). CONCLUSIONS: With age, systemic levels of hsCRP, TNF-α, IL-4, and IFN-γ increased, with hsCRP and TNF-α being especially elevated in more physically frail elderly supporting the association between low-grade systemic inflammation and poor physical function. In contrast, only high levels of hsCRP were weakly associated with low muscle mass and positively associated with visceral fat and low physical function, suggesting that chronic low-grade inflammation is not the main driver of age-related loss of muscle mass as previously suggested.

A Nordic survey of CT doses in hybrid PET/CT and SPECT/CT examinations.

BACKGROUND: Computed tomography (CT) scans are routinely performed in positron emission tomography (PET) and single photon emission computed tomography (SPECT) examinations globally, yet few surveys have been conducted to gather national diagnostic reference level (NDRL) data for CT radiation doses in positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/computed tomography (SPECT/CT). In this first Nordic-wide study of CT doses in hybrid imaging, Nordic NDRL CT doses are suggested for PET/CT and SPECT/CT examinations specific to the clinical purpose of CT, and the scope for optimisation is evaluated. Data on hybrid imaging CT exposures and clinical purpose of CT were gathered for 5 PET/CT and 8 SPECT/CT examinations via designed booklet. For each included dataset for a given facility and scanner type, the computed tomography dose index by volume (CTDIvol) and dose length product (DLP) was interpolated for a 75-kg person (referred to as CTDIvol,75kg and DLP75kg). Suggested NDRL (75th percentile) and achievable doses (50th percentile) were determined for CTDIvol,75kg and DLP75kg according to clinical purpose of CT. Differences in maximum and minimum doses (derived for a 75-kg patient) between facilities were also calculated for each examination and clinical purpose. RESULTS: Data were processed from 83 scanners from 43 facilities. Data were sufficient to suggest Nordic NDRL CT doses for the following: PET/CT oncology (localisation/characterisation, 15 systems); infection/inflammation (localisation/characterisation, 13 systems); brain (attenuation correction (AC) only, 11 systems); cardiac PET/CT and SPECT/CT (AC only, 30 systems); SPECT/CT lung (localisation/characterisation, 12 systems); bone (localisation/characterisation, 30 systems); and parathyroid (localisation/characterisation, 13 systems). Great variations in dose were seen for all aforementioned examinations. Greatest differences in DLP75kg for each examination, specific to clinical purpose, were as follows: SPECT/CT lung AC only (27.4); PET/CT and SPECT/CT cardiac AC only (19.6); infection/inflammation AC only (18.1); PET/CT brain localisation/characterisation (16.8); SPECT/CT bone localisation/characterisation (10.0); PET/CT oncology AC only (9.0); and SPECT/CT parathyroid localisation/characterisation (7.8). CONCLUSIONS: Suggested Nordic NDRL CT doses are presented according to clinical purpose of CT for PET/CT oncology, infection/inflammation, brain, PET/CT and SPECT/CT cardiac, and SPECT/CT lung, bone, and parathyroid. The large variation in doses suggests great scope for optimisation in all 8 examinations.

The Copenhagen Sarcopenia Study: lean mass, strength, power, and physical function in a Danish cohort aged 20-93 years.

BACKGROUND: Despite no international consensus on the diagnostic criteria for sarcopenia, low lean mass, muscle strength, and physical function are important risk factors for disability, frailty, and mortality in older individuals, as well as in a wide range of patients with muscle loss. Here, we provide a population-based reference material of total and regional lean body mass, muscle strength/power parameters, and physical function in a healthy cohort of Danish men and women across the lifespan. METHODS: Volunteers aged 20-93 years from the Copenhagen City Heart Study were invited to establish a Danish reference material (Copenhagen Sarcopenia Study) on lean mass characteristics [appendicular lean mass (ALM), iDXA, GE Lunar], muscle function [handgrip strength (HGS), Jamar dynamometer and leg extension power (LEP), Nottingham Power Rig], and physical function [30 s sit-to-stand test (STS), 10-m maximal and habitual gait speed (GS)]. RESULTS: A total of 1305 participants [729 women (age: 56.4 ± 18.9 years, height: 1.66 ± 0.01 m, body mass index: 24.6 ± 4.3 kg/m2 and 576 men, age: 57.0 ± 17.5 years, height: 1.80 ± 0.07 m, body mass index: 26.0 ± 3.9 kg/m2 ] completed all measurements and were included in the present analysis. Lean mass characteristics (TLM, ALM, and ALM/h2 ) decreased with increasing age in both men and women (P < 0.001). Men demonstrated larger absolute and relative total ALM and higher HGS and LEP compared with women at all age intervals (P < 0.001). HGS and LEP decreased progressively with age in both men and women (P < 0.01); 30 s STS performance, habitual GS, and maximal GS decreased at an accellerated rate of decline with increasing age in both men and women (P < 0.001). Habitual GS was reduced in men and women aged ≥70 years, while maximal GS was reduced from the age of ≥60 years compared with young adults (P < 0.001). Regardless of sex, 30 s STS was reduced from the age of ≥50 years compared with the young reference group (P < 0.001) CONCLUSIONS: While the power-based measurements (LEP and 30 s STS) started to decline already at age +50 years, less power-based parameters (GS and HGS) and lean mass characteristics (TLM, ALM, and ALM/h2 ) remained unaltered until after the age of +70 years. Notably, the cut-off thresholds derived in the present study differed from earlier reference data, which underlines the importance of obtaining updated and local reference materials.