Longitudinal analysis of the relationship between physical function and mortality in ambulatory older men

Background. Low physical performance is an important characteristic of frailty and sarcopenia. In this study, we wanted to assess and compare the predictive value of physical function measurements for all-cause mortality in older men. Methods. Data are from a longitudinal study of a population-based sample of 352 ambulatory older men aged 71 to 86 at study baseline. The Rapid disability rating scale-2, 36-Item short form health survey, Hand grip strength, Five times sit-to-stand test, Standing balance, and Timed Up and Go test were determined at baseline. Associations with all-cause mortality were assessed using Cox proportional hazard analyses. Age, BMI, smoking status, education, physical activity, and cognitive status were included as confounders. Follow-up exceeded 15 years. Results. The mean age of participants was 76 ± 4.2 years. Average follow-up duration was 184 ± 2 months. Seventy-eight percent (273) of the 352 men died during follow-up, with a median survival time of 110 months. All examined physical function measurements were associated with all-cause mortality. The Timed Up and Go test was the best predictor (adjusted HR per SD increase = 1.58, 95% CI = 1.40-1.79, P < 0.001) for global mortality. Conclusions. Our findings demonstrate that physical function measurements are important in the evaluation of older persons. We encourage the use of the Timed Up and Go test as a reliable, quick and feasible screening tool in clinical settings

Thyroid hormone status within the physiological range affects bone mass and density in healthy men at the age of peak bone mass

Context: The hormonal factors involved in the regulation of peak bone mass (PBM) in men have not been fully investigated. Apart from gonadal steroids and somatotropic hormones, thyroid hormones are known to affect bone maturation and homeostasis and are additional candidate determinants of adult bone mass. Objective: We aimed to investigate between-subject physiological variation in free and total thyroid hormone concentrations, TSH, and thyroid binding globulin (TBG) in relation to parameters of bone mass, geometry, and mineral density in healthy men at the age of PBM. Design and setting: We recruited 677 healthy male siblings aged 25-45 years in a cross-sectional, population-based study. Areal and volumetric bone parameters were determined using dual-energy x-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT). Total and free thyroid hormones, TBG, and TSH were determined using immunoassays. Results: Free and total thyroid hormone concentrations were inversely associated with bone mineral density (BMD) and bone mineral content (BMC) at the hip and total body (free triiodothyronine (FT(3)), total T(3) (TT(3)), and total T(4) (TT(4))) and at the spine (FT(3)). TBG was negatively associated with BMC and areal BMD at all sites. At the radius, cortical bone area was inversely associated with TT(3), TT(4), and TBG, and trabecular bone density was inversely associated with free thyroxine, TT(4), and TBG. We observed inverse associations between cortical bone area at the mid-tibia and FT(3), TT(3), TT(4), and TBG. No associations between TSH and DXA or pQCT measurements were found. Conclusion: In healthy men at the age of PBM, between-subject variation in thyroid hormone concentrations affects bone density, with higher levels of FT(3), TT(3), TT(4), and TBG being associated with less favorable bone density and content

Association between bone mineral density and hearing loss in osteogenesis imperfecta

Objectives: The main phenotypic characteristic of osteogenesis imperfecta (OI) is bone fragility. In addition, progressive hearing loss develops in about half of the patients apparently independently from the underlying OI genotype. The hearing loss is often associated with abnormal bony changes involving the middle ear ossicles, the stapes footplate and the temporal bone surrounding the otic capsule. We aimed to investigate whether the hearing loss in OI may be related to the overall aberrant bone quality. Methods: Associations between hearing characteristics and bone mineral density were investigated in 56 adults with OI. Following audiological evaluation they were classified as presenting normal hearing (NL H), conductive/mixed hearing loss (C/M HL) or sensorineural hearing loss (SNHL). Areal bone mineral density (aBMD) was measured using lumbar spine (LS) and whole body (WB) dual X-ray absorptiometry (DXA). By means of peripheral computed tomography (pQCT) volumetric BMD (vBMD) was calculated at distal and proximal radius, providing separate results for trabecular and cortical bone. Results: Z-scores demonstrated LS aBMD, WB aBMD and trabecular vBMD to be reduced in OI adults in comparison with the healthy population. Furthermore, patients with C/M HL had lower trabecular BMD compared to those with NL H or SNHL at both whole-group and between-relatives comparisons. Conclusions: It is hypothesized that the OI patients with the lowest trabecular BMD might be more susceptible to accumulating microfractures, which interfere with the bone remodeling inhibition pathways in the temporal bone and, therefore, contribute to stapes footplate fixation and a conductive hearing loss component

Association between insulin resistance, lean mass and muscle torque/force in proximal versus distal body parts in healthy young men

Objectives:The purpose of this study was to investigate whether there is already an association of insulin resistance (IR) with muscle mass and –force/torque in an adult population and whether this relationship is the same in distal and proximal body parts. Methods: 358 Healthy young men were divided into a more insulin sensitive (MIS) (n=89) and a less insulin sensitive (LIS) group (n=89), respectively using lower and upper quartiles of HOMA-IR index (Homeostasis Model Assessment of IR). Muscle force/torque and lean mass, were compared between the two groups. Results: LIS subjects had higher absolute thigh lean mass, but not higher thigh muscle torque, resulting in a lower torque per kg muscle. In upper arm, lean mass was higher in LIS subjects, but also absolute muscle torque resulted higher. For handgrip force, the LIS and MIS group had similar results, despite a trend towards higher forearm lean mass in LIS subjects. Lean mass % of total lean mass is lower in LIS subjects in more distal body parts. Conclusions:Already in a young healthy population, IR seems to be associated with lower force/torque per muscle mass and lower lean mass % of total lean mass predominantly in more distal body parts

Association of jumping mechanography-derived indices of muscle function with tibial cortical bone geometry

Jumping mechanography has been developed to estimate maximum voluntary muscle forces. This study assessed associations of jumping mechanography-derived force and power measurements with tibial cortical bone geometry, compared to other estimates of muscle mass, size, and function. Healthy men (n = 181; 25–45 years) were recruited in a cross-sectional, population-based sibling-pair study. Muscle parameters include isokinetic peak torque of the quadriceps, DXA-derived leg lean mass, mechanography-derived peak jump force and power, and pQCT-derived mid-tibial (66 %) muscle cross-sectional area (CSA). Mid-tibial cortical bone parameters were assessed by pQCT. In age, height, and weight-adjusted analyses, jump force and power correlated positively with cortical bone area, cortical thickness, and polar strength–strain index (SSIp) (b = 0.23–0.34, p B 0.001 for force; b = 0.25–0.30, p B 0.007 for power) and inversely with endosteal circumference adjusted for periosteal circumference (ECPC) (b = -0.16, p\0.001 for force; b = -0.13, p = 0.007 for power). Force but not power correlated with cortical over total bone area ratio (b = 0.25, p = 0.002). Whereas leg lean mass correlated with all cortical parameters except cortical over total bone area ratio (b = 0.25–0.62, p B 0.004), muscle CSA only correlated with cortical bone area, periosteal circumference, and SSIp (b = 0.21–0.26, p B 0.001), and quadriceps torque showed no significant correlations with the bone parameters. Multivariate models indicated that leg lean mass was independently associated with overall bone size and strength reflected by periosteal and endosteal circumference and SSIp (b = 0.32–0.55, p B 0.004), whereas jump force was independently associated with cortical bone size reflected by ECPC, cortical thickness, and cortical over total bone area ratio (b = 0.13–0.28; p B 0.002). These data indicate that jumping mechanography provides relevant information about the relationship of muscle with bone geometry

Higher fracture prevalence and smaller bone size in patients with hEDS/HSD-a prospective cohort study

Increased fracture risk in patients with Ehlers-Danlos syndromes has been reported, but the reasons for it are incompletely understood. We aimed to investigate possible determinants of this increased risk and found that hEDS/HSD patients present with a cortical bone size deficit compared with control subjects, possibly related to lower mechanical loading. Introduction The Ehlers-Danlos syndromes (EDS) comprise a group of heritable connective tissue disorders caused by defects in the biosynthesis, secretion, and/or organization of fibrillar collagens which might impair bone strength. Our aim was to compare fracture prevalence, volumetric and areal bone mineral density (BMD), bone geometry, muscle size and the muscle-bone interaction, body composition and longitudinal changes therein between patients with hypermobile EDS (hEDS) or hypermobility spectrum disorder (HSD), and healthy control subjects. Methods Cross-sectional data comprised 39 female hEDS/HSD patients (age 41 +/- 11 years) and 43 age-matched controls. After 8 years, 27 hEDS/HSD and 17 control subjects were re-evaluated. Tibial trabecular and cortical volumetric BMD, bone mineral content (BMC), cortical bone geometry, and lower leg muscle cross-sectional area (CSA) were measured using pQCT. Body composition, areal BMD, and BMC were determined by DXA. Results At baseline, patients with hEDS/HSD presented with a smaller cortical bone area, smaller cortical thickness and muscle CSA, and a higher fracture prevalence than control subjects (all p < 0.05). No differences in areal or volumetric BMD were found. Longitudinally, muscle CSA decreased in both groups and muscle density decreased in the hEDS/HSD group (p < 0.001) whereas all bone parameters remained unchanged. Conclusion hEDS/HSD patients have a cortical bone size deficit compared with controls, possibly contributing to their increased fracture risk. They presented with decreased muscle CSA but normal bone/muscle area ratio, suggesting that this bone size deficit is likely secondary to decreased mechanical loading. Further, there were no arguments for accelerated bone loss in hEDS/HSD subjects

The influence of dairy consumption, sedentary behaviour and physical activity on bone mass in Flemish children : a cross-sectional study

Background: This cross-sectional study aimed to look for an association in young children between whole body bone mineral content (BMC) and areal bone mineral density (aBMD) and dairy consumption as well as sedentary behaviour (SB) and physical activity (PA). Moreover, we investigated whether there was an interaction effect between dairy consumption and SB or PA on BMC and aBMD. Methods: Healthy children (6-12 years) were recruited from primary schools. Body composition and whole body bone mass were measured with dual-energy X-ray absorptiometry (DXA), dairy consumption was assessed with a food frequency questionnaire (FFQ) and PA and SB with an accelerometer. In total, 272 children underwent a DXA scan. Complete FFQ data were available for 264 children and 210 children had matching data from accelerometry recordings. Regression analyses were used to study the associations between (1) BMC and aBMD and (2) dairy consumption, SB and PA, adjusting for age, gender, pubertal stage, height and body composition. Results: Dairy consumption was positively associated with whole body BMC and aBMD (absolute value as well as z-score), after correction for relevant confounders. SB was negatively associated with aBMD z-score and light PA was positively associated with both BMC and aBMD z-score. No gender differences were found. Moreover, an interaction effect between vigorous PA (VPA) and dairy consumption on aBMD (z-score) and BMC z-score was found, indicating that children with both high VPA and high dairy consumption had higher values for BMC and aBMD of the whole body minus the head. Conclusion: Already at young age, PA and dairy consumption positively influence whole body bone mass assessed by DXA. Moreover, this study indicates clearly that SB is negatively associated with whole body bone density. Promoting regular PA and sufficient dairy consumption in young children and limiting SB can be expected to positively influence their bone mass accumulation, which can help in the prevention of osteoporosis later in life