Bone mineral density and chronic lung disease mortality: the Rotterdam study

Context: Low bone mineral density (BMD) has been associated with increased all-cause mortality. Cause-specific mortality studies have been controversial. Objective: The aim of the study was to investigate associations between BMD and all-cause mortality and in-depth cause-specific mortality. Design and Setting: We studied two cohorts from the prospective Rotterdam Study (RS), initiated in 1990 (RS-I) and 2000 (RS-II) with average follow-up of 17.1 (RS-I) and 10.2 (RS-II) years until January 2011. Baseline femoral neck BMD was analyzed in SD values. Deaths were classified according to International Classification of Diseases into seven groups: cardiovascular diseases, cancer, infections, external, dementia, chronic lung diseases, and other causes. Gender-stratified Cox and competing-risks models were adjusted for age, body mass index, and smoking. Participants: The study included 5779 subjects from RS-I and 2055 from RS-II. Main Outcome Measurements: We measured all-cause and cause-specific mortality. Results: A significant inverse association between BMD and all-cause mortality was found in males [expressed as hazard ratio (95% confidence interval)]: RS-I, 1.07 (1.01-1.13), P = .020; RS-II, 1.31 (1.12-1.55), P = .001); but it was not found in females: RS-I, 1.05 (0.99-1.11), P = .098; RS-II, 0.91 (0.74-1.12), P = .362. An inverse association with chronic lung disease mortality was found in males [RS-I, 1.75 (1.34-2.29), P < .001; RS-II, 2.15 (1.05-4.42), P = .037] and in RS-I in females [1.72 (1.16-2.57); P = .008], persisting after multiple adjustments and excluding prevalent chronic obstructive pulmonary disease. A positive association between BMD and cancer mortality was detected in females in RS-I [0.89 (0.80-0.99); P = .043]. No association was found with cardiovascular mortality. Conclusions: BMD is inversely associated with mortality. The strong association of BMD with chronic lung disease mortality is a novel finding that needs further analysis to clarify underlying mechanisms

Large meta-analysis of genome-wide association studies identifies five loci for lean body mass

Lean body mass, consisting mostly of skeletal muscle, is important for healthy aging. We performed a genome-wide association study for whole body (20 cohorts of European ancestry with n = 38,292) and appendicular (arms and legs) lean body mass (n = 28,330) measured using dual energy X-ray absorptiometry or bioelectrical impedance analysis, adjusted for sex, age, height, and fat mass. Twenty-one single-nucleotide polymorphisms were significantly associated with lean body mass either genome wide (p < 5 × 10−8) or suggestively genome wide (p < 2.3 × 10−6). Replication in 63,475 (47,227 of European ancestry) individuals from 33 cohorts for whole body lean body mass and in 45,090 (42,360 of European ancestry) subjects from 25 cohorts for appendicular lean body mass was successful for five single-nucleotide polymorphisms in/near HSD17B11, VCAN, ADAMTSL3, IRS1, and FTO for total lean body mass and for three single-nucleotide polymorphisms in/near VCAN, ADAMTSL3, and IRS1 for appendicular lean body mass. Our findings provide new insight into the genetics of lean body mass

The physiology of endocrine systems with ageing

During ageing, the secretory patterns of the hormones produced by the hypothalamic-pituitary axis change, as does the sensitivity of the axis to negative feedback by end hormones. Additionally, glucose homoeostasis tends towards disequilibrium with increasing age. Along with these endocrine alterations, a loss of bone and muscle mass and strength occurs, coupled with an increase in fat mass. In addition, ageing-induced effects are difficult to disentangle from the influence of other factors that are common in older people, such as chronic diseases, inflammation, and low nutritional status, all of which can also affect endocrine systems. Traditionally, the decrease in hormone activity during the ageing process has been considered to be detrimental because of the related decline in bodily functions. The concept of hormone replacement therapy was suggested as a therapeutic intervention to stop or reverse this decline. However, clearly some of these changes are a beneficial adaptation to ageing, whereas hormonal intervention often causes important adverse effects. In this paper, we discuss the effects of age on the different hypothalamic-pituitary-hormonal organ axes, as well as age-related changes in calcium and bone metabolism and glucose homoeostasis

Early-Onset Osteoporosis

Publisher Copyright: © 2021, The Author(s).Osteoporosis is a skeletal disorder with enhanced bone fragility, usually affecting the elderly. It is very rare in children and young adults and the definition is not only based on a low BMD (a Z-score < − 2.0 in growing children and a Z-score ≤ − 2.0 or a T-score ≤ − 2.5 in young adults) but also on the occurrence of fragility fractures and/or the existence of underlying chronic diseases or secondary factors such as use of glucocorticoids. In the absence of a known chronic disease, fragility fractures and low BMD should prompt extensive screening for secondary causes, which can be found in up to 90% of cases. When fragility fractures occur in childhood or young adulthood without an evident secondary cause, investigations should explore the possibility of an underlying monogenetic bone disease, where bone fragility is caused by a single variant in a gene that has a major role in the skeleton. Several monogenic forms relate to type I collagen, but other forms also exist. Loss-of-function variants in LRP5 and WNT1 may lead to early-onset osteoporosis. The X-chromosomal osteoporosis caused by PLS3 gene mutations affects especially males. Another recently discovered form relates to disturbed sphingolipid metabolism due to SGMS2 mutations, underscoring the complexity of molecular pathology in monogenic early-onset osteoporosis. Management of young patients consists of treatment of secondary factors, optimizing lifestyle factors including calcium and vitamin D and physical exercise. Treatment with bone-active medication should be discussed on a personalized basis, considering the severity of osteoporosis and underlying disease versus the absence of evidence on anti-fracture efficacy and potential harmful effects in pregnancy.Peer reviewe

Bone health and coronary artery calcification: The Rotterdam Study

Objectives: Vascular calcification has been associated inconsistently to low bone mineral density and fractures. The aims of the present study were to investigate the associations between coronary artery calcification (CAC) and BMD change, BMD and fracture risk in elderly subjects of the population-based Rotterdam Study. Methods: BMD was assessed through dual-energy X-ray absorptiometry and CAC through Electron-Beam Computed Tomography in 582 men and 694 women. We investigated the associations between BMD change (6.4 years follow-up) and CAC at follow-up and between BMD and CAC (measured simultaneously). In sensitivity analyses we stratified analyses for estradiol levels in women. The association between CAC and fracture risk (9 years follow-up) was tested through competing-risks models. Models were sex-stratified and adjusted for age, body mass index, smoking, bisphosphonate use and age at menopause. Results: There was no association between BMD change and CAC in men. In women, each 1% increase in annual BMD loss was significantly associated with higher follow-up CAC [β = 0.22 (0.06-0.38), p. =. 0.006; prevalence ratio: 4%]. Stratified analyses showed significant associations between BMD loss and follow-up CAC only in women with lower estradiol levels. We found no association between CAC and fracture risk and no association between BMD and CAC cross-sectionally. Conclusions: BMD loss was associated with higher follow-up CAC in women, which might be related to low estrogen levels. No association between CAC and BMD or fracture risk was found. Further studies are required to elucidate the mechanisms that might underlie the association between BMD change and coronary calcification in women

Hydroxychloroquine decreases human MSC-derived osteoblast differentiation and mineralization in vitro

We recently showed that patients with primary Sjögren Syndrome (pSS) have significantly higher bone mineral density (BMD) compared to healthy controls. The majority of those patients (69%) was using hydroxychloroquine (HCQ), which may have favourable effects on BMD. To study the direct effects of HCQ on human MSC-derived osteoblast activity. Osteoblasts were cultured from human mesenchymal stromal cells (hMSCs). Cultures were treated with different HCQ doses (control, 1 and 5 µg/ml). Alkaline phosphatase activity and calcium measurements were performed to evaluate osteoblast differentiation and activity, respectively. Detailed microarray analysis was performed in 5 µg/ml HCQ-treated cells and controls followed by qPCR validation. Additional cultures were performed using the cholesterol synthesis inhibitor simvastatin (SIM) to evaluate a potential mechanism of action. We showed that HCQ inhibits both MSC-derived osteoblast differentiation and mineralization in vitro. Microarray analysis and additional PCR validation reveale

Lifelong challenge of calcium homeostasis in male mice lacking TRPV5 leads to changes in bone and calcium metabolism

Trpv5 plays an important role in calcium (Ca2+) homeostasis, among others by mediating renal calcium reabsorption. Accordingly, Trpv5 deficiency strongly stresses Ca2+ homeostasis in order to maintain stable serum Ca2+. We addressed the impact of lifelong challenge of calcium homeostasis on the bone phenotype of these mice. Aging signifi

Hypophosphatasia and neuropathic pain:Related to vitamin B6 metabolism?

Hypophosphatasia (HPP) is caused by pathogenic variant(s) of the ALPL gene encoding tissue-nonspecific alkaline phosphatase (TNSALP). Diminished enzyme activity results in elevated serum concentrations of pyridoxal 5′-phosphate (PLP), the main circulating form of vitamin B6. Neuropathy has been associated with HPP, but the prevalence, pathogenesis, and symptoms remain inadequately understood. Here, we describe 5 adult HPP patients with symptoms suggestive of neuropathic pain, and speculate about potential mechanisms, related to the vitamin B6 metabolism. They reported burning pain sensations, primarily in their lower extremities. One patient was diagnosed with nociceptive pain, but he also experienced numbness and tingling sensations in his hands and feet. All patients exhibited reduced serum ALP levels along with elevated levels of serum vitamin B6 and urine phosphoethanolamine, aligning with the diagnosis of HPP. Regarding treatment, one patient received asfotase alfa which had a remarkable effect with her pain significantly decreasing already within 3 wk of starting the therapy. Another patient received nortriptyline and participated in a rehabilitation program, leading to a reduction in pain within 10 mo. Gabapentin appeared to reduce the pain in one patient, although her symptoms did not fully disappear. Mechanistically, TNSALP is essential for the transformation of PLP, the active form of vitamin B6, into pyridoxal, which is required for crossing the cell membrane and the blood-brain barrier. The deficient catalytic activity of TNSALP could lead to PLP excess extracellularly or deficiency intracellularly. Lack of PLP in the brain may result in changes to metabolites, such as adenosine, which is involved in myelin synthesis. We hypothesize that neuropathic pain could be caused by defective myelination. Alternatively, several cases of polyneuropathy linked to vitamin B6 supplementation have been reported, with a mechanism that may resemble the excess of PLP extracellularly, although the exact mechanism remains unclear.</p

Serum alkaline phosphatase can be elevated in patients with hypophosphatasia due to liver disease

Background: Hypophosphatasia (HPP) is a rare inherited disorder caused by pathogenic loss-of-function variants in the ALPL gene, encoding the tissue-nonspecific isoenzym of alkaline phosphatase (ALP; TNSALP). Low serum ALP is the biochemical hallmark of HPP, but it is unknown whether ALP levels can increase due to concurring liver disease, which may lead to a missed diagnose of HPP. We present a patient with genetically confirmed HPP, who showed a transient increase of serum ALP levels due to alcohol-induced hepatitis. Clinical report: A 71-year old man was seen at our Bone Center for surveillance of HPP. Serum ALP was always low (23 U/L; reference value: &lt;115 U/L). During follow-up, his serum ALP increased (156 U/L, further rising to 204 U/L), with concomitantly elevated serum gamma-glutamyl transferase and transaminases, and a rise in bone specific ALP (18.7 μg/L; reference value: 5.7–32.9 μg/L). This was attributed to alcohol-induced hepatitis. After refraining from alcohol intake, both serum ALP and bone specific ALP levels returned to initial low levels (30 U/L and 4.3 μg/L respectively). Conclusions: We demonstrated the history of a 71-year old patient with HPP, presenting during routine follow-up with an elevated serum ALP level up to 204 U/L due to alcohol-induced hepatitis. This case illustrates that the diagnosis of HPP can potentially be missed when ALP levels are normal or elevated due to a concomitant liver disease.</p

Phenotypic and genetic characteristics of a Dutch cohort of patients with X-linked osteoporosis due to <i>PLS3 </i>genetic variants

X-linked osteoporosis, caused by plastin 3 (PLS3) genetic variants, is a rare disease, characterized by low BMD and early-onset fractures, primarily affecting men. Our aim was to further elucidate the phenotypic characteristics, including sex-differences and genotype–phenotype analysis, in individuals with PLS3 variants. Our cohort comprises of 28 patients from 11 families, 18 men and 10 women, with a different PLS3 variant in each family. Demographic, clinical, and genetic features, imaging and laboratory tests, and treatment details were retrospectively reviewed. Men, (median age 47.0 y), demonstrated low Z-scores of the lumbar spine (−2.8 ± 1.7) and femoral neck (−1.7, IQR: −2.9-0.8). Most women (median age 49.5 y) had normal BMD, two had osteoporosis and one osteopenia. Moreover, men experienced a higher total number of fractures than women (men: 12.0, IQR: 6.7, 18.5, women: 2.0, IQR: 0.7, 5.2). Within one large family (n = 10) there was considerable heterogeneity regarding BMD and fractures, which might be explained by differences in factors like physical exercise (PE) or in (poly) genetic background. Extra-skeletal characteristics such as (mild) blue discoloration of the sclerae (men: 33.3%, women: 30.0%), joint hypermobility (44.4%, 70.0%) and skin hyperlaxity (50.0%, 20.0%) were observed. No relation was found between types and locations of variants and various clinical endpoints in men, using data from our cohort and the literature. Regarding treatment, all men and 40% of women received bone-active therapy, mostly oral bisphosphonates. Adult men demonstrated a 16.6% mean increase in the BMD of the lumbar spine (p = .03), after a median treatment duration of 6 y. In summary, this is so far the largest study of patients with X-linked osteoporosis, including an extensive genotype–phenotype analysis. A potential protective role of increasing weight-bearing PE in osteoporosis severity, as well as effects of penetrance, genetic background, or other environmental or lifestyle factors, need further study.</p