Longitudinal changes in radial bone density in older men

Overton, T.R.; Basu, T.K.

doi:10.1038/sj.ejcn.1600703

Cited by 18 publications

(8 citation statements)

References 9 publications

(21 reference statements)

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“…As in humans, [42][43][44] decreases in bone volume and trabecular number are part of the natural aging process in C57BL/6 mice, [45][46][47][48] and our histology and CT analyses indicate that the abnormal bone phenotype in iPLA 2 ␤-null mice is accelerated in the absence of iPLA 2 ␤. Examination of bone resorption parameters reveal no accompanying increase in osteoclast abundance or activity, suggesting that bone resorption, most likely is not responsible for bone loss in iPLA 2 ␤-null mice.…”

Section: Discussionmentioning

confidence: 99%

Age-Related Changes in Bone Morphology Are Accelerated in Group VIA Phospholipase A2 (iPLA2β)-Null Mice

Ramanadham

Yarasheski

Silva

et al. 2008

The American Journal of Pathology

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Phospholipases A 2 (PLA 2 ) hydrolyze the sn؊2 fatty acid substituent, such as arachidonic acid, from phospholipids, and arachidonate metabolites are recognized mediators of bone modeling. We have previously generated knockout (KO) mice lacking the group VIA PLA 2 (iPLA 2 ␤), which participates in a variety of signaling events; iPLA 2 ␤ mRNA is expressed in bones of wild-type (WT) but not KO mice. Cortical bone size, trabecular bone volume, bone mineralizing surfaces, and bone strength are similar in WT and KO mice at 3 months and decline with age in both groups, but the decreases are more pronounced in KO mice. The lower bone mass phenotype observed in KO mice is not associated with an increase in osteoclast abundance/activity or a decrease in osteoblast density, but is accompanied by an increase in bone marrow fat. Relative to WT mice, undifferentiated bone marrow stromal cells (BMSCs) from KO mice express higher levels of PPAR-␥ and lower levels of Runx2 mRNA, and this correlates with increased adipogenesis and decreased osteogenesis in BMSCs from these mice. In summary, our studies indicate that age-related losses in bone mass and strength are accelerated in iPLA 2 ␤-null mice. Because adipocytes and osteoblasts share a common mesenchymal stem cell origin, our findings suggest that absence of iPLA 2 Bioactive arachidonic acid (AA) metabolites (eicosanoids) generated by the actions of various oxygenases, such as the 5-lipoxygenase (5-LO) and cyclooxygenase (COX) isozymes, are important mediators of bone remodeling. The 5-LO products leukotrienes and 5-HETE (hydroxyeicosatetraenoic acid) function as negative modulators of bone formation by inhibiting osteoblast differentiation and bone formation.1 In contrast, prostaglandins (PGs), eg, PGE 2 , derived from COX metabolism of AA enhance bone formation and mass by increasing osteoblast replication and differentiation and/or by inhibiting osteoclastic resorption, [2][3][4][5]

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Section: Discussionmentioning

confidence: 99%

Age-Related Changes in Bone Morphology Are Accelerated in Group VIA Phospholipase A2 (iPLA2β)-Null Mice

Ramanadham

Yarasheski

Silva

et al. 2008

The American Journal of Pathology

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“…Overton & Basu (1999) (125) Jaques et al (1997) (140) Shea et al (2009) (290) Dawson-Hughes et al (1997) (133) Iannuzzi-Sucich et al (2002) (138) Hill et al (2010) (137) Johnson et al (2008) (141) Subtotal (I 2 = 99•0 %, P = 0•000) potential explanation for this pattern in the Middle East/Africa region could be that children/adolescents from this region generally spend more time outdoors compared with the other age groups (e.g. indoor working by the adult population) (22) .…”

Section: Malementioning

confidence: 99%

A systematic review of vitamin D status in populations worldwide

et al. 2013

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Vitamin D deficiency is associated with osteoporosis and is thought to increase the risk of cancer and CVD. Despite these numerous potential health effects, data on vitamin D status at the population level and within key subgroups are limited. The aims of the present study were to examine patterns of 25-hydroxyvitamin D (25(OH)D) levels worldwide and to assess differences by age, sex and region. In a systematic literature review using the Medline and EMBASE databases, we identified 195 studies conducted in forty-four countries involving more than 168 000 participants. Mean population-level 25(OH)D values varied considerably across the studies (range 4·9-136·2 nmol/l), with 37·3 % of the studies reporting mean values below 50 nmol/l. The highest 25(OH)D values were observed in North America. Although age-related differences were observed in the Asia/Pacific and Middle East/Africa regions, they were not observed elsewhere and sex-related differences were not observed in any region. Substantial heterogeneity between the studies precluded drawing conclusions on overall vitamin D status at the population level. Exploratory analyses, however, suggested that newborns and institutionalised elderly from several regions worldwide appeared to be at a generally higher risk of exhibiting lower 25(OH)D values. Substantial details on worldwide patterns of vitamin D status at the population level and within key subgroups are needed to inform public health policy development to reduce risk for potential health consequences of an inadequate vitamin D status. Key words: Vitamin D: Populations: Public healthVitamin D plays an important role in bone mineralisation and other metabolic processes in the human body such as Ca and phosphate homeostasis and skeletal growth (1,2) . Vitamin D deficiency, for example, causes rickets in children, leading to skeletal abnormalities, short stature, delayed development or failure to thrive (3) . In adults, low values of vitamin D are associated with osteomalacia, osteopenia, osteoporosis and subsequent risk of fractures (1) . In addition to beneficial effects on musculoskeletal health, observational studies have suggested that low 25-hydroxyvitamin D (25(OH)D) values are associated with an increased risk for several extraskeletal diseases including cancer, infections, autoimmune diseases and CVD (4) . In light of the global ageing population (5) ,an almost fourfold increase in osteoporotic hip fractures since 1990 (6) and the possible risk of other chronic diseases, patterns of low 25(OH)D levels are of substantial public health interest. Vitamin D status is traditionally measured through assays of 25(OH)D, the major circulating form of vitamin D (7) . Although 25(OH)D levels below 25 nmol/l have been associated with disorders of bone metabolism (8) and are used to indicate severe vitamin D deficiency, the threshold for defining adequate stores of vitamin D in humans has not been established clearly (9) . The Institute of Medicine has suggested, for example, that approximately 97·5 % of t...

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“…Bone loss appears to begin near age 40 and continues throughout life, with an apparent acceleration after age 60 [1][2][3]. It is well-known that the bone loss results in the increased porosity in cortical and trabecular bones, decreased mineralization, and ultimately increases fracture risk [2,4].…”

Section: Introductionmentioning

confidence: 99%