Weaker bones and white skin as adaptions to improve anthropological “fitness” for northern environments

AbstractThe vitamin D paradox relates to the lower risk of osteoporosis in people of sub-Saharan African ancestry (Blacks) compared with people of European ancestry (Whites). The paradox implies that for bone health, Blacks require less vitamin D and calcium than Whites do. Why should populations that migrated northward out of Africa have ended up needing more vitamin D than tropical Blacks? Human skin color became lighter away from the tropics to permit greater skin penetration of the UVB light that generates vitamin D. Lack of vitamin D impairs intestinal calcium absorption and limits the amount of calcium that can deposit into the protein matrix of bone, causing rickets or osteomalacia. These can cause cephalopelvic disproportion and death in childbirth. Whiter skin was more fit for reproduction in UV-light restricted environments, but natural selection was also driven by the phenotype of bone per se. Bone formation starts with the deposition of bone-matrix proteins. Mineralization of the matrix happens more slowly, and it stiffens bone. If vitamin D and/or calcium supplies are marginal, larger bones will not be as fully mineralized as smaller bones. For the same amount of mineral, unmineralized or partially mineralized bone is more easily deformed than fully mineralized bone. The evidence leads to the hypothesis that to minimize the soft bone that causes pelvic deformation, a decrease in amount of bone, along with more rapid mineralization of osteoid improved reproductive...
Source: Osteoporosis International - Category: Orthopaedics Source Type: research

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Authors: Feng C, Xiao L, Yu JC, Li DY, Tang TY, Liao W, Wang ZR, Lu AQ Abstract OBJECTIVE: By establishing osteoporosis (OP) model in rats, the specific regulatory effect of simvastatin on promoting the differentiation of mesenchymal stem cells (MSCs) into osteoblasts through the bone morphogenetic protein 2 (BMP-2)/Smads signaling pathway was investigated. MATERIALS AND METHODS: A total of 45 Sprague-Dawley rats were selected to establish the OP model by performing ovariectomy. The rats were divided into OP model group (OP group, n=15), 10-7 mmol/L simvastatin treatment group (SIM group, n=15), and normal cont...
Source: European Review for Medical and Pharmacological Sciences - Category: Drugs & Pharmacology Tags: Eur Rev Med Pharmacol Sci Source Type: research
CONCLUSIONS: MicroRNA-1286 can regulate FZD4 expression and inhibit osteogenic differentiation of hMSCs, thereby promoting the development of osteoporosis. PMID: 31957812 [PubMed - in process]
Source: European Review for Medical and Pharmacological Sciences - Category: Drugs & Pharmacology Tags: Eur Rev Med Pharmacol Sci Source Type: research
Publication date: Available online 20 January 2020Source: Life SciencesAuthor(s): Kun Tian, Yuangang Su, Jiaxin Ding, Dairong Wang, Yunfei Zhan, Yicheng Li, Jiamin Liang, Xixi Lin, Fangming Song, Ziyi Wang, Jiake Xu, Qian Liu, Jinmin ZhaoAbstractAimsPostmenopausal osteoporosis and other osteolytic bone diseases are often caused by the elevation in osteoclastogenesis and/or increased osteoclastic bone resorption, leading to excessive bone loss. Hederagenin (Hed) is a pentacyclic triterpenoid saponin extracted from various natural medicinal plants and exhibits numerous biological activities and may offer benefits against bon...
Source: Life Sciences - Category: Biology Source Type: research
AbstractSummaryUsing national insurance claims of Taiwan, we found that magnesium oxide (MgO) use is associated with an increased risk of hip fracture in the elderly. Further studies are warranted to explore the mechanisms associated with MgO use that lead to hip fracture.PurposeThe purpose of this study was to investigate the association between MgO use and hip fracture risk in the elderly (age  >  65 years).MethodsThis nationwide population-based retrospective study was conducted from 1996 to 2013. Individuals with (n = 26,069) and without (n = 26,069) MgO use were enroll...
Source: Osteoporosis International - Category: Orthopaedics Source Type: research
ConclusionWalking pGRF and pLR in normal weight to severely obese subjects can be predicted with moderate to high accuracy by accelerometry-based equations, representing an easy and accessible way to determine mechanical loading characteristics in clinical settings.
Source: Osteoporosis International - Category: Orthopaedics Source Type: research
In this study, there was no increased risk of adverse outcomes (including muscle aches, liver dysfunction, new onset of diabetes, cancer, and bleeding strokes), even when LDL was lowered to as low as 20 mg/dL. Although statin medications themselves have been linked to side effects, especially at high doses, it appears that extremely low LDL concentrations are not responsible for side effects. In other words, lowering LDL beyond our previous target of 70 mg/dL appears to be not only safe but beneficial, in patients with CVD. The post LDL cholesterol: How low can you (safely) go? appeared first on Harvard Health Blog.
Source: Harvard Health Blog - Category: Consumer Health News Authors: Tags: Drugs and Supplements Health Heart Health Source Type: blogs
Exp Clin Endocrinol Diabetes DOI: 10.1055/a-1084-3888The human urea transporter SLC14A1 (HUT11/UT-B) has been suggested as a marker for the adipogenic differentiation of bone cells with a relevance for bone diseases. We investigated the function of SLC14A1 in different cells models from bone environment. SLC14A1 expression and cytokine production was investigated in bone cells obtained from patients with osteoporosis. Gene and protein expression of SLC14A1 was studied during adipogenic or osteogenic differentiation of human mesenchymal progenitor cells (hMSCs) and of the single-cell–derived hMSC line (SCP-1), as well...
Source: Experimental and Clinical Endocrinology and Diabetes - Category: Endocrinology Authors: Tags: Article Source Type: research
Exp Clin Endocrinol Diabetes DOI: 10.1055/a-1088-1215Thyroid hormones are indispensable for bone development and growth. Also in adults, bone mass maintenance is under the control of thyroid hormones. Preclinical and clinical studies established untreated hyperthyroidism as a cause for secondary osteoporosis with increased fracture risk. Thus, normal thyroid function is essential for bone health. Mechanistically, thyroid hormone excess accelerates bone turnover with predominant bone resorption. How thyroid hormones affect osteoblast and osteoclast functions, however, still remains ill-defined. The Wnt signaling pathway is ...
Source: Experimental and Clinical Endocrinology and Diabetes - Category: Endocrinology Authors: Tags: Mini-Review Source Type: research
AbstractSummaryA reduction in hip fracture incidence following population screening might reflect the effectiveness of anti-osteoporosis therapy, behaviour change to reduce falls, or both. This post hoc analysis demonstrates that identifying high hip fracture risk by FRAX was not associated with any alteration in falls risk.IntroductionTo investigate whether effectiveness of an osteoporosis screening programme to reduce hip fractures was mediated by modification of falls risk in the screening arm.MethodsThe SCOOP study recruited 12,483 women aged 70 –85 years, individually randomised to a control (n =&thi...
Source: Osteoporosis International - Category: Orthopaedics Source Type: research
CONCLUSIONS: Findings suggest that bone-targeted exercise interventions for young adult women must address perceived time demands and environmental barriers to participation in order to maximise compliance and adherence. SO WHAT?: As physical activity is the most effective lifestyle strategy to improve bone health and young adulthood an important window for its augmentation, increasing convenience, accessibility and understanding of osteoporosis preventative behaviours in this demographic is vital. PMID: 31943497 [PubMed - as supplied by publisher]
Source: Health Promotion Journal of Australia - Category: International Medicine & Public Health Tags: Health Promot J Austr Source Type: research
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