Clinical medicine (London, England)
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    Over recent decades, the perception of osteoporosis has changed from that of an inevitable consequence of ageing, to that of a well characterised and treatable chronic non-communicable disease, with major impacts on individuals, healthcare systems and societies. Characterisation of its pathophysiology from the hierarchical structure of bone and the role of its cell population, development of effective strategies for the identification of those most appropriate for treatment, and an increasing armamentarium of efficacious pharmacological therapies, have underpinned this evolution. Despite this marked progress, individuals who experience a fragility fracture remain under-treated in many areas of the world, and there is substantial need for investment both in secondary and primary prevention globally. In this brief article, we give an overview of the pathogenesis of osteoporosis, and summarise current and future approaches to its assessment and treatment. 
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    Alcoholic liver disease (ALD) and, increasingly, non-alcoholic fatty liver disease (NAFLD) are common causes of advanced liver disease in many developed countries including the UK. Both diseases share parallel natural histories, progressing from steatosis, to steatohepatitis and fibrosis/cirrhosis; and are characterised by substantial interindividual variation in disease outcome. This article will provide an overview of disease mechanisms, genetic modifiers and management, focusing principally on NAFLD, while drawing parallels between the two conditions where appropriate. 
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    Polycystic ovary syndrome (PCOS) is a common condition that typically develops in reproductive-age women. The cardinal clinical and biochemical characteristics of PCOS include reproductive dysfunction and hyperandrogenic features. PCOS is also strongly associated with obesity based on data from epidemiological and genetic studies. ⋯ Future developments of novel therapies for obese women with PCOS should focus on promotion of weight loss and improvement in insulin sensitivity. In this context, therapies that complement lifestyle changes such as dietary modification and exercise, particularly during the maintenance phase of weight loss are important. Putative novel targets for therapy in PCOS include human brown adipose tissue. 
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    Systemic sclerosis is the most severe disease within the scleroderma spectrum and is a major medical challenge with high mortality and morbidity. There have been advances in understanding of pathogenesis that reflect the interplay between immune-inflammatory processes and vasculopathy and fibrosis. ⋯ Treatment is available for many aspects of the disease although the available therapies are not curative and some complications remain very challenging, especially non-lethal manifestations such as fatigue, calcinosis and anorectal dysfunction. Immunosuppression is now established as a beneficial approach but balancing risk and benefit is vital, especially for powerful approaches such as autologous stem cell transplantation. 
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    Vitamin D deficiency is a public health concern. Mediated by classical endocrine effects, vitamin D deficiency is causally linked with bone and calcium disorders. ⋯ Supported by large volumes of observational studies linking low circulating vitamin D with negative outcomes for many common disease states, there is growing interest that vitamin D may be central to the pathology and outcomes of many common diseases, including cardiovascular, cancer and autoimmune conditions. This article explores the quality of evidence linking vitamin D and various disease outcomes, and furthermore describes some of the cellular and molecular mechanisms of vitamin D action that may help explain some of the incongruity of data observed in observational versus interventional studies of vitamin D supplementation.