Diagnosis and management of vitamin D deficiency

Abstract

For the full versions of these articles see bmj.comRickets in children and osteomalacia in adults are the classic manifestations of profound vitamin D deficiency. In recent years, however, non-musculoskeletal conditions-including cancer, metabolic syndrome, infectious and autoimmune disorders-have also been found to be associated with low vitamin D levels. 1 The spectrum of these common disorders is of particular concern because observational studies have demonstrated that vitamin D insufficiency is widespread in many northern regions of the world, including industrialised countries. 2 3 The increasing prevalence of disorders linked to vitamin D deficiency is reflected in the several hundred children with rickets treated each year in the UK. 4 However, these children represent a small proportion of the individuals with a suboptimal vitamin D status in the UK population. 1 3 5 A recent nationwide survey in the United Kingdom showed that more than 50% of the adult population have insufficient levels of vitamin D and that 16% have severe deficiency during winter and spring. 5 The survey also demonstrated a gradient of prevalence across the UK, with highest rates in Scotland, northern England, and Northern Ireland. 5 People with pigmented skin are at high risk, as are the elderly; obese individuals; those with malabsorption, short bowel, or renal or liver disease; and individuals t aking anticonvulsants, rifampicin, or highly active anti retroviral drugs.In this article we discuss the diagnosis and management of vitamin D insufficiency and deficiency in children and adults according to evidence from descriptive and observational studies, randomised trials, and metaanalyses. what are the sources of vitamin D?Vitamin D refers to the precursors of the active secosteroid hormone 1,25-dihydroxyvitamin D 3 (1,25-OH 2 D 3 ), also known as calcitriol. The major natural source of vitamin D is from skin photosynthesis following ultraviolet B solar irradiation (box 1).In a fair skinned person, 20 minutes to 30 minutes of sunlight exposure on the face and forearms at midday is estimated to generate the equivalent of around 2000 IU of vitamin D. Two or three such sunlight exposures a week are sufficient to achieve healthy vitamin D levels in summer Vitamin D insufficiency is common in the UK population Vitamin D deficiency typically presents with bony deformity (rickets) or hypocalcaemia in infancy and childhood, and with musculoskeletal pain and weakness in adults Many other health problems-including cardiovascular disease, type 2 diabetes, several cancers, and autoimmune conditions-have recently been associated with vitamin D insufficiency Risk factors include skin pigmentation, use of sunscreen or concealing clothing, being elderly or institutionalised, obesity, malabsorption, renal and liver disease, and anticonvulsant use Vitamin D status is most reliably determined by assay of serum 25-hydroxyvitamin D (25-OHD) Rickets and osteomalacia should be treated with high strength calciferol (ergocalciferol or colecalciferol) for 8-...

Vitamin D and risk of CVD: a review of the evidence

“…Migrants with darker skin moving to northern latitudes are particularly at risk of developing vitamin D deficiency (19) . The use of a sunscreen or clothing/ headscarves which cover the skin can also reduce skin synthesis of vitamin D (20)(21)(22) . Older age may lead to a decrease in 25(OH)D concentrations as ageing has been shown to be associated with decreased concentrations of 7-dehydrocholesterol in the skin (21) and older people may be less likely to spend time outdoors, particularly if they are institutionalised.…”

Oral vitamin D supplementation has a lower bioavailability and reduces hypersecretion of parathyroid hormone and insulin resistance in obese Chinese males

“…Since vitamin D nutritional status may be important in regulating obesity (3)(4)(5)(6) , interest was aroused to study Chinese obese males in this regard. Circulating 25-hydroxyvitamin D (25(OH)D; calcidiol), a metabolite of vitamin D having a half-life of 2-3 weeks, is recommended as a reliable marker of vitamin D nutritional status (7)(8)(9)(10) . The US Institute of Medicine (11) reports that a circulating 25(OH)D concentration equal to 50 nmol/l (20 ng/ml) meets the vitamin D requirements of 97·5 % of the population, and this threshold is widely accepted for hypovitaminosis D (10,(12)(13)(14) .…”

Association Between Low Serum 25-Hydroxyvitamin D and Depression in a Large Sample of Healthy Adults: The Cooper Center Longitudinal Study

“…3,4 More recently, low vitamin D level has also been associated with neurologic disorders such as multiple sclerosis, Alzheimer disease, Parkinson disease, and cognitive decline. [3][4][5][6][7] Vitamin D receptors and the vitamin D-activating enzyme 1α−hydroxylase are found in most organ systems of the human body, including the brain. 8 Within the hypothalamus and the dopaminergic neurons of the substantia nigra is found a high density of vitamin D receptors as well as the vitamin D-activating enzyme.…”

“…3,4 More recently, low vitamin D level has also been associated with neurologic disorders such as multiple sclerosis, Alzheimer disease, Parkinson disease, and cognitive decline. [3][4][5][6][7] Vitamin D receptors and the vitamin D-activating enzyme 1α−hydroxylase are found in most organ systems of the human body, including the brain.…”