Vitamin D deficiency amongst minority ethnic groups in the UK: a cross sectional study

Cross-sectional study of the associations between circulating vitamin D concentrations and insulin resistance in children aged 9-10 years of South Asian, black African Caribbean and white European origins

BACKGROUND

Lower circulating vitamin D 25-hydroxyvitamin D (25(OH)D) concentrations are associated with higher type 2 diabetes risk in adults, although causality remains uncertain. However, associations between 25(OH)D and type 2 diabetes risk markers in children have been little studied, particularly in ethnic minority populations. We examined whether 25(OH)D concentrations were associated with insulin resistance in children and whether lower 25(OH)D concentrations in South Asians and black African Caribbeans could contribute to their higher insulin resistance.

METHODS

Cross-sectional study of 4650 UK primary school children aged 9-10 years of predominantly South Asian, black African Caribbean and white European ethnicity. Children had fasting blood measurements of circulating 25(OH)D metabolite concentrations, insulin and glucose.

RESULTS

Lower 25(OH)D concentrations were observed in girls, South Asians and black African Caribbeans. In analyses adjusted for age, sex, month, ethnic group and school, circulating 25(OH)D was inversely associated with fasting insulin (-0.38%, 95% CI -0.49% to -0.27%), homoeostasis model assessment (HOMA) insulin resistance (-0.39%, 95% CI -0.50% to -0.28%) and fasting glucose (-0.03%, 95% CI -0.05% to -0.02%) per nmol/L increase in 25(OH)D; associations did not differ between ethnic groups. Ethnic differences in fasting insulin and HOMA insulin resistance (higher among South Asian and black African Caribbeans) were reduced by >40% after adjustment for circulating 25(OH)D concentrations.

CONCLUSION

Circulating vitamin D was inversely associated with insulin resistance in all ethnic groups; higher insulin resistance in South Asian and black African children were partly explained by their lower vitamin D levels. Whether vitamin D supplementation can reduce emerging type 2 diabetes risk needs further evaluation.

Global Perspective of the Vitamin D Status of African-Caribbean Populations: A Systematic Review and Meta-analysis

BACKGROUND/OBJECTIVES

Vitamin D deficiency remains a global public health issue, particularly in minority ethnic groups. This review investigates the vitamin D status (as measured by 25(OH)D and dietary intake) of the African-Caribbean population globally.

SUBJECTS/METHODS

A systematic review was conducted by searching key databases (PUBMED, Web of Science, Scopus) from inception until October 2019. Search terms included 'Vitamin D status' and 'African-Caribbean'. A random effects and fixed effects meta-analysis was performed by combining means and standard error of the mean.

RESULT

The search yielded 19 papers that included n = 5670 African-Caribbean participants from six countries. A meta-analysis found this population to have sufficient (>50 nmol/L) 25(OH)D levels at 67.8 nmol/L, 95% CI (57.9, 7.6) but poor dietary intake of vitamin D at only 3.0 µg/day, 95% CI (1.67,4.31). For those living at low latitudes 'insufficient' (as defined by study authors) 25(OH)D levels were found only in participants with type 2 diabetes and in those undergoing haemodialysis. Suboptimal dietary vitamin D intake (according to the UK recommended nutrient intake of 10 µg/day) was reported in all studies at high latitudes. Studies at lower latitudes, with lower recommended dietary intakes (Caribbean recommended dietary intake: 2.5 µg/day) found 'sufficient' intake in two out of three studies.

CONCLUSIONS

25(OH)D sufficiency was found in African-Caribbean populations at lower latitudes. However, at higher latitudes, 25(OH)D deficiency and low dietary vitamin D intake was prevalent.

Vitamin D Status of the British African-Caribbean Residents: Analysis of the UK Biobank Cohort

The vitamin D status of the United Kingdom (UK) African-Caribbean (AC) population remains under-researched, despite an increased risk of vitamin D deficiency due to darker skin phenotypes and living at a high latitude. This cross-sectional study explored the vitamin D status and intake of AC individuals (n = 4046 with a valid serum 25(OH)D measurement) from the UK Biobank Cohort, aged ≥40 years at baseline (2006-2010). Over one third of the population were deficient (<25 nmol/L), 41.1% were insufficient (25-50 nmol/L) and 15.9% were sufficient (>50 nmol/L). Median (IQR) 25(OH)D was 30.0 (20.9) nmol/L. Logistic regression showed that brown/black skin phenotype, winter blood draw, not consuming oily fish and not using vitamin D supplements predicted increased odds of vitamin D deficiency, whilst older age and a summer or autumn blood draw were significantly associated with reduced odds of vitamin D deficiency. Vitamin D deficiency and insufficiency were prevalent in this AC population and is of considerable concern given the individual and societal implications of increased morbidity. Public health messaging for this group should focus on year-round vitamin D supplementation and increasing intakes of culturally appropriate vitamin D-rich foods. These data also support the urgent requirement for a revised vitamin D RNI for ethnic groups.

Vitamin D deficiency in western dwelling South Asian populations: an unrecognised epidemic

Vitamin D deficiency (25-hydroxyvitamin D; 25(OH)D) is at epidemic proportions in western dwelling South Asian populations, including severe deficiency (<12⋅5 nmol/l) in 27-60% of individuals, depending on season. The paper aimed to review the literature concerning vitamin D concentrations in this population group. Research from the UK and Europe suggests a high prevalence of South Asians with 25(OH)D concentration <25 nmol/l, with most having a 25(OH)D concentration of <50 nmol/l. In Canada, South Asians appear to have a slightly higher 25(OH)D concentration. There are few studies from the United States, South Africa and Australasia. Reasons for vitamin D deficiency include low vitamin D intake, relatively high adiposity, sun exposure avoidance and wearing of a covered dress style for cultural reasons. Possible health effects of deficiency include bone diseases such as rickets and hypocalcaemia in children and osteomalacia in adults. Vitamin D deficiency may also increase the risk of other chronic diseases. Increased fortification of food items relevant to South Asian groups (e.g. chapatti flour), as well as increased use of vitamin D supplements may help reduce this epidemic. Introducing culturally acceptable ways of increasing skin exposure to the sun in South Asian women may also be beneficial but further research is needed to assess the effectiveness of different approaches. There may be a need for a South Asian specific vitamin D dietary intake guideline in western countries. To conclude, vitamin D deficiency is epidemic in South Asians living in western countries and there is a clear need for urgent public health action.

COVID-19 breakthroughs: separating fact from fiction

The newly recognised coronavirus SARS‐CoV‐2, causative agent of coronavirus disease (COVID‐19), has caused a pandemic with huge ramifications for human interactions around the globe. As expected, research efforts to understand the virus and curtail the disease are moving at a frantic pace alongside the spread of rumours, speculations and falsehoods. In this article, we aim to clarify the current scientific view behind several claims or controversies related to COVID‐19. Starting with the origin of the virus, we then discuss the effect of ibuprofen and nicotine on the severity of the disease. We highlight the knowledge on fomites and SARS‐CoV‐2 and discuss the evidence and explications for a disproportionately stronger impact of COVID‐19 on ethnic minorities, including a potential protective role for vitamin D. We further review what is known about the effects of SARS‐CoV‐2 infection in children, including their role in transmission of the disease, and conclude with the science on different mortality rates between different countries and whether this hints at the existence of more pathogenic cohorts of SARS‐CoV‐2.

COVID-19: Unique public health issues facing Black, Asian and minority ethnic communities

The 2019 coronavirus disease is a serious public health emergency, with serious adverse implications for populations, healthcare systems, and economies globally. Recently, concerns have been raised about possible association between ethnicity, incidence and outcomes of COVID-19 arisen from early government data. In this review, we will explore the possible association using both recent COVID-19 studies and studies of previous pandemics. We call for data on ethnicity to be routinely collected by governments, as part of an international collaboration, alongside other patient demographics and further research to robustly determine the magnitude of association. Moreover, governments must learn from previous pandemics and recommended strategies to mitigate risks on minority ethnicities due to socioeconomic disadvantages.

Genetic Contributions to Maternal and Neonatal Vitamin D Levels

Vitamin D is essential for several physiological functions and biological processes. Increasing levels of maternal vitamin D are required throughout pregnancy as a unique source of vitamin D for the fetus, and consequently maternal vitamin D deficiency may result in several adverse outcomes in newborns. However, the genetic regulation of vitamin D in pregnancy and at birth is not yet well understood. We performed genome-wide association studies of maternal midgestational serum-derived and neonatal blood-spot-derived total 25-hydroxyvitamin D from a case-control study of autism spectrum disorder (ASD). We identified one fetal locus (rs4588) significantly associated with neonatal vitamin D levels in the GC gene, encoding the binding protein for the transport and function of vitamin D. We also found suggestive cross-associated loci for neonatal and maternal vitamin D near immune genes, such as CXCL6-IL8 and ACKR1 We found no interactions with ASD. However, when including a set of cases with intellectual disability but not ASD (N = 179), we observed a suggestive interaction between decreased levels of neonatal vitamin D and a specific maternal genotype near the PKN2 gene. Our results suggest that genetic variation influences total vitamin D levels during pregnancy and at birth via proteins in the vitamin D pathway, but also potentially via distinct mechanisms involving loci with known roles in immune function that might be involved in vitamin D pathophysiology in pregnancy.

Vitamin D supplementation compared to placebo in people with First Episode psychosis - Neuroprotection Design (DFEND): a protocol for a randomised, double-blind, placebo-controlled, parallel-group trial

Background

People experiencing their first episode of psychosis are often deficient in vitamin D. Observational studies have reported an association between low vitamin D concentrations and poorer subsequent health outcomes in psychosis. A vitamin D deficiency in neonates and children has been linked to a later increased risk of schizophrenia and psychotic-like experiences. This trial aims to examine the effect of high-dose vitamin D supplementation on outcomes in early psychosis. We hypothesise that vitamin D supplementation will be associated with better mental health outcomes.

Methods/design

The DFEND study is a multicentre double-blind placebo-controlled parallel-group trial of vitamin D supplementation in people with early psychosis. Patients with an ICD-10 diagnosis of functional psychosis will be randomised in a 1:1 ratio to receive either 120,000 IU/month of vitamin D (cholecalciferol) or a matched placebo for 6 months. The primary outcome is the total Positive and Negative Syndrome Scale (PANSS) score at the 6-month follow-up for all patients. Secondary outcomes include assessment of mood (Calgary Depression Scale), general function (Global Assessment of Functioning), cardiovascular risk (body mass index, waist circumference, C-reactive protein, cholesterol and HbA1c) and vitamin D levels at the 6-month follow-up. Additionally, 3- and 6-month total PANSS scores will be analysed for those with inadequate vitamin D levels at the baseline.

Discussion

The DFEND study is the first trial to examine whether vitamin D supplementation in early psychosis is associated with better mental health outcomes. The findings of this study may help to resolve the clinical equipoise regarding the benefits and cost-effectiveness of routine vitamin D supplementation in people with psychosis.

Trial registration

ISRCTN, ISRCTN12424842. Registered on 25 February 2015.

The economic case for prevention of population vitamin D deficiency: a modelling study using data from England and Wales

BACKGROUND

Vitamin D deficiency (VDD) affects the health and wellbeing of millions worldwide. In high latitude countries such as the United Kingdom (UK), severe complications disproportionally affect ethnic minority groups.

OBJECTIVE

To develop a decision-analytic model to estimate the cost effectiveness of population strategies to prevent VDD.

METHODS

An individual-level simulation model was used to compare: (I) wheat flour fortification; (II) supplementation of at-risk groups; and (III) combined flour fortification and supplementation; with (IV) a 'no additional intervention' scenario, reflecting the current Vitamin D policy in the UK. We simulated the whole population over 90 years. Data from national nutrition surveys were used to estimate the risk of deficiency under the alternative scenarios. Costs incurred by the health care sector, the government, local authorities, and the general public were considered. Results were expressed as total cost and effect of each strategy, and as the cost per 'prevented case of VDD' and the 'cost per Quality Adjusted Life Year (QALY)'.

RESULTS

Wheat flour fortification was cost saving as its costs were more than offset by the cost savings from preventing VDD. The combination of supplementation and fortification was cost effective (£9.5 per QALY gained). The model estimated that wheat flour fortification alone would result in 25% fewer cases of VDD, while the combined strategy would reduce the number of cases by a further 8%.

CONCLUSION

There is a strong economic case for fortifying wheat flour with Vitamin D, alone or in combination with targeted vitamin D3 supplementation.

Micronutrient Deficiencies Are Common in Contemporary Celiac Disease Despite Lack of Overt Malabsorption Symptoms

OBJECTIVE

To evaluate micronutrient deficiencies in a contemporary cohort of adult patients with newly diagnosed celiac disease (CD).

PATIENTS AND METHODS

This is a retrospective study of prospective adults newly diagnosed with CD from January 1, 2000, through October 31, 2014, at Mayo Clinic. Micronutrient data were collected for tissue transglutaminase IgA, zinc, 25-hydroxy vitamin D, ferritin, albumin, copper, vitamin B₁₂, and serum folate. Data were analyzed for absolute number of deficiencies and associations with age, sex, body mass index, presenting symptoms, and tissue transglutaminase IgA; each deficiency was assessed using logistic regression. Deficiencies were compared with age- and sex-matched controls from the National Health and Nutrition Examination Survey.

RESULTS

In total, 309 patients with CD (196 women and 113 men; mean age, 46.1±15.1 years; mean body mass index, 25.9 kg/m²) were included. Weight loss was seen in only 25.2% (78/309) of patients. Zinc was deficient in 59.4% (126/212) of patients with CD compared with 33.2% (205/618) of controls (P<.001). Albumin was low in 19.7% (24/122) compared with 1.1% of controls (P<.001). Copper was low in 6.4% (13/204) compared with 2.1% (13/618) of controls (P=.003). Vitamin B₁₂ was low in 5.3% (13/244) compared with 1.8% (11/618) of controls (P=.004). Folate was low in 3.6% (6/159) compared with 0.3% (2/618) of controls (P=.002). 25-Hydroxy vitamin D was low in 19.0% (44/213) compared with 18% (111/618) of controls (P=.72). Ferritin was low in 30.8% (66/214) of patients; no NHANES controls were available for comparison for ferritin.

CONCLUSION

Micronutrient deficiencies remain common in adults with CD despite increased nonclassic presentation. This study provides support for micronutrient assessment at the time of CD diagnosis.

Associations of maternal vitamin D, PTH and calcium with hypertensive disorders of pregnancy and associated adverse perinatal outcomes: Findings from the Born in Bradford cohort study

Vitamin D and parathyroid hormone (PTH) regulate mineral metabolism and are required to maintain calcium levels. Vitamin D deficiency is common, particularly during pregnancy, and has been associated with hypertensive disorders of pregnancy. We sought to determine whether maternal 25(OH)D, PTH and calcium concentrations at 26 weeks gestation are associated with adverse outcomes of pregnancy and establish whether these differ by ethnicity. This study included 476 White British and 534 Pakistani origin mother-offspring pairs from the Born in Bradford cohort study. We used multinomial or logistic regression to explore the association between vitamin D, PTH and calcium with gestational hypertension (GH), pre-eclampsia (PE), caesarean section (CS), preterm birth (PTB) and small for gestational age (SGA). Pakistani women had lower 25(OH)D (median 13.0 vs 36.0 nmol/L), higher PTH (median 7.7 vs 3.3 pmol/L) and similar calcium concentrations compared to White British women. In Pakistani women, higher concentrations of 25(OH)D were associated with a 60% increased odds of GH, and a 37% reduced odds of SGA; PTH was associated with a 45% reduction in the odds of GH. In White British women, each 1 SD increase in calcium concentration was associated with a 34% increase in developing GH but a 33% reduction in the odds of PTB. Associations with PE and CS were consistent with the null. In conclusion, there are ethnic differences in the associations of 25(OH)D, PTH and calcium with important perinatal outcomes. Future research would benefit from examining the associations of 25(OH)D, PTH and calcium together with a range of perinatal outcomes in order to assess the risk-benefit action of each.

Vitamin D status by sociodemographic factors and body mass index in Mexican women at reproductive age

OBJECTIVE

To describe the prevalence of Vitamin D deficiency (VDD) and insufficiency (VDI), and the main dietary sources of vitamin D (VD) in a probabilistic sample of Mexican women at reproductive age participating in Ensanut 2012, stratified by sociodemographic factors and body mass index (BMI) categories.

MATERIALS AND METHODS

Serum concentrations of 25-hydroxyvitamin-D(25-OH-D) were determined using an ELISA technique in 4162 women participants of Ensanut 2012 and classified as VDD, VDI or optimal VD status. Sociodemographic, anthropometric and dietary data were also collected. The association between VDD/VDI and sociodemographic and anthropometry factors was assessed adjusting for potential confounders through an estimation of a multinomial logistic regression model.

RESULTS

The prevalence of VDD was 36.8%, and that of VDI was 49.8%. The mean dietary intake of VD was 2.56 μg/d. The relative risk ratio (RRR) of VDD or VDI was calculated by a multinomial logistic regression model in 4162 women. The RRR of VDD or VDI were significantly higher in women with overweight (RRR: 1.85 and 1.44, p<0.05), obesity (RRR: 2.94 and 1.93, p<0.001), urban dwelling (RRR:1.68 and 1.31, p<0.06), belonging to the 3rd tertile of income (RRR: 5.32 and 2.22, p<0.001), or of indigenous ethnicity (RRR: 2.86 and 1.70, p<0.05), respectively.

CONCLUSION

The high prevalence of VDD/VDI in Mexican women calls for stronger actions from the health authorities, strengthtening the actual policy of food supplementation and recommending a reasonable amount of sun exposure.

Vitamin D Status among Young Children Aged 6 to 23 Months from 4 Different Ethnic Groups in Yunnan, China

OBJECTIVES

To determine the prevalence of vitamin D deficiency in 6- to 23-month-old children from 4 different ethnic groups, Han, Lisu, Hani, and Bai, in Yunnan Province of China.

METHODS

A large cohort of 938 young children aged 6 to 23 months who were living in Yunnan, China (23°28'-27°52' N), were selected and recruited in this study. Venous-blood sampling was conducted in all the participants, and serum 25-hydroxyvitamin D [25(OH)D] levels were measured. The children's physical status was measured.

RESULTS

General mean serum 25(OH)D level was 21.46 ± 7.95 ng/mL, which was obtained from a total of 938 cases. No significant difference was found in age, gender, height, and weight of participants from different ethnic groups. The mean 25(OH)D level was significantly lower in children of Lisu ethnic groups compared with that of Han and Hani participants, respectively ( P < .05). In addition, Bai children had lower 25(OH)D content than Hani children ( P < .001). Among the children with 25(OH)D sufficiency, the number of Lisu participants was significantly lower than Han children ( P < .001).

CONCLUSION

The prevalence of vitamin D deficiency varied among the ethnically different children in Yunnan, China, and significantly fewer Lisu children maintained vitamin D sufficiency compared with other ethnic children. Recognizing these ethnic differences in treating children with vitamin D deficiency may improve the therapeutic outcome.

Vitamin D and Ageing

One hundred years has passed since the discovery of vitamin D as the active component of cod-liver oil which cured the bone disease rickets. Since then our knowledge of vitamin D has expanded tremendously and has included recognition of the importance of UV radiation as a source of the vitamin as well as the discovery of the vitamin as a nutrient, a pro-hormone and a potent steroid hormone with a major role in calcium and bone metabolism. In the last 25 years or so, the discovery of the vitamin D receptor in over 30 different body tissues together with the existence of the alpha-1-hydroxylase enzyme in these tissues provided evidence of a pleiotropic role of vitamin D outside its classical role in the skeleton. These important discoveries have provided the basis for the increasing interest in vitamin D in the context of nutritional requirements for health including the prevention of chronic diseases of ageing. The recent publication of the Dietary Reference Intake report on vitamin D and calcium by the North American Institute of Medicine (IOM) is the most comprehensive report to date on the basis for setting nutritional requirements for vitamin D. This chapter will summarize the nutritional aspects of vitamin D and discuss the changes in vitamin D metabolism and requirements with ageing. It will summarize key evidence on the relationship between vitamin D status and some of the main ageing related health outcomes including bone, muscle and cognitive health as well as survival focusing on the published literature in very-old adults (those >= 85 years of age).

Special considerations for vitamin D in the south Asian population in the UK

The human requirement for vitamin D is achieved primarily through the synthesis of this prehormone in the skin during exposure to ultraviolet B (UVB) radiation, with only a minor contribution from the diet, year round. Achieving optimal vitamin D status is therefore largely dependent upon adequate exposure of the skin to sunlight, however, the length of exposure required varies with latitude and season, and is also dependent upon skin pigmentation, with darker skin requiring greater exposure than fair skin due to the protective effects of melanin against UVB radiation. In northern European latitudes, where UVB radiation between the months of October and March is of insufficient intensity for the synthesis of vitamin D via this route, vitamin D deficiency is a public health concern, particularly for south Asian diaspora and other dark-skinned ethnic minority communities. The consequences of vitamin D deficiency include poor bone health, including rickets and osteomalacia. In addition, there is increasing awareness of an important role for vitamin D in the development and progression of chronic diseases, including type 2 diabetes, which is prevalent in south Asian populations. The aim of this review is to examine some of the most recent reports of vitamin D status in south Asian diaspora communities, and to explore its impact on bone health. In addition, we will examine the putative association between type 2 diabetes and vitamin D deficiency in south Asian populations and the current guidelines for treatment of vitamin D deficiency of south Asians in primary care settings.

Assessment of bone mineral density in tenofovir-treated patients with chronic hepatitis B: can the fracture risk assessment tool identify those at greatest risk?

BACKGROUND

Tenofovir disoproxil fumarate (TDF) is an established nucleotide analogue in the treatment of chronic hepatitis B. Bone mineral density loss has been described in TDF-treated patients with human immunodeficiency virus infection, but limited data exist for patients with chronic hepatitis B. Dual X-ray absorptiometry (DEXA) was used to determine bone mineral density changes in TDF-exposed patients. We evaluated the accuracy of the Fracture Risk Assessment Tool (FRAX) as an alternative to DEXA in clinical practice.

METHODS

A total of 170 patients were studied: 122 were exposed to TDF, and 48 were controls. All patients underwent DEXA, and demographic details were recorded. FRAX scores (before and after DEXA) were calculated.

RESULTS

TDF was associated with a lower hip T score (P = .02). On univariate and multivariate analysis, advancing age, smoking, lower body mass index, and TDF exposure were independent predictors of low bone mineral density. In addition, the pre-DEXA FRAX score was an accurate predictor of the post-DEXA FRAX treatment recommendation (100% sensitivity and 83% specificity), area under the curve 0.93 (95% CI, .87-.97, P < .001).

CONCLUSIONS

TDF-treated patients with chronic hepatitis B have reduced bone mineral density, but the reduction is limited to 1 anatomical site. Age and advanced liver disease are additional contributing factors, underlining the importance of multifactorial fracture risk assessment. FRAX can accurately identify those at greatest risk of osteoporotic fracture.

Associations of circulating calcium and 25-hydroxyvitamin D with glucose metabolism in pregnancy: a cross-sectional study in European and South Asian women

BACKGROUND

Vitamin D deficiency is thought to impair insulin action and glucose metabolism; however, previous studies have not examined ethnic differences or the influence of calcium and parathyroid hormone. We investigated this in a cohort of predominantly white European and south Asian women during pregnancy.

METHODS

In this cross-sectional study from an urban population in northern England (53.8°N), 1467 women were recruited when undergoing glucose tolerance testing (75 g oral glucose tolerance test) at 26 weeks' gestation.

RESULTS

Gestational diabetes mellitus (GDM) was diagnosed in 137 women (9.3%). Median 25-hydroxyvitamin D concentration for the study population was 9.3 ng/mL (interquartile range 5.2, 16.9) and was higher in European [15.2 ng/mL (10.7, 23.5)] than in south Asian women [5.9 ng/mL (3.9, 9.4), P < .001]. After appropriate adjustment for confounders, 25-hydroxyvitamin D showed a weak inverse association with fasting plasma glucose (FPG; mean difference 1.0% per 1 SD; the ratio of geometric means (RGM) 0.99, 95% confidence interval (CI) 0.98, 1.00), and PTH was weakly associated with FPG (RGM 1.01, 95% CI 1.00, 1.02), but neither was associated with fasting insulin, postchallenge glucose, or GDM. Serum calcium (albumin adjusted) was strongly associated with fasting insulin (RGM 1.06; 95% CI 1.03, 1.08), postchallenge glucose (RGM 1.03, 95% CI 1.01, 1.04), and GDM (odds ratio 1.33, 95% CI 1.06, 1.66) but not with FPG. Associations were similar in European and south Asian women.

CONCLUSIONS

These findings do not indicate any important association between vitamin D status and glucose tolerance in pregnancy. Relationships between circulating calcium and glucose metabolism warrant further investigation.

Vitamin D and bone health outcomes in older age

The aim of this review is to summarise the evidence linking vitamin D to bone health outcomes in older adults. A plethora of scientific evidence globally suggests that large proportions of people have vitamin D deficiency and are not meeting recommended intakes. Older adults are at particular risk of the consequences of vitamin D deficiency owing to a combination of physiological and behavioural factors. Epidemiological studies show that low vitamin D status is associated with a variety of negative skeletal consequences in older adults including osteomalacia, reduced bone mineral density, impaired Ca absorption and secondary hyperparathyroidism. There seems to be inconsistent evidence for a protective role of vitamin D supplementation alone on bone mass. However, it is generally accepted that vitamin D (17·5 μg/d) in combination with Ca (1200 mg/d) reduces bone loss among older white subjects. Evidence for a benefit of vitamin D supplementation alone on reducing fracture risk is varied. According to a recent Agency for Healthcare Research and Quality review in the USA the evidence base shows mixed results for a beneficial effect of vitamin D on decreasing overall fracture risk. Limitations such as poor compliance with treatment, incomplete assessment of vitamin D status and large drop-out rates however, have been highlighted within some studies. In conclusion, it is generally accepted that vitamin D in combination with Ca reduces the risk of non-vertebral fractures particularly those in institutional care. The lack of data on vitamin D and bone health outcomes in certain population groups such as diverse racial groups warrants attention.