Vitamin D, obesity, and obesity-related chronic disease among ethnic minorities : a systematic review

Objective : To assess the association between 25-hydroxyvitamin D (25[OH]D) status and obesity, cardiovascular diseases (CVDs), the metabolic syndrome, and type 2 diabetes mellitus (T2DM) in ethnic minorities.

Methods : Databases searched were CINHAL with full text, Global Health, MEDLINE with full text, and PsycINFO from 1980 through 2010 (February). Studies were included if they 1) targeted immigrants from low- to high-income countries or ethnic minorities, 2) focused primarily on 25(OH)D and its relation to obesity, T2DM, and/or CVDs, and 3) were published in peer-reviewed journals. The influences of key confounders such as age, gender, and ethnicity on any observed relations were also assessed. Due to the heterogeneity of study characteristics, only a narrative synthesis was undertaken.

Results : Ethnic minorities had significantly higher rates of vitamin D insufficiency (25[OH]D <50 nmol/L; children 43.6&ndash;48.7% versus 10%; adults 30.3&ndash;53% versus 13.7&ndash;26%) than their white counterparts. None of the studies reported a prevalence of obesity stratified by ethnicity. There was evidence supporting links between vitamin D deficiency and obesity-related chronic diseases, with 14 of 14 studies reporting a statistically significant result with a measurement of obesity, four of five for T2DM, four of five for CVDs, and one of one for the metabolic syndrome. However, the strength of the association varied across ethnic groups depending on the index used to measure adiposity, T2DM, and CVDs. Because most of the included studies were cross-sectional and there were variations in outcome measurements, it was not possible to determine the relative contributions of obesity or vitamin D insufficiency to CVD risk and risk of T2DM or which is the initial driver It is possible both have a role to play.

Conclusion : Further research specific to migrant populations using randomized controlled trials are required to establish whether causal links between 25(OH)D and obesity-related chronic disease exist, and whether vitamin D supplementation could be valuable in the prevention or treatment of obesity-related diseases.

Vitamin D and adult bone health in Australia and New Zealand : a position statement

• A significant number of Australians are deficient in vitamin D - it is a fallacy that Australians receive adequate vitamin D from casual exposure to sunlight.

• People at high risk of vitamin D deficiency include elderly people (particularly those in residential care), people with skin conditions where avoidance of sunlight is advised, those with dark skin (particularly if veiled), and those with malabsorption.

• Exposure of hands, face and arms to one-third of a minimal erythemal dose (MED) of sunlight (the amount that produces a faint redness of skin) most days is recommended for adequate endogenous vitamin D synthesis. However, deliberate sun exposure between 10:00 and 14:00 in summer (11:00-15:00 daylight saving time) is not advised.

• If this sun exposure is not possible, then a vitamin D supplement of at least 400IU (10 μg) per day is recommended.

• In vitamin D deficiency, supplementation with 3000-5000 IU ergocalciferol per day (Ostelin [Boots]; 3-5 capsules per day) for 6-12 weeks is recommended.

• Larger-dose preparations of ergocalciferol or cholecalciferol are available in New Zealand, Asia and the United States and would be useful in Australia to treat moderate to severe vitamin D deficiency states in the elderly and those with poor absorption; one or two annual intramuscular doses of 300 000 IU of cholecalciferol have been shown to reverse vitamin D deficiency states.

Maternal 25-Hydroxyvitamin D and parathyroid hormone concentrations and offspring birth size

Context: There is inconsistent evidence that maternal 25-hydroxyvitamin D [25-(OH)D] deficiency may impair fetal growth.

Objective: The objective of the study was to examine the relationship between maternal 25-(OH)D and PTH concentrations at less than 16 and 28 wk gestation and offspring birth size.

Design: This was an observational study.

Setting: The study was set at a hospital antenatal clinic.

Participants: Women with singleton pregnancies, before 16 wk gestation, participated.

Interventions: No interventions were used.

Main Outcome Measure: Knee-heel length at birth was the main outcome measure.

Results: Altogether 374 of 475 (79%) women completed this study. We found no evident relationship between birth size measures and maternal 25-(OH)D or PTH at recruitment (∼11 wk). Gestation length was 0.7 wk (95% confidence interval −1.3, −0.1) shorter and knee-heel length was 4.3 mm smaller (−7.3, −1.3) in infants of 27 mothers with low 25-(OH)D (<28 nmol/liter) at 28&ndash;32 wk vs. babies whose mothers had higher concentrations. This latter difference was reduced to −2.7 mm (−5.4, −0.1) after adjustment for gestation length, suggesting some of the apparent growth deficit is explained by shorter gestation. There was no evidence that other birth measures were affected. Maternal PTH concentration at 28&ndash;32 wk was positively related to knee-heel length, birth weight, and mid-upper arm and calf circumferences. These associations were independent of 25-(OH)D concentration.

Conclusions: Low maternal 25-(OH)D in late pregnancy is associated with reduced intrauterine long bone growth and slightly shorter gestation. The long-term consequences for linear growth and health require follow-up. The positive relationship between maternal PTH and measures of infant size may relate to increased mineral demands by larger babies, but warrants further investigation.

Vitamin D and health in adults in Australia and New Zealand : a position statement

The prevalence of vitamin D deficiency varies, with the groups at greatest risk including housebound, community-dwelling older and/or disabled people, those in residential care, dark-skinned people (particularly those modestly dressed), and other people who regularly avoid sun exposure or work indoors.

Most adults are unlikely to obtain more than 5%&ndash;10% of their vitamin D requirement from dietary sources. The main source of vitamin D for people residing in Australia and New Zealand is exposure to sunlight.

A serum 25-hydroxyvitamin D (25-OHD) level of ≥ 50 nmol/L at the end of winter (10&ndash;20 nmol/L higher at the end of summer, to allow for seasonal decrease) is required for optimal musculoskeletal health.

Although it is likely that higher serum 25-OHD levels play a role in the prevention of some disease states, there is insufficient evidence from randomised controlled trials to recommend higher targets.

For moderately fair-skinned people, a walk with arms exposed for 6&ndash;7 minutes mid morning or mid afternoon in summer, and with as much bare skin exposed as feasible for 7&ndash;40 minutes (depending on latitude) at noon in winter, on most days, is likely to be helpful in maintaining adequate vitamin D levels in the body.

When sun exposure is minimal, vitamin D intake from dietary sources and supplementation of at least 600 IU (15 μg) per day for people aged ≤ 70 years and 800 IU (20 μg) per day for those aged > 70 years is recommended. People in high-risk groups may require higher doses.

There is good evidence that vitamin D plus calcium supplementation effectively reduces fractures and falls in older men and women.

Low serum 25-hydroxyvitamin D is associated with increased risk of the development of the metabolic syndrome at five years : results from a national, population-based prospective study (the Australian Diabetes, Obesity and Lifestyle Study : AusDiab)

Context: Serum 25-hydroxyvitamin D [25(OH)D] concentration has been inversely associated with the prevalence of metabolic syndrome (MetS), but the relationship between 25(OH)D and incident MetS remains unclear.

Objective: We evaluated the prospective association between 25(OH)D, MetS, and its components in a large population-based cohort of adults aged 25 yr or older.

Design: We used baseline (1999&ndash;2000) and 5-yr follow-up data of the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab).

Participants: Of the 11,247 adults evaluated at baseline, 6,537 returned for follow-up. We studied those without MetS at baseline and with complete data (n = 4164; mean age 50 yr; 58% women; 92% Europids).

Outcome Measures: We report the associations between baseline 25(OH)D and 5-yr MetS incidence and its components, adjusted for age, sex, ethnicity, season, latitude, smoking, family history of type 2 diabetes, physical activity, education, kidney function, waist circumference (WC), and baseline MetS components.

Results: A total of 528 incident cases (12.7%) of MetS developed over 5 yr. Compared with those in the highest quintile of 25(OH)D (≥34 ng/ml), MetS risk was significantly higher in people with 25(OH)D in the first (<18 ng/ml) and second (18&ndash;23 ng/ml) quintiles; odds ratio (95% confidence interval) = 1.41 (1.02&ndash;1.95) and 1.74 (1.28&ndash;2.37), respectively. Serum 25(OH)D was inversely associated with 5-yr WC (P < 0.001), triglycerides (P < 0.01), fasting glucose (P < 0.01), and homeostasis model assessment for insulin resistance (P < 0.001) but not with 2-h plasma glucose (P = 0.29), high-density lipoprotein cholesterol (P = 0.70), or blood pressure (P = 0.46).

Conclusions: In Australian adults, lower 25(OH)D concentrations were associated with increased MetS risk and higher WC, serum triglyceride, fasting glucose, and insulin resistance at 5 yr. Vitamin D supplementation studies are required to establish whether the link between vitamin D deficiency and MetS is causal.

Vitamin D and the musculoskeletal health of older adults

The scientific literature related to vitamin D and bone health in older adults is extensive.

This article aims to summarise key practice points regarding vitamin D and bone health in older adults, relevant to general practitioners, and to provide an overview of the background literature to enable GPs to appreciate the extent of the supporting evidence.

Vitamin D supplementation can prevent falls, particularly in the vitamin D deficient elderly. However, adequate vitamin D levels and dietary calcium intake are needed for effective primary fracture prevention with greatest benefits occurring in the elderly with vitamin D deficiency and/or low dietary calcium intakes. For secondary fracture prevention, ie. preventing further fractures in the elderly who have already sustained a fragility fracture, specific anti-osteoporosis treatment is necessary. However, to maximise the benefits of these medications, vitamin D deficiency should be corrected and adequate dietary calcium consumed.

Vitamin D and health in pregnancy, infants, children and adolescents in Australia and New Zealand: a position statement.

The recommended level for serum 25-hydroxyvitamin D (25(OH)D) in infants,  children,  dolescents and during pregnancy and lactation is ≥ 50 nmol/L. This level may need to be 10-20 nmol/L higher at the end of summer to maintain levels ≥ 50 nmol/L over winter and spring. • Sunlight is the most important source of vitamin D. The US recommended dietary allowance for vitamin D is 600 IU daily in children aged over 12 months and during pregnancy and lactation, assuming minimal sun exposure. • Risk factors for low vitamin D are: lack of skin exposure to sunlight, dark skin, southerly latitude, conditions affecting vitamin D metabolism and storage (including obesity) and, for infants, being born to a mother with low vitamin D and exclusive breastfeeding combined with at least one other risk factor. • Targeted measurement of 25(OH)D levels is recommended for infants, children and adolescents with at least one risk factor for low vitamin D and for pregnant women with at least one risk factor for low vitamin D at the first antenatal visit. • Vitamin D deficiency can be treated with daily low-dose vitamin D supplements, although barriers to adherence have been identified. High-dose intermittent vitamin D can be used in children and adolescents. Treatment should be paired with health education and advice about sensible sun exposure. Infants at risk of low vitamin D should be supplemented with 400 IU vitamin D₃ daily for at least the first year of life. • There is increasing evidence of an association between low vitamin D and a range of non-bone health outcomes, however there is a lack of data from robust randomised controlled trials of vitamin D supplementation.

Are vitamins A and D important in the development of food allergy and how are they best measured?

Food allergy has a dramatic impact on a child's (and their family's) quality of life and places a major financial burden on the community. It has been hypothesized that the increase in food allergy may relate to the concordant rise in prevalence of vitamin D insufficiency. More recently a second hypothesis has implicated vitamin A sufficiency in the development of immune tolerance. Together, these hypotheses have prompted investigation into the circulating levels of vitamins A and D in relation to food allergy prevalence. This review aims to examine the relationship between vitamins A and D and food allergy. The first part of this review presents the available epidemiological data which proposes a dramatic increase of food allergy and related anaphylaxis during the last two decades. There is some indirect evidence that variation in food allergy prevalence within countries might be linked with ambient ultra violet radiation exposure and thus potentially with vitamin D levels. Only a few studies to date have directly examined the relationship between measured serum vitamin D levels and either food sensitization or allergy. The significance of vitamin A in food allergy prevalence is only provided through a hypothetical association due to its role in the immune system. The second part of this review discusses the relevant aspects of the analytical methods to assess vitamin A and D levels in children. The primary methods utilized relate to measuring the main circulating forms of vitamins A and D in blood i.e. retinol and 25-hydroxy-vitamin-D3 respectively. Chromatographic separation coupled with mass spectrometric detection is considered the gold standard method for both vitamins. These analytical methods should be fully validated for the use in pediatric populations to ensure they are fit for their clinical purpose.

Environmental and genetic determinants of vitamin D insufficiency in 12-month-old infants

We aimed to investigate the relationship between genetic and environmental exposure and vitamin D status at age one, stratified by ethnicity. This study included 563 12-month-old infants in the HealthNuts population-based study. DNA from participants' blood samples was genotyped using Sequenom MassARRAY MALDI-TOF system on 28 single nucleotide polymorphisms (SNPs) in six genes. Using logistic regression, we examined associations between environmental exposure and SNPs in vitamin D pathway and filaggrin genes and vitamin D insufficiency (VDI). VDI, defined as serum 25-hydroxyvitamin D3(25(OH)D3) level ≤50 nmol/L, was measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Infants were stratified by ethnicity determined by parent's country of birth. Infants formula fed at 12 months were associated with reduced odds of VDI compared to infants with no current formula use at 12 months. This association differed by ethnicity (P;bsubesub;= 0.01). The odds ratio (OR) of VDI was 0.29 for Caucasian infants (95% CI, 0.18-0.47) and 0.04 for Asian infants (95% CI, 0.006-0.23). Maternal vitamin D supplementation during pregnancy and/or breastfeeding were associated with increased odds of infants being VDI (OR, 2.39; 95% CI, 1.11-5.18 and OR, 2.5; 95% CI, 1.20-5.24 respectively). Presence of a minor allele for any GC SNP (rs17467825, rs1155563, rs2282679, rs3755967, rs4588, rs7041) was associated with increased odds of VDI. Caucasian infants homozygous (AA) for rs4588 had an OR of 2.49 of being associated with VDI (95% CI, 1.19-5.18). In a country without routine infant vitamin D supplementation or food chain fortification, formula use is strongly associated with a reduced risk of VDI regardless of ethnicity. There was borderline significance for an association between filaggrin mutations and VDI. However, polymorphisms in vitamin D pathway related genes were associated with increased likelihood of being VDI in infancy. © 2014 Elsevier B.V. All rights reserved.

Patients presenting with fractures are likely to be vitamin D deficient: are we getting enough sun?

BACKGROUND: 25-Hydroxyvitamin D serves a crucial role in bone metabolism through its role on osteoclast and osteoblastic function. To assess the implication of vitamin D and its relationship to bone fracture and fracture force, we have examined vitamin D levels in patients requiring inpatient fracture management. METHODS: We performed serological testing of vitamin D levels, calcium, parathyroid hormone and liver function tests on patients admitted to our rural institution in southeastern Australia for inpatient fracture management. All participants completed a questionnaire designed to screen for potential contributing factors to bony fragility. Demographic data were also obtained including age, gender and body mass index. Fracture location and the type of inpatient management as well as the force of injury were included in our analysis. RESULTS: We recruited 100 patients to the study, with a median age of 72 (range 22-98) of whom 66 were women. Most had low-energy fractures (79%), treated by internal fixation (73%) or arthroplasty (9%) with 18 treated non-operatively. The majority of the patients were at best vitamin D insufficient, <75 nmol/L (77%), and 38% were vitamin D deficient (<50 nmol/L). Only 14 patients had a formal diagnosis of osteoporosis at presentation, with 63 patients claiming daily sun exposure in line with recommendations for vitamin D sufficiency. CONCLUSIONS: Our data suggest that the prevalence of vitamin D insufficiency and deficiency is common in patients presenting with fractures in southeastern Australia and is not confined to elderly patients. All patients with fractures should be assessed for vitamin D levels and treated in accordance with vitamin D deficiency guidelines.

Is low vitamin D status a risk factor for food allergy? Current evidence and future directions

Studies from several countries have reported an association between latitudes further from the equator and proxy markers of food allergy prevalence. As latitudes further from the equator are associated with lower sun exposure and vitamin D status (VDS), it has been proposed that low VDS may be a risk factor for food allergy. A range of basic science evidence supports the biological plausibility of this hypothesis; and recent work has identified a cross sectional association between low VDS and challenge proven food allergy in infants. Overall, however, the evidence regarding the relationship between VDS and food allergy remains controversial and the limited longitudinal data are discouraging. In this review we consider the evidence for and against low VDS as a risk factor for food allergy and discuss the possibility that other factors (including genetic variables) may contribute to the inconsistent nature of the available observational evidence. We then discuss whether genetic and/or environmental factors may modify the potential influence of VDS on food allergy risk. Finally, we argue that given the rising burden of food allergy, the balance of available evidence regarding the potential relevance of VDS to this phenomenon, and the inherent limitations of the existing observational data, there is a compelling case for conducting randomised clinical trials of vitamin D supplementation for the prevention of food allergy during early life.

Níveis séricos de vitamina D associados com indicadores da síndrome metabólica na população brasileira

Pós-graduação em Ciências Biológicas (Biologia Celular e Molecular) - IBRC

Remodelação cardíaca induzida plea deficiência de vitamina D em ratos. -

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da suplementação de dieta com diferentes doses de vitamina D sobre variáveis cardíacas em ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Vitamin D serum levels are associated with handgrip strength but not with muscle mass or length of hospital stay after hip fracture

Objectives: The aim of this study was to evaluate the association between serum levels of 25(OH) vitamin D-3 with midupper arm muscle circumference (MUAMC), handgrip strength and length of hospital stay (LOS) after hip fracture.Methods: In total, 102 consecutive patients with hip fracture over the age of 65 were admitted to the orthopedic unit and prospectively evaluated. All of the patients were treated according to specific protocols depending on the type of fracture. Anthropometric measurements and handgrip strength were performed, and blood samples were taken for serum biochemistry and 25(OH) vitamin D-3 analysis within the first 72 h of admission. All of the patients were followed during their hospital stay, and the length of stay was recorded.Results: Of the patients, two were excluded because of pathologic fractures. In total, 100 patients with a mean age of 80 +/- 7 y were included in the analysis. Among these patients, 73% were female, and 37% had vitamin D deficiency. The median LOS was 7 (5-11) d. Patients with vitamin D deficiency had lower handgrip strength in univariate analysis. In the multiple linear regression analysis with robust standard error, serum vitamin D levels adjusted by age and sex were associated with handgrip strength but not with MUAMC and LOS after hip fracture.Conclusions: In conclusion, vitamin D serum levels were associated with handgrip strength but not with muscle mass or length of hospital stay after hip fracture. (C) 2015 Elsevier Inc. All rights reserved.