Worldwide vitamin D status van Schoor, Natasja M., Ph.D; Lips, Paul, Ph.D, M.D
Best Practice & Research Clinical Endocrinology & Metabolism,
08/2011, Volume:
25, Issue:
4
Journal Article
Peer reviewed
The aim of the present study is to summarize existing literature on vitamin D levels in adults in different continents and different countries woldwide. The best determinant of vitamin D status is ...the serum concentration of 25-hydroxyvitamin D (25(OH)D). Most investigators agree that serum 25(OH)D should be higher than 50 nmol/l, but some recommend higher serum levels. Traditional risk groups for vitamin D deficiency include pregnant women, children, older persons, the institutionalized, and non-western immigrants. This chapter shows that serum 25(OH)D levels are not only suboptimal in specific risk groups, but also in adults in many countries. Especially, in the Middle-East and Asia, vitamin D deficiency in adults is highly prevalent.
Abstract
Background
The aim was to investigate the associations of sarcopenia as defined by European Working Group on Sarcopenia in Older People (EWGSOP) and Foundation for the National Institutes of ...Health (FNIH) Sarcopenia Project, and their underlying components, with the incidence of recurrent falling and fractures.
Methods
In 498 older men and women (mean age = 75.2 SD = 6.4) from the Longitudinal Aging Study Amsterdam (LASA), the sarcopenia components lean mass (DXA), handgrip strength (handheld dynamometer), and gait speed were measured. Data on falls (3-year follow-up) and fractures (10-year follow-up) were collected. Cox regression analyses were performed, adjusting for age, sex, and total body fat.
Results
Recurrent falling occurred in 130 persons and 60 persons experienced a fracture during follow-up. Participants who were identified as sarcopenic based on the FNIH definitions had a more than 2-fold increased risk to become a recurrent faller. There was no association between sarcopenia based on the EWGSOP definition and incidence of recurrent falling. When the sarcopenia components were examined individually, only a low grip strength was associated with incidence of recurrent falling, independent of a low lean mass or a slow gait speed. Sarcopenia according to both definitions was not associated with incident fractures, which may be caused by low statistical power.
Conclusion
Sarcopenia according to the FNIH definitions, but not according to the EWGSOP definition was associated with recurrent falling. When examining the individual components, only a low grip strength was independently associated with recurrent falling. No associations between sarcopenia with incidence of fractures were found.
Vitamin D status can be assessed by measuring concentrations of 25‐hydroxyvitamin D (25(OH)D). Sunlight is the most important source of vitamin D and stimulates the production of vitamin D3 in the ...skin during the summer, depending on age, skin pigmentation, clothing style, and sunscreen use. Seasonal variation in serum 25(OH)D is between 10 and 20 nmol/L in adults and almost absent in nursing home residents. Sunscreen use decreases, but does not abolish, vitamin D production in the skin. Clothing style has a large influence on vitamin D production. Furthermore, vitamin D status can be improved by ingestion of fatty fish and the fortification of milk or orange juice. A high dietary calcium intake has a vitamin D–sparing effect, because it increases the half‐life of 25(OH)D. A combination of sunlight exposure, nutrition, food fortification, and supplements is desirable to obtain sufficient vitamin D status in the population of most countries throughout the year.
A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D (25OHD) levels on non-skeletal outcomes. We performed a systematic quantitative review on ...characteristics of randomized clinical trials (RCTs) included in meta-analyses (MAs) on non-skeletal effects of vitamin D supplementation.
We identified systematic reviews (SR) reporting summary data in terms of MAs of RCTs on selected non-skeletal outcomes. For each outcome, we summarized the results from available SRs and scrutinized included RCTs for a number of predefined characteristics. We identified 54 SRs including data from 210 RCTs. Most MAs as well as the individual RCTs reported null-findings on risk of cardiovascular diseases, type 2 diabetes, weight-loss, and malignant diseases. Beneficial effects of vitamin D supplementation was reported in 1 of 4 MAs on depression, 2 of 9 MAs on blood pressure, 3 of 7 MAs on respiratory tract infections, and 8 of 12 MAs on mortality. Most RCTs have primarily been performed to determine skeletal outcomes, whereas non-skeletal effects have been assessed as secondary outcomes. Only one-third of the RCTs had low level of 25OHD as a criterion for inclusion and a mean baseline 25OHD level below 50 nmol/L was only present in less than half of the analyses.
Published RCTs have mostly been performed in populations without low 25OHD levels. The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels.
Abstract The main effect of the active vitamin D metabolite 1,25(OH)2D is to stimulate the absorption of calcium from the gut. The consequences of vitamin D deficiency are secondary ...hyperparathyroidism and bone loss, leading to osteoporosis and fractures, mineralization defects, which may lead to osteomalacia in the long term, and muscle weakness, causing falls and fractures. Vitamin D status is related to bone mineral density and bone turnover. Vitamin D supplementation may decrease bone turnover and increase bone mineral density. Several randomized placebo-controlled trials with vitamin D and calcium showed a significant decrease in fracture incidence. However, very high doses of vitamin D once per year may have adverse effects. When patients with osteoporosis are treated with a bisphosphonate, they should receive a vitamin D and calcium supplement unless the patient is vitamin D replete. These subjects are discussed in detail in this review. Finally, the knowledge gaps and research agenda are discussed.
Context:
Public health authorities around the world recommend widely variable supplementation strategies for adults, whereas several professional organizations, including The Endocrine Society, ...recommend higher supplementation.
Methods:
We analyzed published randomized controlled clinical trials to define the optimal intake or vitamin D status for bone and extraskeletal health.
Conclusions:
The extraskeletal effects of vitamin D are plausible as based on preclinical data and observational studies. However, apart from the beneficial effects of 800 IU/d of vitamin D3 for reduction of falls in the elderly, causality remains yet unproven in randomized controlled trials (RCTs). The greatest risk for cancer, infections, cardiovascular and metabolic diseases is associated with 25-hydroxyvitamin D (25OHD) levels below 20 ng/mL. There is ample evidence from RCTs that calcium and bone homeostasis, estimated from serum 1,25-dihydroxyvitamin D and PTH, calcium absorption, or bone mass, can be normalized by 25OHD levels above 20 ng/mL. Moreover, vitamin D supplementation (800 IU/d) in combination with calcium can reduce fracture incidence by about 20%. Such a dose will bring serum levels of 25OHD above 20 ng/mL in nearly all postmenopausal women. Based on calculations of the metabolic clearance of 25OHD, a daily intake of 500–700 IU of vitamin D3 is sufficient to maintain serum 25OHD levels of 20 ng/mL. Therefore, the recommendations for a daily intake of 1500–2000 IU/d or serum 25OHD levels of 30 ng or higher for all adults or elderly subjects, as suggested by The Endocrine Society Task Force, are premature. Fortunately, ongoing RCTs will help to guide us to solve this important public health question.
Folic acid and vitamin B12 play key roles in one-carbon metabolism. Disruption of one-carbon metabolism may be involved in the risk of cancer. Our aim was to assess the long-term effect of ...supplementation with both folic acid and vitamin B12 on the incidence of overall cancer and on colorectal cancer in the B Vitamins for the Prevention of Osteoporotic Fractures (B-PROOF) trial.
Long-term follow-up of B-PROOF trial participants (
= 2,524), a multicenter, double-blind randomized placebo-controlled trial designed to assess the effect of 2 to 3 years daily supplementation with folic acid (400 μg) and vitamin B12 (500 μg) versus placebo on fracture incidence. Information on cancer incidence was obtained from the Netherlands cancer registry (Integraal Kankercentrum Nederland), using the International Statistical Classification of Disease (ICD-10) codes C00-C97 for all cancers (except C44 for skin cancer), and C18-C20 for colorectal cancer.
Allocation to B vitamins was associated with a higher risk of overall cancer 171 (13.6%) vs. 143 (11.3%); HR 1.25; 95% confidence interval (CI), 1.00-1.53,
= 0.05. B vitamins were significantly associated with a higher risk of colorectal cancer 43(3.4%) vs. 25(2.0%); HR 1.77; 95% CI, 1.08-2.90,
= 0.02.
Folic acid and vitamin B12 supplementation was associated with an increased risk of colorectal cancer.
Our findings suggest that folic acid and vitamin B12 supplementation may increase the risk of colorectal cancer. Further confirmation in larger studies and in meta-analyses combining both folic acid and vitamin B12 are needed to evaluate whether folic acid and vitamin B12 supplementation should be limited to patients with a known indication, such as a proven deficiency.
The prevalence of risk factors for falls increases during middle-age, but the prevalence of falls in this age-range is often overlooked and understudied. The aim was to calculate the prevalence of ...falls in middle-aged adults (aged 40-64 years) from four countries. Data were from four population-based cohort studies from Australia (Australian Longitudinal Study on Women's Health, n = 10556, 100% women, 51-58 years in 2004), Ireland (The Irish Longitudinal Study on Ageing, n = 4968, 57.5% women, 40-64 years in 2010), the Netherlands (Longitudinal Aging Study Amsterdam, n = 862, 51.6% women, 55-64 years in 2012-13) and Great Britain (MRC National Survey of Health and Development, n = 2821, 50.9% women, 53 years in 1999). In each study, falls assessment was based on recall of any falls in the past year. The prevalence of falls was calculated for the total group, for each country, for men and women separately, and for 5-year age-bands. The prevalence was higher in Australia (27.8%, women only) and the Netherlands (25.1%) than in Ireland (17.6%) and Great Britain (17.8%, p<0.001). Women (27.0%) had higher prevalences than men (15.2%, p<0.001). The prevalence increased from 8.7% in 40-44 year olds to 29.9% in 60-64 year olds in women, and from 14.7% in 45-49 year olds to 15.7% in 60-64 year olds in men. Even within 5-year age-bands, there was substantial variation in prevalence between the four cohorts. Weighting for age, sex and education changed the prevalence estimates by less than 2 percentage points. The sharp increase in prevalence of falls in middle-age, particularly among women supports the notion that falls are not just a problem of old age, and that middle-age may be a critical life stage for preventive interventions.
Evidence on the association between single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and depressive symptoms is inconclusive.
The primary aim of the study was to investigate the ...association between SNPs in the VDR gene and depressive symptoms.
In a sample of older adults from the Longitudinal Ageing Study Amsterdam (n = 922), depressive symptoms were assessed using the Centre for Epidemiological Studies Depression scale (CES-D scale) at baseline and after 3, 6, and 10 y of follow-up. Blood samples for SNP and serum 25-hydroxyvitamin D3 (25(OH)D3) determination were obtained at baseline. The association between 13 SNPs in the VDR gene and the course of depressive symptoms were evaluated using linear mixed models. The interaction between SNPs and serum 25(OH)D3 in relation to depressive symptoms was evaluated using multiple linear regression.
No SNPs were associated with the course of depressive symptoms. Significant interactions between serum 25(OH)D3 and SNPs in the VDR gene were found. Stratified analysis revealed that within the GG genotype strata, 10 nmol/L higher serum 25(OH)D3 was associated with 0.27 (95% CI: −0.50, −0.04) and 0.23 (95% CI: −0.48, 0.02) lower scores on the CES-D scale for Cdx-2 and 1b-G-886A, respectively. This association was not found in persons having the GA or AA genotype.
No SNPs are associated with the course of depressive symptoms. Stratified analysis shows that the effect of serum 25(OH)D3 concentrations on depressive symptoms is different among genotypes of Cdx-2 and 1b-G-886A. Future research should elucidate on the function of Cdx-2 and 1b-G-886A to describe their effect.
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