Hypovitaminosis D among healthy children in the United States - A review of the current evidence
ABSTRACT To review the published literature on serum 25-hydroxyvitamin D concentrations in US children.
Articles were identified by searching MEDLINE using 25-hydroxyvitamin D, vitamin D, hypovitaminosis D, vitamin D insufficiency, vitamin D deficiency, children, and adolescents as key words and by screening references from original studies.
Studies were included if they fulfilled the following a priori criteria: contained a well-defined sample of children, included only healthy children, presented data on serum 25-hydroxyvitamin D concentrations, were published in the past 10 years, and were conducted in the United States.
Serum 25-hydroxyvitamin D concentrations and prevalence of low vitamin D status (hypovitaminosis D).
Fourteen articles fulfilled the criteria. There were no consistent definitions of hypovitaminosis D; values corresponding to vitamin D deficiency ranged from less than 5 ng/mL to less than 12 ng/mL, and those for vitamin D insufficiency ranged from less than 10 ng/mL to less than 32 ng/mL (to convert 25-hydroxyvitamin D concentrations to nanomoles per liter, multiply by 2.496). The following assays were used: radioimmunoassay (7 studies), competitive binding protein assay (3 studies), automated chemiluminescence protein-binding assay (3 studies), and enzyme-linked immunosorbent assay (1 study). Breastfed infants in winter who did not receive vitamin D supplementation were the most severely vitamin D deficient (78%). Estimates of the prevalence of hypovitaminosis D ranged from 1% to 78%. Older age, winter season, higher body mass index, black race/ethnicity, and elevated parathyroid hormone concentrations were associated with lower 25-hydroxyvitamin D concentrations.
Although overt vitamin D deficiency is no longer common in US children, lesser degrees of vitamin D insufficiency are widespread.
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ABSTRACT: Findings are conflicting about the relationship between vitamin D levels and cardiovascular mortality. We wanted to determine the contribution of vitamin D levels to black-white disparities in cardiovascular mortality. We examined the association of serum 25(OH)D levels with cardiovascular mortality and its contribution to elevated risk among blacks through a retrospective cohort using baseline data from the third National Health and Nutrition Examination Survey 1988-1994 and cause-specific mortality through 2001 using the National Death Index. Using piecewise Poisson regression models, we examined the risk of cardiovascular death (coronary heart disease, heart failure, and stroke) by sample 25(OH)D quartile, adjusting for cardiovascular risk factors, and compared models of adjusted race-related cardiovascular mortality with and without further adjustment for 25(OH)D levels. Participants with 25(OH)D levels in the lowest quartile (mean = 13.9 ng/mL) compared with those in the 3 higher quartiles (mean = 21.6, 28.4, and 41.6 ng/mL) had higher adjusted risk of cardiovascular death (incident rate ratio [IRR] = 1.40; 95% confidence interval [CI], 1.16-1.70). The higher age- and sex-adjusted cardiovascular mortality observed in blacks vs whites (IRR = 1.38; 95% CI, 1.13-1.70) was attenuated (IRR = 1.14; 95% CI, 0.91-1.44) by adjustment for 25(OH)D levels and fully eliminated with further adjustment for income (IRR=1.01; 95% CI, 0.82-1.24). Low serum levels of 25(OH)D are associated with increased cardiovascular mortality in a nationally representative US sample. Black-white differences in 25(OH)D levels may contribute to excess cardiovascular mortality in blacks. Interventional trials among persons with low vitamin D levels are needed to determine whether oral supplementation improves cardiovascular outcomes.The Annals of Family Medicine 01/2010; 8(1):11-8. DOI:10.1370/afm.1035 · 4.57 Impact Factor
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ABSTRACT: Methods for longitudinal bunch charge distribution monitoring can be divided onto two groups: the usings of coherent or incoherent radiation of the bunch electrons. The former can be used for estimation of the RMS bunch length, and the latter-for the bunch charge distribution measurements. Methods of the bunch distribution monitoring with subpicosecond resolution based on use of secondary electrons, transition, Cherenkov or bremsstrahlung radiation are considered
- PEDIATRICS 11/2008; 122(4):907-8; author reply 908-9. DOI:10.1542/peds.2008-1743 · 5.30 Impact Factor