Hydroxyvitamin D Concentration (hydroxyvitamin + d_concentration)

Distribution by Scientific Domains

Selected Abstracts

Vitamin D: criteria for safety and efficacy

Robert P Heaney
The functional status indicator for vitamin D, for both safety and efficacy, is serum 25-hydroxyvitamin D concentration. Efficacy for several health endpoints requires levels of 80 nmol/L or higher. Toxicity occurs at levels of 500 nmol/L or higher. The input needed for efficacy, in addition to typical food and cutaneous inputs, will usually be 1000,2000 IU/day of supplemental cholecalciferol. Toxicity is associated only with excessive supplemental intake (usually well above 20,000 IU/day). [source]

Vitamin D status and acute lower respiratory infection in early childhood in Sylhet, Bangladesh

DE Roth
Abstract Aim: Acute lower respiratory tract infection (ALRI) is the most important global cause of childhood death. Micronutrient deficiencies may increase the risk of ALRI. A case,control study was conducted to assess the association between vitamin D status and ALRI in rural Bangladesh. Methods: Children aged 1,18 months hospitalized with ALRI (cases) were individually matched to controls on age, sex, and village (N = 25 pairs). The mean serum 25-hydroxyvitamin D concentration [25(OH)D] in cases and controls was compared using paired t -test. The unadjusted and adjusted odds of ALRI were assessed by multivariate conditional logistic regression. Results: Mean [25(OH)D] was significantly lower among ALRI cases than controls (29.1 nmol/L vs. 39.1 nmol/L; p = 0.015). The unadjusted odds of ALRI was halved for each 10 nmol/L increase in [25(OH)D] (OR 0.53, 95% CI 0.30,0.96). Adjustment for confounders increased the magnitude of the association. Conclusion: Vitamin D status was associated with early childhood ALRI in a matched case,control study in rural Bangladesh. Randomized trials may establish whether interventions to improve vitamin D status can reduce the burden of ALRI in early childhood. [source]

Maternal plasma 25-hydroxyvitamin D concentration and birthweight, growth and bone mineral accretion of Gambian infants

Ann Prentice
No abstract is available for this article. [source]

Baseline serum 25-hydroxyvitamin D concentrations in the Tromsų Study 1994,95 and risk of developing type 2 diabetes mellitus during 11 years of follow-up

G. Grimnes
Diabet. Med. 27, 1107,1115 (2010) Abstract Aims, We wanted to test the hypothesis that low serum 25-hydroxyvitamin D (25(OH)D) concentrations are associated with increased risk of developing Type 2 diabetes mellitus (DM) in a population-based cohort during 11 years of follow-up. Methods, The analyses included 4157 non-smokers and 1962 smokers from the Tromsų Study 1994,95 without diabetes at baseline. Subsequent Type 2 DM was defined using a hospital journal-based end-point registry, completed through the year 2005. Participants were allocated into quartiles of serum 25(OH)D within each month to account for seasonal variation, and serum 25(OH)D values both as a continuous variable and in quartiles were used in Cox regression models. The analyses were stratified by smoking. Adjustments were made for age, sex, body mass index (BMI), physical activity and, in non-smokers, former smoking. Results, Type 2 DM was registered in 183 non-smoking and 64 smoking participants. Using the fourth (highest) quartile of serum 25(OH)D as the reference, non-smoking participants in the third, second and first quartiles had age- and sex-adjusted hazard ratios (95% confidence intervals) of incident Type 2 DM of 1.00 (0.62,1.61), 1.50 (0.97,2.31) and 1.89 (1.25,2.88), respectively, whereas the corresponding values for smokers were 1.79 (0.77,4.19), 2.33 (1.02,5.35) and 2.68 (1.18,6.08). Adjustment for BMI attenuated the hazard ratios, and they were no longer significant. Conclusions, Baseline serum 25(OH)D was inversely associated with subsequent Type 2 DM in a population-based 11 year follow-up study, but not after adjustment for BMI. Randomized trials are needed to define the possible role of serum 25(OH)D status, and thereby the role of supplementation, in the prevention of Type 2 DM. [source]