Predictors of serum 25-hydroxyvitamin D concentrations among postmenopausal women: the Women’s Health Initiative Calcium plus Vitamin D Clinical Trial.
March 15th, 2010 Posted by: admin
| Related Articles |
Predictors of serum 25-hydroxyvitamin D concentrations among postmenopausal women: the Women’s Health Initiative Calcium plus Vitamin D Clinical Trial.
Am J Clin Nutr. 2010 Mar 10;
Authors: Millen AE, Wactawski-Wende J, Pettinger M, Melamed ML, Tylavsky FA, Liu S, Robbins J, Lacroix AZ, Leboff MS, Jackson RD
BACKGROUND: It is unclear how well surrogate markers for vitamin D exposure (eg, oral intake of vitamin D and estimates of sunlight exposure), with and without consideration of other potential predictors of 25-hydroxyvitamin D [25(OH)D] concentrations, similarly rank individuals with respect to 25(OH)D blood concentrations. OBJECTIVE: The objective was to determine how much variation in serum 25(OH)D concentrations (nmol/L) could be explained by a predictive model with the use of different vitamin D surrogate makers (latitude of residence, mean annual regional solar irradiance estimates, and oral sources) and other individual characteristics that might influence vitamin D status. DESIGN: A random sample of 3055 postmenopausal women (aged 50-70 y) participating in 3 nested case-control studies of the Women’s Health Initiative Calcium plus Vitamin D Clinical Trial was used. Serum 25(OH)D values, assessed at year 1 (1995-2000), and potential predictors of 25(OH)D concentrations, assessed at year 1 or Women’s Health Initiative baseline (1993-1998), were used. RESULTS: More than half of the women (57.1%) had deficient (<50 nmol/L) concentrations of 25(OH)D. Distributions of 25(OH)D concentrations by level of latitude of residence, mean annual regional solar irradiance, and intake of vitamin D varied considerably. The predictive model for 25(OH)D explained 21% of the variation in 25(OH)D concentrations. After adjustment for month of blood draw, breast cancer status, colorectal cancer status, fracture status, participation in the hormone therapy trial, and randomization to the dietary modification trial, the predictive model included total vitamin D intake from foods and supplements, waist circumference, recreational physical activity, race-ethnicity, regional solar irradiance, and age. CONCLUSIONS: Surrogate markers for 25(OH)D concentrations, although somewhat correlated, do not adequately reflect serum vitamin D measures. These markers and predictive models of blood 25(OH)D concentrations should not be given as much weight in epidemiologic studies of cancer risk.
PMID: 20219959 [PubMed - as supplied by publisher]
Similar Posts:
- Serum vitamin C and the prevalence of vitamin C deficiency in the United States: 2003-2004 National Health and Nutrition Examination Survey (NHANES).
- Daily intake of 4 to 7 {micro}g dietary vitamin B-12 is associated with steady concentrations of vitamin B-12-related biomarkers in a healthy young population.
- Low serum folate and vitamin B-6 are associated with an altered cancellous bone structure in humans.
- Micronutrient concentrations and subclinical atherosclerosis in adults with HIV.
- Effect of 5 y of calcium plus vitamin D supplementation on change in circulating lipids: results from the Women’s Health Initiative.
- Longitudinal study of serum carotenoid, retinol, and tocopherol concentrations in relation to breast cancer risk among postmenopausal women.
- Folic acid source, usual intake, and folate and vitamin B-12 status in US adults: National Health and Nutrition Examination Survey (NHANES) 2003-2006.
- Functional genetic variants of glutathione S-transferase protect against serum ascorbic acid deficiency.
- Low-fat dietary pattern and lipoprotein risk factors: the Women’s Health Initiative Dietary Modification Trial.
- Low-fat dietary pattern and lipoprotein risk factors: the Women’s Health Initiative Dietary Modification Trial.