Low serum 25-hydroxyvitamin D (25OHD) is associated with osteoporosis and osteoporotic fracture, but it remains uncertain whether these associations are causal. We conducted a Mendelian randomization (MR) study of 1,824 postmenopausal Chinese women to examine whether the detected associations between serum 25OHD and bone mineral density (BMD) and bone metabolism markers were causal. In observat...

The range of 25-hydroxyvitamin D (25OHD) concentration was determined in a young healthy population based on bone metabolism parameters and environmental and behavioral aspects. We studied 121 healthy young volunteers (49 men, 72 women) living in São Paulo (23 masculine 34' south latitude) belonging to three occupational categories: indoor workers (N = 28), medical school students (N = 44), and...

Although vitamin D status may be a modifiable risk factor for various respiratory ailments, limited data exists regarding its role in sinonasal infections. Our goal was to investigate the association of 25-hydroxyvitamin D (25OHD) levels with acute rhinosinusitis (ARS) in a large, nationally representative sample of non-institutionalized individuals from the United States. In this cross-section...

Low vitamin D and insulin resistance are common in polycystic ovary syndrome (PCOS) and associated with higher inter- and intra-muscular adipose tissue (IMAT). We investigated associations between vitamin D, IMAT and insulin resistance in a cross-sectional study of 40 women with PCOS and 30 women without PCOS, and pre- and post-exercise in a 12-week intervention in 16 overweight participants (1...

BACKGROUND Moderate to severe premenstrual syndrome (PMS) affects 8-20 percent of premenopausal women. Previous studies suggest that high dietary vitamin D intake may reduce risk. However, vitamin D status is influenced by both dietary vitamin D intake and sunlight exposure and the association of vitamin D status with PMS remains unclear. METHODS We assessed the relation of plasma 25-hydroxyv...

Vitamin D status, as measured by serum 25-hydroxy vitamin D (s-25OHD), is important to human health. Dermal 25OHD production depends on UVB light that is influenced by latitude. We aimed to identify factors important to the production of s-25OHD in Arctic people and investigated subjects living in the town of Ilulissat and the settlement of Saqqaq in North Greenland (70°N) during the four seaso...

Little is known about vitamin D status in preterm infants and their response to supplementation. To investigate this, we assessed serum 25-hydroxyvitamin D (25OHD) levels using RIA in a consecutive sample of stable preterm very low birth weight (VLBW) infants (born ≤ 32 weeks gestation or birth weight ≤ 1·5 kg), and we explored associated factors. Serum 25OHD level was first assessed once infan...

BACKGROUND Several studies suggest that 24,25-dihydroxyvitamin D [24,25(OH)₂D] may have an effect on bone mass and metabolism. OBJECTIVE We evaluated the relationship between serum 24,25(OH)₂D levels and bone density and bone metabolism in children with a primary bone disorder-osteogenesis imperfecta (OI). MATERIALS AND METHODS The study included 132 patients (age, 1.1 to 17.9 yr; 67 girls)...

OBJECTIVES Analytical and clinical verification of both old and new generations of the Abbott total 25-hydroxyvitamin D (25OHD) assays, and an examination of reference Intervals. METHODS Determination of between-run precision, and Deming comparison between patient sample results for 25OHD on the Abbott Architect, DiaSorin Liaison and AB SCIEX API 4000 (LC-MS/MS). Establishment of uncertainty ...

BACKGROUND The Institute of Medicine 2011 Report on Dietary Reference Intakes for Calcium and Vitamin D specified higher intakes for all age groups compared to the 1997 report, but also cautioned against spurious claims about an epidemic of vitamin D deficiency and against advocates of higher intake requirements. Over 40 years, we have noted marked improvement in vitamin D status but we are con...