BACKGROUND The impact of season when determining a serum 25-hydroxyvitamin D (S-25OHD) cut-off level for optimal bone health is unknown. OBJECTIVE To investigate the relative importance of S-25OHD for bone mineral density (BMD) by season. METHODS A subcohort of 5002 Swedish women (mean age 68 years), randomly selected from a large population-based longitudinal cohort study with repeat dieta...

INTRODUCTION Serum 25-hydroxyvitamin D (25OHD) deficiency (<50 nmol/l or 20 ng/ml) has been associated with increased blood pressure (BP) in observational studies. A paucity of data on this relationship is available in Latin American or child populations. This study investigates the association between 25OHD levels and BP in adolescents at risk for vitamin D deficiency in 2 Peruvian settings. ...

CONTEXT There is a controversy regarding the definition of vitamin D insufficiency as it relates to bone health. OBJECTIVE The objective of the study was to examine the evidence for a threshold value of serum 25-hydroxyvitamin D (25OHD) that defines vitamin D insufficiency as it relates to bone health. DESIGN AND PARTICIPANTS This was a cross-sectional analysis of baseline data in 488 elder...

OBJECTIVES This study was designed to determine mean serum concentrations of 25-hydroxyvitamin D (25OHD) in postmenopausal women with low bone mineral density (BMD), to find the cutoff of parathormone (PTH) elevation, and to evaluate the correlation 25OHD with BMD, biochemical parameters and vertebral fracture presence. METHODS Transversal study, with collection of 25OHD and PTH, and determin...

Low vitamin D status has been implicated in several chronic medical conditions and unfavorable health outcomes. Our goal was to investigate whether serum 25-hydroxyvitamin D (25OHD) levels are a potentially modifiable risk factor for anemia in a nationally representative cohort of community-dwelling individuals in the United States. We performed a cross-sectional study of 5456 individuals (≥17 ...

CONTEXT There is no consensus on the definition of vitamin D deficiency for bone health based on serum 25-hydroxyvitamin D (25OHD) levels. OBJECTIVE Our objective was to determine whether thresholds exist for associations between 25OHD levels and bone outcomes and if low 25OHD levels have adverse effects on bone health. DESIGN This is a cross-sectional study. PARTICIPANTS This study inclu...

Multiple sclerosis (MS) incidence and serum 25-hydroxyvitamin D (25OHD) levels vary by race/ethnicity. We examined the consistency of beneficial effects of 25OHD and/or sun exposure for MS risk across multiple racial/ethnic groups. We recruited incident MS cases and controls (blacks 116 cases/131 controls; Hispanics 183/197; whites 247/267) from the membership of Kaiser Permanente Southern Cali...

BACKGROUND It has been shown that many women with polycystic ovary syndrome (PCOS) are 25-hydroxyvitamin D (25OHD) insufficient. Both statin treatment and vitamin D supplementation have been shown to improve biochemical hyperandrogenemia, insulin resistance, and markers of inflammation in patients with PCOS, raising the possibility that some of the statin effects are mediated through vitamin D....

Vitamin D is well known for its role in promoting skeletal health. Vitamin D status is determined conventionally by circulating 25-dihydroxyvitamin D (25OHD) concentration. There is evidence indicating that circulating 25OHD concentration is affected by variation in Gc, the gene encoding the vitamin D binding protein (DBP). The composite genotype of two single nucleotide polymorphisms (rs7041 a...

BACKGROUND AND OBJECTIVES Darker skin pigmentation and aging are known factors influencing the body's ability to synthesize adequate amounts of vitamin D (25OHD). The objective of this study is to determine the 25OHD insufficiency in elderly African American females of low socioeconomic status (SES) in a southern latitude during springtime sun exposure. METHODS Patients >or= 70 years old who ...