Prevention of urinary tract infections with vitamin D supplementation 20,000 IU per week for five years. Results from an RCT including 511 subjects.

Background: In observational studies vitamin D deficiency is associated with increased risk of infections, whereas the effect of vitamin D supplementation in randomized controlled trials is non-conclusive.

Methods: Five hundred and eleven subjects with prediabetes were randomized to vitamin D3 (20,000 IU per week) versus placebo for five years. Every sixth month, a questionnaire on respiratory tract infections (RTI) (common cold, bronchitis, influenza) and urinary tract infection (UTI) was filled in.

Vitamin D 20,000 IU per Week for Five Years Does Not Prevent Progression From Prediabetes to Diabetes.

Context: Vitamin D deficiency is associated with insulin resistance and risk of future diabetes.

Objective: The objective of the study was to test whether supplementation with vitamin D to subjects with prediabetes will prevent progression to type 2 diabetes mellitus (T2DM).

Design: This was a randomized controlled trial performed in 2008 through 2015.

Effects of vitamin D binding protein phenotypes and vitamin D supplementation on serum total 25(OH)D and directly measured free 25(OH)D.

Objective: To determine the relationship between serum total 25-hydroxyvitamin D (25(OH)D), directly measured free 25(OH)D and calculated free 25(OH)D with regard to vitamin D-binding protein (DBP) phenotypes, sex, BMI, age and season, and their interrelationship to vitamin D supplementation.

Design, Patients And Interventions: A randomized controlled trial with 20 000 IU of vitamin D3 per week or placebo for 12 months was designed. A total of 472 subjects, 236 in each of the intervention groups, were included in the analyses.

No effect of high-dose vitamin D supplementation on glycemic status or cardiovascular risk factors in subjects with prediabetes.

Objective: In observational studies, low serum 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with insulin resistance and other risk factors for cardiovascular disease.

Research Design And Methods: We present 1-year data from an ongoing 5-year trial in 511 individuals with impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) randomly assigned to 20,000 IU/week vitamin D3 or placebo. An oral glucose tolerance test was performed at baseline and after 1 year.