title: The importance of dose, frequency and duration of vitamin D supplementation for plasma 25-hydroxyvitamin D.
abstract: The importance of dose, frequency and duration of vitamin D supplementation for plasma 25(OH)D levels is not well described and rarely reported for supplementation that exceeds 2000 IU per day. The objective is to examine dose, frequency and duration of supplementation in relation to plasma 25(OH)D in a large population-based sample. We accessed data on 2714 volunteers that contributed to 4224 visits and applied multilevel regression. Compared to not using supplements, a minimum regimen of 1000-2000 IU once or twice per week for one month was not effective in raising 25(OH)D. Compared to this minimum regimen, higher doses of 2000-3000, 3000-4000, and 5000 IU or more were associated with a 7.49, 13.19 and 30.22 nmol/L 25(OH)D increase, respectively; frequencies of three to four, five to six and seven times/week were associated with a 5.44, 16.52 and 30.69 nmol/L increase, respectively; and supplementation of five months or longer was associated with an increase of 6.68 nmol/L (p < 0.01 for all). Age, body weight, physical activity, smoking, and self-rated health were significantly associated with 25(OH)D. Whereas dose, frequency and duration of supplementation are important to healthy subjects committed to optimizing their nutritional status, to the design of clinical trials, individual characteristics and lifestyle contribute substantially to 25(OH)D.
authors.affiliation: School of Public Health, University of Alberta, 3-50 University Terrace, 8303-112 St, Edmonton, AB T6G 2T4, Canada. chaoyisheng@gmail.com.
authors.forename: Yi-Sheng
authors.initials: YS
authors.lastname: Chao
authors.forename: Ludovic
authors.initials: L
authors.lastname: Brunel
authors.forename: Peter
authors.initials: P
authors.lastname: Faris
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Veugelers
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009752:Nutritional Status; D012044:Regression Analysis; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000188:drug therapy; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D