title: Predictors of Vitamin D-Containing Supplement Use in the Australian Population and Associations between Dose and Serum 25-Hydroxyvitamin D Concentrations.
abstract: Despite concerns about vitamin D deficiency in the Australian population, little is known about the prevalence and predictors of vitamin D-containing supplement use. We described the use of vitamin D-containing supplements, and investigated associations between supplemental vitamin D intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, using a single 24-h dietary recall from the 2011-2013 Australian Health Survey (n = 12,153; ages ≥ 2 years). Multiple regression models were used to investigate predictors of vitamin D-containing supplement use in adults, and associations between dose and serum 25(OH)D concentrations/vitamin D sufficiency (≥50 nmol/L), adjusting for potential confounders. The prevalence of vitamin D-containing supplement use was 10%, 6% and 19% in children, adolescents and adults, respectively. Predictors of vitamin D-containing supplement use in adults included being female, advancing age, higher educational attainment, higher socio-economic status, not smoking, and greater physical activity. After adjusting for potential confounders, a 40 IU (1 µg) increase in vitamin D intake from supplements was associated with an increase of 0.41 nmol/L in serum 25(OH)D concentrations (95% CI 0.35, 0.47; p < 0.001). However, the prevalence of vitamin D-containing supplement use was generally low in the Australian population, particularly for single vitamin D supplements, with most supplement users obtaining only low levels of vitamin D from other supplement types.
authors.affiliation: School of Public Health, Curtin University, Bentley 6102, Australia. lucinda.black@curtin.edu.au.
authors.forename: Lucinda J
authors.initials: LJ
authors.lastname: Black
authors.affiliation: Telethon Kids Institute, The University of Western Australia, Subiaco 6008, Australia. peter.jacoby@telethonkids.org.au.
authors.forename: Peter
authors.initials: P
authors.lastname: Jacoby
authors.affiliation: Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong 3125, Australia. caryl.nowson@deakin.edu.au.
authors.forename: Caryl A
authors.initials: CA
authors.lastname: Nowson
authors.affiliation: Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong 3125, Australia. robin.daly@deakin.edu.au.
authors.forename: Robin M
authors.initials: RM
authors.lastname: Daly
authors.affiliation: National Centre for Epidemiology and Population Health, Research School of Population Health, The Australian National University, Canberra 0200, Australia. robyn.lucas@anu.edu.au.
authors.forename: Robyn M
authors.initials: RM
authors.lastname: Lucas
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D004305:Dose-Response Relationship, Drug; D004522:Educational Status; D005260:Female; D006306:Health Surveys / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012044:Regression Analysis; D012737:Sex Factors; D012959:Socioeconomic Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use*; D014808:Vitamin D Deficiency / Q000517:prevention & control; D055815:Young Adult
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-hydroxyvitamin D; supplements; vitamin D