title: Diet, environmental factors, and lifestyle underlie the high prevalence of vitamin D deficiency in healthy adults in Scotland, and supplementation reduces the proportion that are severely deficient.
abstract: Vitamin D deficiency has recently been implicated as a possible risk factor in the etiology of numerous diseases, including nonskeletal conditions. In humans, skin synthesis following exposure to UVB is a potent source of vitamin D, but in regions with low UVB, individuals are at risk of vitamin D deficiency. Our objectives were to describe the prevalence of vitamin D deficiency and to investigate determinants of plasma 25-hydroxyvitamin D (25-OHD) concentrations in a high northern latitude country. Detailed dietary, lifestyle, and demographic data were collected for 2235 healthy adults (21-82 y) from Scotland. Plasma 25-OHD was measured by liquid chromatography-tandem MS. Among study participants, 34.5% were severely deficient (25-OHD <25 nmol/L) and 28.9% were at high risk of deficiency (25-40 nmol/L). Only 36.6% of participants were at low risk of vitamin D deficiency or had adequate levels (>40 nmol/L). Among participants who were taking supplements, 21.3% had a May-standardized 25-OHD concentration >50 nmol/L, 54.2% had 25-50 nmol/L, and 24.5% had <25 nmol/L, whereas this was 15.6, 43.3, and 41%, respectively, among those who did not take supplements (P < 0.0001). The most important sources of vitamin D were supplements and fish consumption. Vitamin D deficiency in Scotland is highly prevalent due to a combination of insufficient exposure to UVB and insufficient dietary intake. Higher dietary vitamin D intake modestly improved the plasma 25-OHD concentration (P = 0.02) and reduced the proportion of severely deficient individuals (P < 0.0001). In regions with low UVB exposure, dietary and supplement intake may be much more important than previously thought and consideration should be given to increasing the current recommended dietary allowance of 0-10 μg/d for adults in Scotland.
authors.affiliation: Centre for Population Health Sciences, University of Edinburgh, Edinburgh EH8 9AG, UK. lina.zgaga@ed.ac.uk
authors.forename: Lina
authors.initials: L
authors.lastname: Zgaga
authors.forename: Evropi
authors.initials: E
authors.lastname: Theodoratou
authors.forename: Susan M
authors.initials: SM
authors.lastname: Farrington
authors.forename: Felix
authors.initials: F
authors.lastname: Agakov
authors.forename: Albert
authors.initials: A
authors.lastname: Tenesa
authors.forename: Marion
authors.initials: M
authors.lastname: Walker
authors.forename: Susan
authors.initials: S
authors.lastname: Knox
authors.forename: A Michael
authors.initials: AM
authors.lastname: Wallace
authors.forename: Roseanne
authors.initials: R
authors.lastname: Cetnarskyj
authors.forename: Geraldine
authors.initials: G
authors.lastname: McNeill
authors.forename: Janet
authors.initials: J
authors.lastname: Kyle
authors.forename: Mary E
authors.initials: ME
authors.lastname: Porteous
authors.forename: Malcolm G
authors.initials: MG
authors.lastname: Dunlop
authors.forename: Harry
authors.initials: H
authors.lastname: Campbell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002853:Chromatography, Liquid; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012606:Scotland / Q000453:epidemiology; D053719:Tandem Mass Spectrometry; D014807:Vitamin D / Q000008:administration & dosage*; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D