title: Vitamin D insufficiency in Greenlanders on a westernized fare: ethnic differences in calcitropic hormones between Greenlanders and Danes.
abstract: We studied the influence of age, gender, latitude, season, diet and ethnicity on plasma 25-hydroxyvitamin D 25 OHD, PTH, 1,25-dihydroxyvitamin D, vitamin D-binding protein, bone-specific alkaline phosphatase, and osteocalcin levels in 46 Greenlanders living in Nuuk (64 degrees N) on a traditional fare (group A), 45 Greenlanders living in Nuuk on a westernized fare (group B), 54 Greenlanders (group C), and 43 Danes (Group D) living in Denmark (55 degrees N) on a westernized fare. Blood specimens were drawn both summer and winter. Vitamin D insufficiency (plasma 25 OHD <40 nmol/l) was common in all four study groups during summer (23-74%) and winter (42-81%). Compared to groups A and D, vitamin D insufficiency was significantly more frequent in groups B and C. In all groups, summer levels of 25 OHD were above winter levels. Multiple regression analysis revealed a significant effect of ethnicity. Compared to Danes, Greenlanders had higher 1,25-dihydroxyvitamin D levels, but lower 25 OHD and PTH levels despite relatively low plasma calcium concentrations. In addition to ethnicity, 25(OH)D levels were influenced by age, season (summer > winter), and diet (a traditional Inuit diet>westernized diet). Ethnic differences exist between Greenlanders and Danes. Our results suggest that Greenlanders may have an inherent lower "set-point" for calcium-regulated PTH release or an enhanced renal 1,25(OH)(2)D production. In addition to ethnicity, age, season, and diet were important determinants of vitamin D status. Changes from a traditional to a westernized fare are associated with a reduced vitamin D status in Greenlanders. Vitamin D supplementation should be considered.
authors.affiliation: Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus University Hospital, Aarhus, Denmark. rejnmark@post6.tele.dk
authors.forename: L
authors.initials: L
authors.lastname: Rejnmark
authors.forename: M E
authors.initials: ME
authors.lastname: Jørgensen
authors.forename: M B
authors.initials: MB
authors.lastname: Pedersen
authors.forename: J C
authors.initials: JC
authors.lastname: Hansen
authors.forename: L
authors.initials: L
authors.lastname: Heickendorff
authors.forename: A L
authors.initials: AL
authors.lastname: Lauridsen
authors.forename: G
authors.initials: G
authors.lastname: Mulvad
authors.forename: C
authors.initials: C
authors.lastname: Siggaard
authors.forename: H
authors.initials: H
authors.lastname: Skjoldborg
authors.forename: T B
authors.initials: TB
authors.lastname: Sørensen
authors.forename: E B
authors.initials: EB
authors.lastname: Pedersen
authors.forename: L
authors.initials: L
authors.lastname: Mosekilde
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood; D003718:Denmark / Q000453:epidemiology; D004032:Diet; D005260:Female; D005843:Geography; D006116:Greenland / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood*; D010281:Parathyroid Hormone / Q000097:blood*; D015995:Prevalence; D012621:Seasons; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000208:ethnology*
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D015675:Osteocalcin; D014807:Vitamin D; D002118:Calcium