title: Depression and serum 25-hydroxyvitamin D in older adults living at northern latitudes - AGES-Reykjavik Study.
abstract: Low vitamin D status may be associated with depression. Few studies have examined vitamin D and depression in older adults living at northern latitudes. The present study cross-sectionally investigated serum 25-hydroxyvitamin D (25(OH)D) status and depression among 5006 community-dwelling older persons (66-96 years) living in Iceland (latitudes 64-66°N). Depressive symptoms were measured by the fifteen-item Geriatric Depression Scale (GDS-15). Current major depressive disorder was assessed according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria. Serum 25(OH)D was analysed using chemiluminescence immunoassay and categorised into three groups: deficient (<30 nmol/l); inadequate (30-49·9 nmol/l); and adequate (≥50 nmol/l). There were twenty-eight (2 %) men and fifty (1 %) women with current major depressive disorder. Mean GDS-15 scores for men and women with adequate vitamin D concentrations were 2·1 and 2·2, respectively. Men and women with deficient v. adequate vitamin D status had more depressive symptoms (higher GDS-15 scores) (difference 0·7 (95 % CI 0·4, 0·9) and 0·4 (95 % CI 0·1, 0·6), respectively). Furthermore, men with deficient vitamin D status were more likely to have current major depressive disorder (adjusted OR 2·51; 95 % CI 1·03, 6·13) compared with men with adequate vitamin D status. Associations among women were not significant. In this older population living at northern latitudes, deficient vitamin D status may be associated with depression. Further investigations are warranted to evaluate the pathways that may be associated with risk of depression among older adults.
authors.affiliation: Unit for Nutrition Research , Landspitali - The National University Hospital of Iceland and Faculty of Food Science and Nutrition , School of Health Sciences , University of Iceland , Eiriksgata 29 , 101 Reykjavik , Iceland.
authors.forename: Cindy M
authors.initials: CM
authors.lastname: Imai
authors.affiliation: Unit for Nutrition Research , Landspitali - The National University Hospital of Iceland and Faculty of Food Science and Nutrition , School of Health Sciences , University of Iceland , Eiriksgata 29 , 101 Reykjavik , Iceland ; Department of Epidemiology Research , Centre for Fetal Programming , Statens Serum Institut , 5, Artillerivej , 2300 Copenhagen S , Denmark.
authors.forename: Thorhallur I
authors.initials: TI
authors.lastname: Halldorsson
authors.affiliation: Icelandic Heart Association , Holtasmari 1 , 201 Kopavogur , Iceland.
authors.forename: Gudny
authors.initials: G
authors.lastname: Eiriksdottir
authors.affiliation: Division of Epidemiology and Clinical Applications , National Eye Institute , 10 Center Drive , MSC 1204 , Bethesda , MD 20892-1204 , USA.
authors.forename: Mary F
authors.initials: MF
authors.lastname: Cotch
authors.affiliation: Unit for Nutrition Research , Landspitali - The National University Hospital of Iceland and Faculty of Food Science and Nutrition , School of Health Sciences , University of Iceland , Eiriksgata 29 , 101 Reykjavik , Iceland.
authors.forename: Laufey
authors.initials: L
authors.lastname: Steingrimsdottir
authors.affiliation: Unit for Nutrition Research , Landspitali - The National University Hospital of Iceland and Faculty of Food Science and Nutrition , School of Health Sciences , University of Iceland , Eiriksgata 29 , 101 Reykjavik , Iceland.
authors.forename: Inga
authors.initials: I
authors.lastname: Thorsdottir
authors.affiliation: National Institute on Aging, Laboratory of Epidemiology, and Population Sciences , 7201 Wisconsin Avenue , Bethesda , MD 20892-9205 , USA.
authors.forename: Lenore J
authors.initials: LJ
authors.lastname: Launer
authors.affiliation: National Institute on Aging, Laboratory of Epidemiology, and Population Sciences , 7201 Wisconsin Avenue , Bethesda , MD 20892-9205 , USA.
authors.forename: Tamara
authors.initials: T
authors.lastname: Harris
authors.affiliation: Icelandic Heart Association , Holtasmari 1 , 201 Kopavogur , Iceland ; Faculty of Medicine , School of Health Sciences , University of Iceland , Vatnsmyrarvegur 16 , 101 Reykjavik , Iceland.
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Gudnason
authors.affiliation: Unit for Nutrition Research , Landspitali - The National University Hospital of Iceland and Faculty of Food Science and Nutrition , School of Health Sciences , University of Iceland , Eiriksgata 29 , 101 Reykjavik , Iceland.
authors.forename: Ingibjorg
authors.initials: I
authors.lastname: Gunnarsdottir
keywords: 25(OH)D, 25-hydroxyvitamin D; AGES-Reykjavik, Age, Gene/Environment Susceptibility–Reykjavik; Cross-sectional analyses; Depression; GDS, Geriatric Depression Scale; MINI, Mini-International Neuropsychiatric Interview; Nutritional epidemiology; Older adults; Vitamin D