title: Low vitamin D status is associated with more depressive symptoms in Dutch older adults.
abstract: OBJECTIVE
  The existence of vitamin D receptors in the brain points to a possible role of vitamin D in brain function. We examined the association of vitamin D status and vitamin D-related genetic make-up with depressive symptoms amongst 2839 Dutch older adults aged ≥65 years.
  
  
  METHODS
  25-Hydroxyvitamin D (25(OH)D) was measured, and five 'vitamin D-related genes' were selected. Depressive symptoms were measured with the 15-point Geriatric Depression Scale. Results were expressed as the relative risk of the score of depressive symptoms by quartiles of 25(OH)D concentration or number of affected alleles, using the lowest quartile or minor allele group as reference.
  
  
  RESULTS
  A clear cross-sectional and prospective association between serum 25(OH)D and depressive symptom score was observed. Fully adjusted models indicated a 22 % (RR 0.78, 95 % CI 0.68-0.89), 21 % (RR 0.79, 95 % CI 0.68-0.90), and 18 % (RR 0.82, 95 % CI 0.71-0.95) lower score of depressive symptoms in people in the second, third, and fourth 25(OH)D quartiles, when compared to people in the first quartile (P for trend <0.0001). After 2 years of daily 15 µg vitamin D supplementation, similar associations were observed. 25(OH)D concentrations did not significantly interact with the selected genes.
  
  
  CONCLUSIONS
  Low serum 25(OH)D was associated with higher depressive symptom scores. No interactions between 25(OH)D concentrations and vitamin D genetic make-up were observed. In view of the probability of reverse causation, we propose that the association should be further examined in prospective studies as well as in randomized controlled trials.
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands. elske.brouwer-brolsma@wur.nl.
authors.forename: E M
authors.initials: EM
authors.lastname: Brouwer-Brolsma
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: R A M
authors.initials: RA
authors.lastname: Dhonukshe-Rutten
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: J P
authors.initials: JP
authors.lastname: van Wijngaarden
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: N L
authors.initials: NL
authors.lastname: van der Zwaluw
authors.affiliation: Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Centre, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Sohl
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: P H
authors.initials: PH
authors.lastname: In't Veld
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: S C
authors.initials: SC
authors.lastname: van Dijk
authors.affiliation: Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Centre, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
authors.forename: K M A
authors.initials: KM
authors.lastname: Swart
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: A W
authors.initials: AW
authors.lastname: Enneman
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: A C
authors.initials: AC
authors.lastname: Ham
authors.affiliation: Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Centre, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
authors.forename: N M
authors.initials: NM
authors.lastname: van Schoor
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.|Department of Internal Medicine, Section of Geriatrics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: van der Velde
authors.affiliation: Department of Internal Medicine, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA, Rotterdam, The Netherlands.
authors.forename: A G
authors.initials: AG
authors.lastname: Uitterlinden
authors.affiliation: Department of Internal Medicine, Endocrine Section, VU University Medical Center, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
authors.forename: P
authors.initials: P
authors.lastname: Lips
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: E J M
authors.initials: EJ
authors.lastname: Feskens
authors.affiliation: Division of Human Nutrition, Wageningen University, P.O. Box 8129, 6700 EV, Wageningen, The Netherlands.
authors.forename: L C P G M
authors.initials: LC
authors.lastname: de Groot
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003863:Depression / Q000097:blood* / Q000150:complications; D019587:Dietary Supplements; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D009426:Netherlands; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000150:complications
chemical_list: D014807:Vitamin D
keywords: Depression; Diabetes; Elderly; Vitamin D; Vitamin D receptor polymorphisms