title: Vitamin D levels are low in adult patients with sickle cell disease in Jamaica and West Africa.
abstract: BACKGROUND
  Patients with sickle cell disease in the USA have been noted to have lower levels of vitamin D - measured as 25-hydroxyvitamin D (25(OH)D) - compared to controls. Average serum 25(OH)D levels are also substantially lower in African Americans than whites, while population distributions of 25(OH)D among Jamaicans of African descent and West Africans are the same as among USA whites. The purpose of this study was to examine whether adult patients with sickle cell disease living in tropical regions had reduced 25(OH)D relative to the general population.
  
  
  METHODS
  We analyzed serum 25(OH)D in stored samples collected from studies in Jamaica and West Africa of adult patients with sickle cell disease and adult population controls.
  
  
  RESULTS
  In samples of 20 Jamaicans and 50 West Africans with sickle cell disease mean values of 25(OH)D were 37% and 39% lower than controls, respectively. Metabolic abnormalities in the absorption and conversion pathways are possible causes for the consistent relative deficiency of 25(OH)D in sickle cell disease.
  
  
  CONCLUSIONS
  Low 25(OH)D levels in tropical Africa where the burden of sickle cell disease is highest, deserve further investigation, and a randomized trial is warranted to address efficacy of supplementation.
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, 2160 S. First Ave, Maywood, IL 60153 USA.
authors.forename: Bamidele O
authors.initials: BO
authors.lastname: Tayo
authors.affiliation: Department of Hematology, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Titilola S
authors.initials: TS
authors.lastname: Akingbola
authors.affiliation: Department of Medicine, College of Medicine, University of Ibadan, Ibadan, Nigeria.
authors.forename: Babatunde L
authors.initials: BL
authors.lastname: Salako
authors.affiliation: Sickle Cell Unit, Tropical Medicine Research Institute, The University of the West Indies, Kingston, Jamaica.
authors.forename: Colin A
authors.initials: CA
authors.lastname: McKenzie
authors.affiliation: Sickle Cell Unit, Tropical Medicine Research Institute, The University of the West Indies, Kingston, Jamaica.
authors.forename: Marvin
authors.initials: M
authors.lastname: Reid
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, 2160 S. First Ave, Maywood, IL 60153 USA ; Department of Medicine, Section of Infectious Diseases, Loyola University Chicago Stritch School of Medicine, Maywood, IL USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Layden
authors.affiliation: Aflac Center for Cancer and Blood Disorders Service Comprehensive Sickle Cell Program of Children's Healthcare of Atlanta, Atlanta, GA USA.
authors.forename: Ifeyinwa
authors.initials: I
authors.lastname: Osunkwo
authors.affiliation: Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
authors.forename: Jacob
authors.initials: J
authors.lastname: Plange-Rhule
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, 2160 S. First Ave, Maywood, IL 60153 USA.
authors.forename: Amy
authors.initials: A
authors.lastname: Luke
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, 2160 S. First Ave, Maywood, IL 60153 USA.
authors.forename: Ramon
authors.initials: R
authors.lastname: Durazo-Arvizu
authors.affiliation: Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, 2160 S. First Ave, Maywood, IL 60153 USA.
authors.forename: Richard S
authors.initials: RS
authors.lastname: Cooper
keywords: 25-hydroxyvitamin D; Adult patients; Jamaica; Sickle cell anemia; Sickle cell disease; Tropical Africa; Vitamin D; West Africa