title: Vitamin D deficiency in urban indigent patients in Southern California.
abstract: OBJECTIVE
  To determine the prevalence of 25-hydroxy (OH) vitamin D deficiency in ambulatory and hospitalized patients from a large urban county medical center in Southern California, and assess the effects of season, ethnicity, age, location of care, and comorbidities on prevalence.
  
  
  METHODS
  Data for all serum 25(OH)-D2 and -D3 concentrations measured during 2010, along with associated demographic characteristics and comorbidity data, were analyzed. 25(OH) D concentrations were measured using liquid chromatography-tandem mass spectrometry.
  
  
  RESULTS
  Of 210,695 patients, serum 25(OH) D concentrations were measured for 3,276 (1.6%), 78% of whom were Hispanic, 69% female, 14% hospitalized, and 86% ambulatory. Median patient age was 54 years. Prevalence of 25(OH) D <10 ng/mL was 6.5% overall, 5.5% in Hispanics, 6.7% in Asians, 15.5% in African Americans, and 8.9% in whites. Prevalence was significantly higher in African Americans than in Hispanics (relative risk (RR): 2.79), males (RR: 2.07), hospitalized patients (RR: 4.96), and winter (RR: 1.34). Prevalence of 25(OH) D <20 ng/mL was 35% overall, 34% in Hispanics, 32% in Asians, 49% in African Americans, and 33% in whites, and was significantly higher in African Americans than Hispanics (RR: 1.45), males (RR: 1.32), hospitalized patients (RR: 2.02), and younger patients (RR: 1.21, age ≤30; 1.16, age 31-50) versus those age 51 to 70 years, and in winter (RR: 1.21).
  
  
  CONCLUSIONS
  Our study estimated the prevalence of 25(OH) D deficiency and identified at-risk patient groups in Southern California; 25(OH) D deficiency should be suspected, diagnosed, and adequately treated to improve the health status in at-risk urban indigent patient populations.
authors: Department of Medicine, Keck School of Medicine at USC and Los Angeles County, University of Southern California Medical Center, Los Angeles, California, USA. ekaptein@usc.edu
authors: Elaine M
authors: EM
authors: Kaptein
authors: San San
authors: SS
authors: Yi
authors: David B
authors: DB
authors: Endres
authors: John S
authors: JS
authors: Kaptein
authors: Linda S
authors: LS
authors: Chan
mesh_terms: D000328:Adult; D000368:Aged; D002140:California / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000208:ethnology
chemical_list: D014807:Vitamin D