title: Vitamin D status among pulmonary TB patients and non-TB controls: a cross-sectional study from Mwanza, Tanzania.
abstract: BACKGROUND
  Little is known about vitamin D status in low-income populations burdened with infectious diseases. Hence, there is a need for data on correlates of serum 25-hydroxy vitamin D (S-25(OH)D) and its validity during infections.
  
  
  OBJECTIVE
  To assess the role of pulmonary TB (PTB) and HIV as correlates of S-25(OH)D.
  
  
  METHODS
  Age-sex-matched cross-sectional study among PTB patients and non-TB controls.
  
  
  METHODS
  PTB patients were categorized as sputum negative (PTB-) and positive (PTB+) by culture. Non-TB controls were randomly selected among age-sex-matched neighbours to PTB+ patients. Height, weight, arm circumference and triceps skinfold were measured, and body mass index (BMI), arm fat (AFA) and muscle area (AMA) computed. HIV status, and S-25(OH)D, C-reactive protein (S-CRP) and α1-acid glycoprotein (S-AGP) were determined. Linear regression analysis with controls and PTB patients combined was used to identify correlates of S-25(OH)D.
  
  
  RESULTS
  S-25(OH)D data were available on 97.8% (1570) of 1605 participants. Mean (SD) S-25(OH)D was 84.4 (25.6) nmol/L with 39.6% <75 nmol/L among 347 non-TB controls. Time of recruitment, sex, PTB and HIV, and elevated S-AGP were correlates of S-25(OH)D. S-25(OH)D was 24.8 (95% CI 18.6;30.9) nmol/L higher in PTB compared to controls among females, but only 9.8 (95% CI:4.5;15.2) nmol/L among males (interaction p<0.0001). Females had 13.8 (95% CI:8.2;21.9) nmol/L lower S-25(OH)D than males, and HIV infected individuals had 8.5 (95% CI:4.9;12.1) higher S-25(OH)D compared to uninfected. Elevated S-AGP was a positive correlate of S-25(OH)D. Low BMI was associated with S-25(OH)D, but not with infections or S-AGP in the model.
  
  
  CONCLUSIONS
  While S-25(OH)D may decline transiently during a mild acute phase response, it may increase if the acute phase response leads to loss of fat. The validity of S-25(OH)D as a marker of vitamin D status may be affected by infections.
authors: Department of Nutrition, Sports and Exercise, University of Copenhagen, Frederiksberg, Denmark.
authors: Henrik
authors: H
authors: Friis
authors: Nyagosya
authors: N
authors: Range
authors: John
authors: J
authors: Changalucha
authors: George
authors: G
authors: Praygod
authors: Kidola
authors: K
authors: Jeremiah
authors: Daniel
authors: D
authors: Faurholt-Jepsen
authors: Henrik
authors: H
authors: Krarup
authors: Christian
authors: C
authors: Mølgaard
authors: Åse  Bengaard
authors: Å
authors: Andersen
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001835:Body Weight; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D060085:Coinfection; D003430:Cross-Sectional Studies; D005260:Female; D006678:HIV; D015658:HIV Infections / Q000097:blood* / Q000821:virology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D009752:Nutritional Status; D012044:Regression Analysis; D013183:Sputum / Q000382:microbiology; D013636:Tanzania; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000382:microbiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; D002097:C-Reactive Protein; C104450:25-hydroxyvitamin D