Vitamin-D deficiency is associated with chronic bacterial colonisation and disease severity in bronchiectasis.
BACKGROUND
Vitamin-D deficiency has been linked to an increased risk of respiratory infections. The objective of this study was to determine the frequency and clinical importance of vitamin-D deficiency in patients with bronchiectasis.


METHODS
25-hydroxyvitamin-D was measured by immunoassay in 402 stable patients with bronchiectasis. Patients were classified as vitamin-D deficient (serum 25-hydroxyvitamin-D <25 nmol/l), insufficient (25 nmol/l-74 nmol/l) or sufficient (≥ 75 nmol/l). Disease severity was assessed, including exacerbation frequency, measurement of airway inflammatory markers, sputum bacteriology and lung function over 3 years follow-up.


RESULTS
50% of bronchiectasis patients were vitamin-D deficient, 43% insufficient and only 7% sufficient. This compared to only 12% of age and sex matched controls with vitamin-D deficiency (p<0.0001). Vitamin-D deficient patients were more frequently chronically colonised with bacteria (p<0.0001), 21.4% of vitamin-D deficient subjects were colonised with Pseudomonas aeruginosa compared to 10.4% of insufficient patients and 3.6% of sufficient patients, p=0.003. Vitamin-D deficient patients had lower FEV(1)% predicted (p=0.002), and more frequent pulmonary exacerbations (p=0.04). Vitamin-D deficient patients had higher sputum levels of inflammatory markers and demonstrated a more rapid decline in lung function over 3 years follow-up. Defects in neutrophil function and assessment of airway LL-37 levels did not provide a mechanistic explanation for these findings. Vitamin-D deficient patients had, however, higher levels of Vitamin-D Binding Protein in sputum sol.


CONCLUSIONS
Vitamin-D deficiency is common in bronchiectasis and correlates with markers of disease severity. The mechanism of this association is unclear.
The University of Edinburgh/MRC Centre for Research Inflammation, The Queen's Medical Research Institute, Edinburgh, UK. jamesdchalmers@googlemail.com
James D
JD
Chalmers
Brian J
BJ
McHugh
Catherine
C
Docherty
John R W
JR
Govan
Adam T
AT
Hill
D000368:Aged; D001987:Bronchiectasis / Q000453:epidemiology* / Q000382:microbiology* / Q000503:physiopathology; D016022:Case-Control Studies; D002908:Chronic Disease; D015331:Cohort Studies; D015169:Colony Count, Microbial; D015897:Comorbidity; D005260:Female; D006090:Gram-Negative Bacteria / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012016:Reference Values; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000503:physiopathology; D018570:Risk Assessment; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology; D006113:United Kingdom / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*
D014807:Vitamin D; C104450:25-hydroxyvitamin D