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Thorax 65:215-220 doi:10.1136/thx.2009.120659
  • Chronic obstructive pulmonary disease

Vitamin D deficiency is highly prevalent in COPD and correlates with variants in the vitamin D-binding gene

  1. Diether Lambrechts3
  1. 1Respiratory Division, University Hospital Gasthuisberg, Katholieke Universiteit Leuven, Belgium
  2. 2Clinic and Laboratory of Experimental Medicine and Endocrinology, Katholieke Universiteit Leuven, Belgium
  3. 3Vesalius Research Center, VIB, Katholieke Universiteit Leuven, Belgium
  4. 4Service of Radiology, University Hospital Gasthuisberg, Katholieke Universiteit Leuven, Belgium
  5. 5Vesalius Research Center, VIB, Belgium
  1. Correspondence to Dr Wim Janssens, Respiratory Division, University Hospital Gasthuisberg, KUL Herestraat 49, 3000 Leuven, Belgium; wim.janssens{at}uz.kuleuven.be
  • Received 29 May 2009
  • Accepted 21 October 2009
  • Published Online First 8 December 2009

Abstract

Introduction Vitamin D deficiency has been associated with many chronic illnesses, but little is known about its relationship with chronic obstructive pulmonary disease (COPD).

Objectives Serum 25-hydroxyvitamin D (25-OHD) levels were measured in 414 (ex)-smokers older than 50 years and the link between vitamin D status and presence of COPD was assessed. The rs7041 and rs4588 variants in the vitamin D-binding gene (GC) were genotyped and their effects on 25-OHD levels were tested.

Results In patients with COPD, 25-OHD levels correlated significantly with forced expiratory volume in 1 s (FEV1) (r=0.28, p<0.0001). Compared with 31% of the smokers with normal lung function, as many as 60% and 77% of patients with GOLD (Global Initiative for Obstructive Lung Disease) stage 3 and 4 exhibited deficient 25-OHD levels <20 ng/ml (p<0.0001). Additionally, 25-OHD levels were reduced by 25% in homozygous carriers of the rs7041 at-risk T allele (p<0.0001). This correlation was found to be independent of COPD severity, smoking history, age, gender, body mass index, corticosteroid intake, seasonal variation and rs4588 (p<0.0001). Notably, 76% and 100% of patients with GOLD stage 3 and 4 homozygous for the rs7041 T allele exhibited 25-OHD levels <20 ng/ml. Logistic regression corrected for age, gender and smoking history further revealed that homozygous carriers of the rs7041 T allele exhibited an increased risk for COPD (OR 2.11; 95% CI 1.20 to 3.71; p=0.009).

Conclusion Vitamin D deficiency occurs frequently in COPD and correlates with severity of COPD. The data warrant vitamin D supplementation in patients with severe COPD, especially in those carrying at-risk rs7041 variants.

Footnotes

  • Funding IWT-Vlaanderen, FWO Vlaanderen.

  • Competing interests None.

  • Ethics approval This study was conducted with the approval of the Local Ethics Committee of the University Hospital Leuven.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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