Relationship of vitamin D status with lung function and exercise capacity in COPD

Respirology. 2015 Jul;20(5):782-9. doi: 10.1111/resp.12538. Epub 2015 Apr 13.

Abstract

Background and objective: The relationship between blood vitamin D level and clinical parameters in patients with chronic obstructive pulmonary disease (COPD) has been reported with conflicting results. We explored the effects of vitamin D on clinical characteristics of patients with COPD in Korea.

Methods: The study population comprised 193 patients with COPD from Korean Obstructive Lung Disease Cohort. The plasma level of 25-OH vitamin D3 (25-OH-VitD3) was measured every year along with various clinical parameters such as lung function, 6-min walking (6MW) distance, quality of life, exacerbations and emphysema index. Generalized estimating equations and linear mixed model were used for statistical analysis.

Results: Of the 193 patients, 12 (6.2%), 28 (14.5%) and 153 (79.3%) were categorized into normal, insufficiency and deficiency groups. Clustered analysis showed that the plasma 25-OH-VitD3 level was associated with the post-bronchodilator ratio of force expiratory volume in 1 s/forced vital capacity (FEV1 /FVC) (estimated = 0.001; P = 0.022). The vitamin D deficiency group showed lower FEV1 (estimated = -0.129, P = 0.043), FEV1 % predicted (estimated = -4.994, P = 0.029) and FEV1 /FVC ratio (estimated = -0.048, P = 0.001) than did the non-deficiency group. The 6MW distance tended to be shorter in deficiency group (estimated = -17.26, P = 0.069) than in non-deficiency group. Quality of life, exacerbation and emphysema index were not associated with plasma 25-OH-VitD3 level.

Conclusions: We demonstrated a high prevalence of vitamin D deficiency in Korean patients with COPD and a significant relationship between vitamin D deficiency and airflow limitation. The exercise capacity tended to be decreased in the vitamin D deficiency group.

Keywords: chronic obstructive pulmonary disease; exacerbation; exercise; lung function; vitamin D.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Calcifediol* / blood
  • Calcifediol* / deficiency
  • Cohort Studies
  • Exercise Tolerance / physiology*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prevalence
  • Pulmonary Disease, Chronic Obstructive* / blood
  • Pulmonary Disease, Chronic Obstructive* / diagnosis
  • Pulmonary Disease, Chronic Obstructive* / epidemiology
  • Pulmonary Disease, Chronic Obstructive* / physiopathology
  • Pulmonary Disease, Chronic Obstructive* / psychology
  • Pulmonary Emphysema / physiopathology
  • Quality of Life*
  • Republic of Korea / epidemiology
  • Respiratory Function Tests / methods
  • Vitamin D Deficiency* / blood
  • Vitamin D Deficiency* / epidemiology

Substances

  • Calcifediol