Vitamin D deficiency is associated with decreased lung function in Chinese adults with asthma.
BACKGROUND
Vitamin D deficiency has been associated with markers for allergy and asthma severity in children with asthma. However, its association with Chinese adult asthmatics has not been studied.


OBJECTIVE
To examine whether vitamin D status is associated with lung function and total serum IgE in Chinese adults with newly diagnosed asthma.


METHODS
We conducted a cross-sectional study including 435 Chinese patients aged >18 years with newly diagnosed asthma. Vitamin D status was assessed by measuring serum 25 hydroxyvitamin D (25OHD) concentrations. The primary outcomes included airflow limitation, as measured by the forced expiratory volume in 1 s (FEV(1)), FEV(1) % predicted, and FEV(1)/forced vital capacity (FVC), and serum total IgE concentration.


RESULTS
Vitamin D deficiency was prevalent in Chinese adults with asthma, with 88.9% of the subjects having 25OHD <50 nmol/l. Serum 25OHD concentration was positively correlated with FEV(1) % predicted (p = 0.02, r = 0.12). After adjusting for age, sex, body mass index, smoking, month of blood collection, and symptom duration, we found significant positive associations between 25OHD concentrations and FEV(1) (in liters), FEV(1) % predicted, and FEV(1)/FVC (p for trend < 0.05 for all). The adjusted odds ratios for the highest versus the lowest 25OHD quartile were 0.50 (0.26-0.96) for FEV(1) <75% predicted and 0.44 (0.20-0.95) for FEV(1)/FVC% <0.75. There was no significant association between 25OHD concentrations and total IgE.


CONCLUSIONS
Vitamin D deficiency was highly prevalent in Chinese asthma patients, and vitamin D status was associated with lung function.
Department of Respiratory Diseases, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
Fei
F
Li
Min
M
Peng
Lei
L
Jiang
Qi
Q
Sun
Kui
K
Zhang
Fuzhi
F
Lian
Augusto A
AA
Litonjua
Jinming
J
Gao
Xiang
X
Gao
D000328:Adult; D001249:Asthma / Q000097:blood / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004804:Eosinophils; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D014797:Vital Capacity; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology
D015415:Biomarkers; D014807:Vitamin D; D007073:Immunoglobulin E