Xiaochen Li1, Xiansheng Liu2, Yongjian Xu1, Weining Xiong1, Jianping Zhao1, Wang Ni1, Shixin Chen1. 1. Department of Respiratory Diseases, Tongji Hospital, Key Lab of Pulmonary Diseases of Health Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. 2. Department of Respiratory Diseases, Tongji Hospital, Key Lab of Pulmonary Diseases of Health Ministry, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. Email: liuxiansheng69@gmail.com.
Abstract
OBJECTIVE: To assess the correlation of serum 25-hydroxyvitamin D (25-OHD) levels with vitamin D-binding protein (the group-specific component, GC) gene polymorphism in chronic obstructive pulmonary disease (COPD). METHODS: In a cross-sectional case-control study, 250 participants, including 116 COPD patients with smoking history and 134 healthy smokers, were investigated. A questionnaire about smoking history, vitamin D intake and comorbidities was collected. General pulmonary function was done by routine. Serum 25-OHD levels were detected by ELISA. The genetic variants (rs4588 and rs7041) were genotyped by real time fluorescence polymerase chain reaction (RT-PCR) with TaqMan probe technology. RESULTS: The COPD patients had lower serum vitamin D level than the smoker subjects (36.58 nmol/L vs 43.80 nmol/L, P < 0.001). In the COPD patients, vitamin D level was 39.43 nmol/L in those with percentage of predicted forced expiratory volume in 1 second (FEV1%pred) greater than or equal to 80%.In other groups with FEV1%pred 50%-80%, 30%-50% and lower than 30%, vitamin D levels were 35.32 nmol/L, 32.21 nmol/L, 26.25 nmol/L respectively (P < 0.01). Moreover, there was a significant relevance of 25-OHD levels with FEV1%pred in both COPD patients and healthy smokers (r(2) = 1.911; P < 0.000 1). The mean 25-OHD concentration had a negative correlation with Global Initiative for Obstructive Lung Disease (GOLD) stages. Homozygous carriers of vitamin D-binding protein gene rs7041 T allele were independently related to 25-OHD levels and susceptibility of COPD (P < 0.01; OR = 2.140, 95%CI 1.157-3.959, P = 0.015 respectively). CONCLUSIONS: Patients with COPD are at high risk of vitamin D deficiency and the severity of COPD is inversely correlated with vitamin D levels. Furthermore, homozygous carrier of rs7041 T allele influences 25-OHD serum levels and is related to susceptibility of COPD, which may be a potential candidate gene for screening COPD.
OBJECTIVE: To assess the correlation of serum 25-hydroxyvitamin D (25-OHD) levels with vitamin D-binding protein (the group-specific component, GC) gene polymorphism in chronic obstructive pulmonary disease (COPD). METHODS: In a cross-sectional case-control study, 250 participants, including 116 COPD patients with smoking history and 134 healthy smokers, were investigated. A questionnaire about smoking history, vitamin D intake and comorbidities was collected. General pulmonary function was done by routine. Serum 25-OHD levels were detected by ELISA. The genetic variants (rs4588 and rs7041) were genotyped by real time fluorescence polymerase chain reaction (RT-PCR) with TaqMan probe technology. RESULTS: The COPD patients had lower serum vitamin D level than the smoker subjects (36.58 nmol/L vs 43.80 nmol/L, P < 0.001). In the COPD patients, vitamin D level was 39.43 nmol/L in those with percentage of predicted forced expiratory volume in 1 second (FEV1%pred) greater than or equal to 80%.In other groups with FEV1%pred 50%-80%, 30%-50% and lower than 30%, vitamin D levels were 35.32 nmol/L, 32.21 nmol/L, 26.25 nmol/L respectively (P < 0.01). Moreover, there was a significant relevance of 25-OHD levels with FEV1%pred in both COPD patients and healthy smokers (r(2) = 1.911; P < 0.000 1). The mean 25-OHD concentration had a negative correlation with Global Initiative for Obstructive Lung Disease (GOLD) stages. Homozygous carriers of vitamin D-binding protein gene rs7041 T allele were independently related to 25-OHD levels and susceptibility of COPD (P < 0.01; OR = 2.140, 95%CI 1.157-3.959, P = 0.015 respectively). CONCLUSIONS:Patients with COPD are at high risk of vitamin D deficiency and the severity of COPD is inversely correlated with vitamin D levels. Furthermore, homozygous carrier of rs7041 T allele influences 25-OHD serum levels and is related to susceptibility of COPD, which may be a potential candidate gene for screening COPD.