Vitamin D Deficiency Is Associated with Decreased Lung Function in Chinese Adults with Asthma

Harvard University, Cambridge, Massachusetts, United States
Respiration (Impact Factor: 2.59). 12/2010; 81(6):469-75. DOI: 10.1159/000322008
Source: PubMed


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.
To examine whether vitamin D status is associated with lung function and total serum IgE in Chinese adults with newly diagnosed asthma.
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.
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.
Vitamin D deficiency was highly prevalent in Chinese asthma patients, and vitamin D status was associated with lung function.

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    • "Some studies showed that role of vitamin D was wider [7] [8] [9]. This nutrient may participate in pathogenesis of oncological, endocrine, cardiovascular, psychiatric, autoimmune and allergic diseases including asthma [10] [11] [12] [13] [14]. The role of vitamin D in asthma may be explained by its impact on T cell [3] [4] [12] [15]. "
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    ABSTRACT: Background and objective: Some researches show that low vitamin D may play a role in asthma pathogenesis. The aim of this study was to evaluate the serum vitamin D level in asthmatics with different phenotypes and to determine its associations with lung function, IgE, eosinophil count and body mass index (BMI). Materials and methods: The study population comprised 85 patients with asthma and 73 healthy persons. Patients with asthma were divided into groups according to phenotypes. Allergy was assessed using a skin prick test and measuring eosinophil count in peripheral blood and total IgE in serum. Lung function was evaluated by spirometry. Concentration of vitamin D (25(OH)D3) was measured using a commercial ELISA kit. Smoking history was assessed and BMI was calculated for all individuals. Results: The vitamin D level was lower in asthmatics than in the control group (14.36. ±. 0.57 vs. 22.13. ±. 0.84. ng/mL, P <. 0.01). There were no significant differences in the vitamin D level between the groups with allergic and non-allergic asthma (14.36. ±. 0.77 vs. 14.35. ±. 0.74. ng/mL). The low vitamin D level increased the risk of asthma 1.2 times (OR, 1.194; 95% CI, 1.109-1.286, P <. 0.01). The vitamin D level did not correlate with lung function and markers of allergy in asthmatic patients. The vitamin D level correlated with FEV1/FVC (rs = 0.72, P <. 0.05) in smoking patients with asthma. Correlation between the vitamin D level and BMI was found in all studied subjects (rs = -0.18, P <. 0.05). Conclusions: The vitamin D level was lower in asthmatic patients than in healthy individuals despite their hypersensitivity and increase risk of asthma. There was no relation between the vitamin D level and lung function, eosinophil count and total IgE level, whereas the lower vitamin D level was associated with higher BMI.
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    • "The findings of a cross-sectional study including Chinese patients with newly diagnosed asthma concluded that vitamin D deficiency was highly prevalent and was associated with decreased lung function in this population.101 Also, in asthmatic adult patients, reduced vitamin D levels were associated with impaired lung function, increased airway hyperresponsiveness, and reduced glucocorticoid response, suggesting that supplementation of vitamin D levels in these patients might improve multiple parameters of asthma severity and treatment response.9 "
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    ABSTRACT: Humans have the ability to synthesize vitamin D during the action of ultraviolet (UV) radiation upon the skin. Apart from the regulation of calcium and phosphate metabolism, another critical role for vitamin D in immunity and respiratory health has been revealed, since vitamin D receptors have also been found in other body cells. The term "vitamin D insufficiency" has been used to describe low levels of serum 25-hydroxyvitamin D that may be associated with a wide range of pulmonary diseases, including viral and bacterial respiratory infection, asthma, chronic obstructive pulmonary disease, and cancer. This review focuses on the controversial relationship between vitamin D and asthma. Also, it has been found that different gene polymorphisms of the vitamin D receptor have variable associations with asthma. Other studies investigated the vitamin D receptor signaling pathway in vitro or in experimental animal models and showed either a beneficial or a negative effect of vitamin D in asthma. Furthermore, a range of epidemiological studies has also suggested that vitamin D insufficiency is associated with low lung function. In the future, clinical trials in different asthmatic groups, such as infants, children of school age, and ethnic minorities are needed to establish the role of vitamin D supplementation to prevent and/or treat asthma.
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    • "This percentage (90%) is higher than that reported in another study of Costa Rican asthmatic children, in which 28% had vitamin D insufficiency,7 and much higher than the 20% reported by Alyasin et al.15 in Iranian children. However, this high percentage is similar to that reported by Li et al.16 in asthmatic adults from China and is consistent with the epidemics of hypovitaminosis D in developing countries reported by Arabi et al.17 "
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    ABSTRACT: Non-classical actions of vitamin D as a cytokine are related to the immunopathology of asthma. Few studies have examined vitamin D levels and asthma severity in adults. The aim of this research was to assess the relationship between vitamin D levels, atopy markers, pulmonary function, and asthma severity. We analyzed 25-hydroxyvitamin D levels in serum collected from 121 asthmatic adults from Costa Rica to investigate the association between vitamin D levels (categorized as sufficient, ≥30 ng/mL, or insufficient, <30 ng/mL), allergic rhinitis, total IgE and peripheral blood eosinophils (as markers of atopy), asthma severity, baseline forced expiratory volume in 1 second (FEV1), and forced vital capacity (FVC). Univariate and multivariate analyses were performed to assess these relationships. When the population was stratified by vitamin D status, 91% of asthmatic patients with vitamin D levels below 20 ng/mL (n=36) and 74% of patients with vitamin D levels between 20 and 30 ng/mL (n=73) had severe asthma versus 50% of those with vitamin D sufficiency (n=12; P=0.02). Vitamin D insufficiency was associated with a higher risk of severe asthma (odds ratio [OR], 5.04; 95% Confidence interval [CI], 1.23-20.72; P=0.02). High vitamin D levels were associated with a lower risk of hospitalization or emergency department visit during the last year (OR, 0.90; 95% CI, 0.84-0.98; P=0.04). Although there appeared to be a direct relationship between vitamin D levels and FEV1 (regression coefficient=0.48; r(2)=0.03), it did not reach statistical significance (P=0.07). Our findings suggest that vitamin D insufficiency is common among our cohort of asthmatic adults. Lower vitamin D levels are associated with asthma severity.
    Full-text · Article · Sep 2013 · Allergy, asthma & immunology research
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