最新研究显示，维生素D或能缓解哮喘症状，体内维生素D含量不足的患者，哮喘症状更严重。
研究人员对54名哮喘患者的严重程度及其体内维生素D含量进行了比较。研究发现，相比体内维生素D含量高的哮喘患者，体内维生素D含量低的患者肺功能更差。尤其是在一系列肺功能和气道高反应性测试中，体内维生素D含量低的患者的测试结果更差。肺功能和气道高反应性是哮喘的两个重要特征。研究成果刊登在最新一期《美国呼吸道与危重护理医学杂志》（American Journal of Respiratory and Critical Care）上。
美国丹佛国家犹太医学研究中心呼吸科主任兰德萨瑟兰(Rand Sutherland)在一份声明中指出：“研究表明，维生素D含量低会对一系列哮喘重要特征产生影响，包括肺功能、支气管痉挛、对类固醇的治疗反应等。下一个需要解答的问题是，服用维生素D补充剂是否会改善哮喘患者的临床表现。”
结果发现，相比体内维生素D含量低的患者，体内维生素D含量高的患者的肺功能更强。研究人员表示，维生素D含量高低与参与者在呼吸测试的得分存在直接关系：体内维生素D含量越低，他们的表现越差。例如，体内维生素D含量不足(即低于30毫微克/每毫升)的参与者，气道高反应性表现仅是体内维生素 D含量高的研究参与者的二分之一左右。
这项研究还表明，维生素D含量低与血液中诱发炎症的蛋白含量增加有关，提出了维生素D含量低导致哮喘患者炎症风险增加的可能性。
推荐原始出处：
Am. J. Respir. Crit. Care Med. 2010, doi:10.1164/rccm.200911-1710OC
Vitamin D Levels, Lung Function and Steroid Response in Adult Asthma
E. Rand Sutherland1*, Elena Goleva2, Leisa P. Jackson3, Allen D. Stevens4, and Donald Y.M. Leung2
1 Department of Medicine, National Jewish Health, Denver, Colorado, United States; Department of Medicine, University of Colorado, Denver, Colorado, United States, 2 Department of Pediatrics, National Jewish Health, Denver, Colorado, United States; Department of Pediatrics, University of Colorado, Denver, Colorado, United States, 3 Department of Pediatrics, National Jewish Health, Denver, Colorado, United States, 4 Department of Medicine, National Jewish Health, Denver, Colorado, United States
Rationale: Patients with asthma exhibit variable response to inhaled corticosteroids (ICS). Vitamin D is hypothesized to exert effects on phenotype and glucocorticoid (GC) response in asthma. Objectives: To determine the effect of vitamin D levels on phenotype and glucocorticoid (GC) response in asthma. Methods: Nonsmoking adult asthmatics were enrolled in a study assessing the relationship between serum 25(OH)D (vitamin D) concentrations and lung function, airway hyperresponsiveness (AHR) and GC response as measured by dexamethasone (DEX)-induced expression of MAP kinase phosphatase-1 (MKP-1) by peripheral blood mononuclear cells (PBMCs). Results: 54 adult asthmatics (FEV1 of 82.9±15.7% predicted (mean±SD), serum vitamin D levels of 28.1±10.2 ng/mL) were enrolled. Higher vitamin D levels were associated with greater lung function, with a 21.0±9.2 mL (mean±SE) increase in FEV1 for each ng/mL increase in vitamin D (p=0.03, r=0.8). Participants with vitamin D insufficiency (&30 ng/mL) demonstrated increased AHR, with a PC20 FEV1 of 1.03±0.2 mg/mL versus 1.92±0.2 in those with vitamin D 30 ng/mL (p=0.01). In ICS-untreated participants DEX-induced MKP-1 expression increased with higher vitamin D levels, with a 0.05±0.02-fold increase (p = 0.02, r=0.5) in MKP-1 expression observed for each ng/mL increase in vitamin D, a finding which occurred in the absence of a significant increase in IL-10 expression. Conclusions: In asthma, reduced vitamin D levels are associated with impaired lung function, increased airway hyperresponsiveness and reduced glucocorticoid response, suggesting that supplementation of vitamin D levels in patients with asthma may improve multiple parameters of asthma severity and treatment response.
