背景：流行病学数据显示，低镁饮食与哮喘的发病和进展相关。   
    目的：在轻中度哮喘患者中研究长期（6.5个月）口服补镁是否有助于改善哮喘控制，增加血清中的镁含量。
    研究对象：根据全美心肺和血液研究所（NHLBI）和哮喘教育和预防项目（NAEPP）指南，选取55名年龄21～55岁患轻度至中度哮喘的患者，这些患者仅采用β受体激动剂或吸入糖皮质激素治疗哮喘。
    设计：患者随机接受340 mg（170 mg每天2次）镁制剂或安慰剂治疗6.5个月。
    检测指标：检测血清、红细胞、尿液、饮食中的镁含量，以及离子镁和IV镁含量，明确体内的含镁状态。
    目的：哮喘控制标志物为：乙酰甲胆碱激发试验（MCCT）和肺功能检测（PFT）。采用哮喘生活质量（AQLQ）和哮喘控制（ACQ）进行主观有效问卷调查。检测炎症标志物，包括C反应蛋白（CRP）、呼出气一氧化氮含量（eNO）。
    结果：口服镁制剂6个月后，导致用力第1秒呼气体积（FEV1）下降20％的乙酰甲胆碱浓度显著增加。口服镁的哮喘患者，峰值流速（PEFR）预测值改善5.8％（P = 0.03）。口服镁6.5个月后，AQLQ平均评分（P < 0.01）和总体ACQ评分（P = 0.05）显著改善。尽管存在上述改善，但有关显示镁状态的指标在两组间未见显著差异。
    结论：对成人哮喘患者，口服镁剂后乙酰甲胆碱支气管反应性及PEFR均明显改善，哮喘控制水平及生活质量也得到明显改善。

Effect of oral magnesium supplementation on measures of airway resistance and subjective assessment of asthma control and quality of life in men and women with mild to moderate asthma: a randomized placebo controlled trial.

Kazaks AG, Uriu-Adams JY, Albertson TE, Shenoy SF, Stern JS.

Department of Nutrition and Exercise Science, Bastyr University, Kenmore, Washington 98028-4966, USA. akazaks@bastyr.edu

BACKGROUND: Epidemiological data shows low dietary magnesium(Mg) may be related to incidence and progression of asthma.

OBJECTIVE: To determine if long term(6.5 month) treatment with oral Mg would improve asthma control and increase serum measures of Mg status in men and women with mild-to-moderate asthma.

SUBJECTS: 55 males and females aged 21 to 55 years with mild to moderate asthma according to the 2002 National Heart, Lung, and Blood Institute (NHLBI) and Asthma Education and Prevention Program(NAEPP) guidelines and who used only beta-agonists or inhaled corticosteroids(ICS) as asthma medications were enrolled.

DESIGN: Subjects were randomly assigned to consume 340 mg(170 mg twice a day) of Mg or a placebo for 6.5 months.

MEASUREMENTS: Multiple measures of Mg status including serum, erythrocyte, urine, dietary, ionized and IV Mg were measured.

OBJECTIVE: markers of asthma control were: methacholine challenge test(MCCT) and pulmonary function test(PFT) results. Subjective validated questionnaires on asthma quality of life(AQLQ) and control(ACQ) were completed by participants. Markers of inflammation, including c-reactive protein(CRP) and exhaled nitric oxide(eNO) were determined.

RESULTS: The concentration of methacholine required to cause a 20% drop in forced expiratory volume in in minute(FEV(1)) increased significantly from baseline to month 6 within the Mg group. Peak expiratory flow rate(PEFR) showed a 5.8% predicted improvement over time(P = 0.03) in those consuming the Mg. There was significant improvement in AQLQ mean score units(P < 0.01) and in overall ACQ score only in the Mg group(P = 0.05) after 6.5 months of supplementation. Despite these improvements, there were no significant changes in any of the markers of Mg status.

CONCLUSION: Adults who received oral Mg supplements showed improvement in objective measures of bronchial reactivity to methacholine and PEFR and in subjective measures of asthma control and quality of life.