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Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial.

Publication ,  Journal Article
Smith, LJ; Kalhan, R; Wise, RA; Sugar, EA; Lima, JJ; Irvin, CG; Dozor, AJ; Holbrook, JT; American Lung Association Asthma Clinical Research Centers
Published in: JAMA
May 26, 2015

IMPORTANCE: Soy isoflavone supplements are used to treat several chronic diseases, although the data supporting their use are limited. Some data suggest that supplementation with soy isoflavone may be an effective treatment for patients with poor asthma control. OBJECTIVE: To determine whether a soy isoflavone supplement improves asthma control in adolescent and adult patients with poorly controlled disease. DESIGN, SETTING, AND PARTICIPANTS: Multicenter, randomized, double-blind, placebo-controlled trial conducted between May 2010 and August 2012 at 19 adult and pediatric pulmonary and allergy centers in the American Lung Association Asthma Clinical Research Centers network. Three hundred eighty-six adults and children aged 12 years or older with symptomatic asthma while taking a controller medicine and low dietary soy intake were randomized, and 345 (89%) completed spirometry at week 24. INTERVENTIONS: Participants were randomly assigned to receive soy isoflavone supplement containing 100 mg of total isoflavones (n=193) or matching placebo (n=193) in 2 divided doses administered daily for 24 weeks. MAIN OUTCOMES AND MEASURES: The primary outcome measure was change in forced expiratory volume in the first second (FEV1) at 24 weeks. Secondary outcome measures were symptoms, episodes of poor asthma control, Asthma Control Test score (range, 5-25; higher scores indicate better control), and systemic and airway biomarkers of inflammation. RESULTS: Mean changes in prebronchodilator FEV1 over 24 weeks were 0.03 L (95% CI, -0.01 to 0.08 L) in the placebo group and 0.01 L (95% CI, -0.07 to 0.07 L) in the soy isoflavone group, which were not significantly different (P = .36). Mean changes in symptom scores on the Asthma Control Test (placebo, 1.98 [95% CI, 1.42-2.54] vs soy isoflavones, 2.20 [95% CI, 1.53-2.87]; positive values indicate a reduction in symptoms), number of episodes of poor asthma control (placebo, 3.3 [95% CI, 2.7-4.1] vs soy isoflavones, 3.0 [95% CI, 2.4-3.7]), and changes in exhaled nitric oxide (placebo, -3.48 ppb [95% CI, -5.99 to -0.97 ppb] vs soy isoflavones, 1.39 ppb [95% CI, -1.73 to 4.51 ppb]) did not significantly improve more with the soy isoflavone supplement than with placebo. Mean plasma genistein level increased from 4.87 ng/mL to 37.67 ng/mL (P < .001) in participants receiving the supplement. CONCLUSIONS AND RELEVANCE: Among adults and children aged 12 years or older with poorly controlled asthma while taking a controller medication, use of a soy isoflavone supplement, compared with placebo, did not result in improved lung function or clinical outcomes. These findings suggest that this supplement should not be used for patients with poorly controlled asthma. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01052116.

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Published In

JAMA

DOI

EISSN

1538-3598

Publication Date

May 26, 2015

Volume

313

Issue

20

Start / End Page

2033 / 2043

Location

United States

Related Subject Headings

  • Young Adult
  • Soybean Proteins
  • Plant Extracts
  • Phytotherapy
  • Middle Aged
  • Male
  • Lung
  • Isoflavones
  • Humans
  • Genistein
 

Citation

APA
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Smith, L. J., Kalhan, R., Wise, R. A., Sugar, E. A., Lima, J. J., Irvin, C. G., … American Lung Association Asthma Clinical Research Centers. (2015). Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial. JAMA, 313(20), 2033–2043. https://doi.org/10.1001/jama.2015.5024
Smith, Lewis J., Ravi Kalhan, Robert A. Wise, Elizabeth A. Sugar, John J. Lima, Charles G. Irvin, Allen J. Dozor, Janet T. Holbrook, and American Lung Association Asthma Clinical Research Centers. “Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial.JAMA 313, no. 20 (May 26, 2015): 2033–43. https://doi.org/10.1001/jama.2015.5024.
Smith LJ, Kalhan R, Wise RA, Sugar EA, Lima JJ, Irvin CG, et al. Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial. JAMA. 2015 May 26;313(20):2033–43.
Smith, Lewis J., et al. “Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial.JAMA, vol. 313, no. 20, May 2015, pp. 2033–43. Pubmed, doi:10.1001/jama.2015.5024.
Smith LJ, Kalhan R, Wise RA, Sugar EA, Lima JJ, Irvin CG, Dozor AJ, Holbrook JT, American Lung Association Asthma Clinical Research Centers. Effect of a soy isoflavone supplement on lung function and clinical outcomes in patients with poorly controlled asthma: a randomized clinical trial. JAMA. 2015 May 26;313(20):2033–2043.
Journal cover image

Published In

JAMA

DOI

EISSN

1538-3598

Publication Date

May 26, 2015

Volume

313

Issue

20

Start / End Page

2033 / 2043

Location

United States

Related Subject Headings

  • Young Adult
  • Soybean Proteins
  • Plant Extracts
  • Phytotherapy
  • Middle Aged
  • Male
  • Lung
  • Isoflavones
  • Humans
  • Genistein