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Soy isoflavone consumption has been associated with improved lung function in some patients with asthma. Smith and colleagues investigated this relationship in 386 adults and children aged 12 years or older with poorly controlled asthma who were randomly assigned to receive a daily soy isoflavone supplement or placebo for 24 weeks. The authors report that compared with placebo, use of the soy isoflavone supplement did not result in improved lung function or clinical outcomes, including asthma symptoms, episodes of poor asthma control, or markers of systemic or airway inflammation.
Continuing Medical Education
Copy number variants (CNVs)—genetic sequences that differ in number of copies in the human genome—contribute to interindividual variation in a variety of traits, including intellectual disability. Männik and colleagues performed CNV analysis on a random sample of 7877 Estonian individuals participating in a population biobank to examine the clinical features of unselected adult carriers of known pathological CNVs and to assess the burden of intermediate-sized CNVs on educational attainment and intellectual disability. Among the authors’ findings was that individually rare but collectively common intermediate-sized CNVs may be negatively associated with educational attainment. In an Editorial, Lupski discusses potential clinical implications of the study findings.
Editorial and Continuing Medical Education
Overt hyperthyroidism is an established risk factor for osteoporosis and fractures. In a meta-analysis of individual-participant data from 13 prospective cohort studies (70 298 total participants), Blum and colleagues found that subclinical hyperthyroidism was associated with an increased risk of hip and other fractures, particularly among individuals with a thyrotropin level of less than 0.10 mIU/L and those with endogenous subclinical hyperthyroidism.
Author Video Interview
Randomized trials have demonstrated that among men with early-stage, low-risk prostate cancer, observation yields similar survival and decreased morbidity compared with up-front treatment. A recent article in JAMA Internal Medicine reported that in a cohort of 12 068 men with low-risk prostate cancer diagnosed from 2006 through 2009, 80.1% of the men underwent treatment within 12 months of diagnosis. Rates of observation varied widely across urologists, ranging from 4.5% to 64.2% of patients. In this From The JAMA Network article, Ghani and Miller discuss patient- and physician-related factors that influence treatment decisions. The authors highlight strategies—such as patient decision aids and regional physician collaboration with implementation of appropriate use criteria—that may ultimately reduce unwarranted variation in prostate cancer care.
The cluster randomized trial—in which study participants are randomized in groups or clusters to either an experimental intervention or a control condition—is one approach to evaluating the efficacy of treatments that involve changes at the level of the health care practice, hospital unit, or health care system. In this JAMA Guide to Statistics and Methods article, Meurer and Lewis discuss when it is appropriate to use cluster randomization; important limitations and challenges associated with this design; statistical methods for analyzing clustered data; and considerations when evaluating findings from a cluster randomized trial.
This JAMA Clinical Evidence Synopsis article by Blessberger and colleagues summarizes a Cochrane review of 89 randomized trials that assessed the relationship of β-blocker use with mortality and morbidity after cardiac or noncardiac surgery. Among the findings was that β-blocker use is associated with a lower incidence of supraventricular tachycardia and ventricular arrhythmia in cardiac surgery patients. In noncardiac surgery, β-blockers are associated with a possible increase in mortality and strokes, an increase in bradycardia and hypotension, and a lower incidence of acute myocardial infarction and supraventricular tachycardia.
Highlights. JAMA. 2015;313(20):2014. doi:10.1001/jama.2014.11763