Abstract
BACKGROUND: Dietary supplement use is increasing despite lack of evidence of benefits, or evidence of harm. Press releases issued by the supplements industry might contribute to this situation by using 'spin' (strategies to hype or denigrate findings) to distort the results of clinical studies. We assessed press releases issued in response to publication of clinical studies on dietary supplements. METHODS AND FINDINGS: We analyzed 47 supplements industry press releases and 91 non-industry press releases and news stories, generated in response to 46 clinical studies of dietary supplements published between 1/1/2005 and 5/31/2013. The primary outcome was 'spin' content and direction. We also assessed disposition towards use of dietary supplements, reporting of study information, and dissemination of industry press releases. More supplements industry press releases (100%) contained 'spin' than non-industry media documents (55%, P<0.001). Hyping 'spin' scores were higher in industry than non-industry media documents for studies reporting benefit of supplements (median 'spin' score 3.3, 95% CI 1.0-5.5 vs 0.5, 0-1.0; P<0.001). Denigratory 'spin' scores were higher in industry than non-industry media documents for studies reporting no effect (6.0, 5.0-7.0 vs 0, 0-0; P<0.001) or harm (6.0, 5.5-7.5 vs 0, 0-0.5; P<0.001) from a supplement. Industry press releases advocated supplement use in response to >90% of studies that reported no benefit, or harm, of the supplement. Industry press releases less frequently reported study outcomes, sample size, and estimates of effect size than non-industry media documents (all P<0.001), particularly for studies that reported no benefit of supplements. Industry press releases were referenced by 148 news stories on the websites of 6 organizations that inform manufacturers, retailers and consumers of supplements. CONCLUSIONS: Dietary supplements industry press releases issued in response to clinical research findings are characterized by 'spin' that hypes results that are favourable to supplement use and denigrates results that are not.