Browsing by Subject "Common Cold"

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  • Louhiala, Pekka; Hemilä, Harri (2014)
    In this article, we first take a critical look at the definitions of evidence-based medicine (EBM) and complementary and alternative medicine (CAM). We then explore the question of whether there can be evidence-based forms of CAM. With the help of three examples, we show that EBM and CAM are not opposites, but rather concepts pointing at different dimensions. Each of the three examples is an evidence-based treatment according to three to five randomised, double-blind placebo controlled trials with consistent findings and narrow pooled confidence intervals. The most reasonable interpretation for the existence of evidence-based CAM treatments seems to be that the opposite of CAM is ‘mainstream medicine’, and the demarcation line between CAM and mainstream medicine is not simply defined by the question of whether a treatment works or not. Some effective treatments may belong to the CAM domain for historical reasons and because of preconceptions within mainstream medicine. Therefore, some treatments that currently lie outside mainstream medicine can be evidence-based.
  • Suvinen, Mikko; Toppila-Salmi, Sanna (2016)
  • Hemilä, Harri (2011)
    Proponents of evidence-based medicine (EBM) emphasize that conclusions about medical interventions should be based on controlled trials with clinically relevant outcomes, so that the greatest weight should be given to the systematic reviews of the trials. One of the most comprehensive EBM databases is the Cochrane Library, which contains thousands of systematic reviews on medical interventions. The Cochrane review on vitamin C and the common cold analyzed 29 trial comparisons on the preventive effects of vitamin C, 29 comparisons on the effect of regular vitamin C on common cold duration and severity, and 7 comparisons on the therapeutic effect of vitamin C.1 The review concludes: “Implications for practice: The prophylaxis trials found a reduction in common cold duration of 8% in adults and 13% in children…. So far, therapeutic supplementation has not been shown to be effective. Nevertheless, given the consistent effect of vitamin C on duration and severity in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them.”
  • Hemilä, Harri (2017)
    In the early literature, vitamin C deficiency was associated with pneumonia. After its identification, a number of studies investigated the effects of vitamin C on diverse infections. A total of 148 animal studies indicated that vitamin C may alleviate or prevent infections caused by bacteria, viruses, and protozoa. The most extensively studied human infection is the common cold. Vitamin C administration does not decrease the average incidence of colds in the general population, yet it halved the number of colds in physically active people. Regularly administered vitamin C has shortened the duration of colds, indicating a biological effect. However, the role of vitamin C in common cold treatment is unclear. Two controlled trials found a statistically significant dose-response, for the duration of common cold symptoms, with up to 6-8 g/day of vitamin C. Thus, the negative findings of some therapeutic common cold studies might be explained by the low doses of 3-4 g/day of vitamin C. Three controlled trials found that vitamin C prevented pneumonia. Two controlled trials found a treatment benefit of vitamin C for pneumonia patients. One controlled trial reported treatment benefits for tetanus patients. The effects of vitamin C against infections should be investigated further.
  • Hemilä, Harri (2010)
    Vitamin C and the common cold is a particularly important topic in the history of systematic reviews because three of the earliest systematic reviews examined that topic. Nevertheless, Bastian et al.'s brief mention of this issue is misleading.
  • Hemilä, Harri (2017)
    I read with great interest Dr Shader’s editorial that discussed vitamin C. I share many of his concerns about methodologic and statistical problems in the vitamin C trials. Nevertheless, some of my conclusions of the field are more positive. On the basis of the currently published findings of randomized controlled trials (RCTs), there is no justification to encourage general populations of Western countries to take vitamin C regularly to prevent colds, cancers, or cardiovascular diseases. Vitamin C, however, is a water-soluble antioxidant, and it is possible that its administration may have effects on people who have elevated levels of oxidative stress in their body. Oxidative stress is increased, for example, by heavy exertion, infections, and cardiac operations. Furthermore, the level of vitamin C synthesis is increased by various forms of stress in those animals that synthesize their own vitamin C. By analogy, larger vitamin C intakes might be beneficial for humans when they are under some forms of stress because humans are unable to synthesize their own vitamin C.