15 e-Letters

  • Methodological considerations of a systematic review and meta-analysis: dietary carbohydrate restriction in patients with type 2 diabetes

    Thank you to the authors for addressing a relevant and interesting area of research (Snorgaard et al., 2017).

    The review was well planned, but the methodology lacks detail that enables the reader to understand the processes involved in the completion of the meta-analysis and some study limitations were not described.

    Please could the authors clarify why the meta-analyses use both mean change from baseline and mean final value in the same meta-analysis (see Figure 2 and Figure 3 where the lower means indicate change from baseline and the higher means indicate unadjusted final values)? Also, could it be clarified why the selected arms from the three-arm trials were chosen over the arms that were omitted? Although the population, intervention and outcomes were defined in the methodology, the comparator was not.

    Furthermore, when using the mean final HbA1c value in the meta-analyses, papers such as Krebs et al. (2012) and Guldbrand et al. (2012) have higher baseline HbA1cs in the lower-carbohydrate group, which was not mentioned in the paper, nor mentioned as a limitation to the meta-analysis. Guldbrand et al. (2012) demonstrate that HbA1c remained the same at two years (the time point the authors refer to) in the lower-carbohydrate arm but increased in the comparator arm by 0.2%. Therefore the low-carbohydrate arm was the superior intervention; however, the forest plot (Figure 3) suggests that the control intervention was slightly but not significant...

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  • Re:The genes associated with a high risk of type 1 diabetes are becoming less common
    Wen-Peng You
    We thank colleagues for their critical comments that help to clarify relationships we have studied. We are not concerned with the frequency of what specific genes, high-risk or not, has increased recently. We are just making a general statement that with relaxed natural selection detrimental mutations may accumulate. The paper by Witas et al. cited by our critics uses the same rationale as we do when suggesting changes in type 1 d...
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  • The genes associated with a high risk of type 1 diabetes are becoming less common
    Sarah G Howard
    In the article, "Type 1 diabetes prevalence increasing globally and regionally: The role of natural selection and life expectancy at birth" (You and Henneberg 2016), the authors find a correlation between worldwide type 1 diabetes prevalence and both life expectancy at birth and the "Biological State Index" (Ibs), a measure of population reproductive success. Based on these findings, they argue that "the correlation of Ibs to the...
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  • Re:Nutty conclusion in walnut study
    Valentine Y. Njike

    We appreciate the attention to our manuscript[1].

    We will start by emphasizing that we cannot control what has been written in the media about this study. We will therefore limit our response to the reviewer's comments that directly pertain to our manuscript.

    The results of this study are clearly enumerated in the paper, with the supporting data shown in every instance[1]. We distinguish explicitly be...

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  • Nutty conclusion in walnut study
    Stephen L. Black

    Nutty conclusion in walnut study

    This study purports to show that eating walnuts lowers cholesterol level, a claim enthusiastically and uncritically repeated in the media (e.g."A handful of walnuts a day may help lower cholesterol:study", CTV News, November 25, 2015). Unfortunately, the claim is spurious, as the published data show no such effect.

    The study is well-controlled in including a randomized control group...

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