Интересный коммент:
Цитата:Peter Garvin ORCiD commented on 05 May, 2020
With all respect, this study can't be used neither to support nor reject the hypothesis. If this would have been a wriiten exam in epidemiology, I would have failed the students for the following reasons:
1) Data clearly suggests that is not appropriate to use t-test. As you all know, incidence rates are seldomly normally distributed. Having a STDEV that exceeds the mean is not a good sign, it indicates that the entire analysis is idependent on one or a few outliers.
2) Number of tested persons with positive result is not a good proxy for number of cases in the population. It has been clear from the start the different countries has applied different approaches regarding number of tests as well as which groups should be tested. (Not to mention the specificity and sensitivity issues).
3) Since the mortality rates vary highly with age, analyses should have been age standardized in some way. It is almost sad to see that the authors claim to minimize confounding without taking demographics into account. This could have been easily done, stratifying the material based on age groups and standardize for age specific vitamin D reference interval (or at least estimations of age specific intervals).
4) The correlation in Figure 2 on mortality implies that, given that the correlation is true, you could have a negative mortality rate. Clearly, linear fitting is not always ideal, and this could, I am afraid, be used as a school book example to illustrate that. Apart from the note on philosophy of science that a correlation cannot be "very significant" as stated, the coefficient seems to be highly depending on one single outlier. (Further, it seems that the different countries are not weighted in relation to population size, which supersizes the impact of small countries).
I could go on, but I think my message is clear. I have no wish neither to support or reject the hypothesis on vitamin D. There is a need for carefully considered and planned analyses to increase our understanding. This paper does simply not meet the scientific standard needed to conclude that vitamin D supplementation should be used to protect against COVID–19 infection. It is not the design per se that limits the value (which by the way is ecolological rather than cross-sectional as stated), it is the amount of methodological flaws in the analyses.
И обратите внимание на дату!!!
И да, еще раз для понимания.
Я не против того, что нужно пить витамин Д против коронавируса. Пейте сколько разрешено, хуже Вам точно не будет.
Я против того, чтобы люди кидались в аптеки, выгребали витамин Д, запихивались им под завязку, а потом, нахлдясь по эффектом фальшивой эйфории и безопасности, пренебрегали элементарными нормами карантина и масочного режима.
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