Ingesta de vitamina C y susceptibilidad al resfrío común.

CRD COMMENTARY:

The author has relied on previous reviews as the basis for the literature search, which were then supplemented by searches of two databases. It is unclear whether additional relevant studies may have been missed, since there is no mention of unpublished data, abstracts and non-English language studies in the searches. [A:Additional information received from the author shows that the search strategies were very extensive.]
The selection methods for the studies, and the validity and quality assessment measures of the included studies, were not included. In addition, the methods used to extract the data were not reported.
The author summarised the data in tabular format, and pooled the results from the individual studies using rate ratios and relative risk statistics. Heterogeneity between the studies was neither tested nor evaluated.
The author's conclusions should be viewed with caution because the quality of the included studies was not assessed, differences between the studies were not evaluated, and the only statistical significance was found in a very specific subset of the study populations and these results may be attributable to other causes.