[Comments on the epidemiologic aspects of solitary thyroid nodules]

No major criticisms can be raised concerning the paper by Jacques Leclère and co about the Epidemiological Features of the Solitary Thyroid Nodule, but a few short comments can be made, namely, 1) that is difficult to perform any comparison when the tools used for investigations are changing, making impossible any standardization of methods for examination, 2) the need for randomization in order to obtain a representative sample from the total population, 3) that no causal relationship can be concluded from a cross-sectional epidemiological study, on an observational basis.