Studies without control group or with control group exluded from meta-analysis.

1data were included only when it was clearly reported if given time was the time since diagnosis or since estimated onset of the disease;2at the time of diagnosis;3estimated time of duration of the disease;4Palpable nodules only.511 patients examined only by palpation were excluded; descriptive statistics refer to the whole group;Abbreviations: SD – standard deviation; SIR – standarized incidence ratio; TC – thyroid cancer; TND – thyroid nodular disease.