We read with great interest the article by Park et al. (1) in Diabetes Care. The results they report in middle-aged Korean men are very similar to ours published in 2007 in Diabetes Care for both sexes from the DESIR (Data from an Epidemiological Study on the Insulin Resistance Syndrome) prospective study in a Caucasian population (2). In our article, we showed that high baseline ferritin levels (above the higher tertile) were associated with a higher risk of incident International Diabetes Federation–defined metabolic syndrome in men and in menopausal women over a 6-year follow-up. Moreover, we found that high transferrin levels were also associated with this risk, either alone or in combination with ferritin. The parameters most consistently associated with baseline ferritin and transferrin were triglyceride and insulin levels. In another article (3), we described an association of both ferritin and transferrin with an increase in glucose levels during a 3-year follow-up in DESIR.
The results of Park et al. extend our results to a larger Asian population. Nevertheless, for this reason, it is unfortunate that the authors stated in their abstract that “there was no research to examine whether serum ferritin levels have been actually associated with the prospective development of [metabolic syndrome]” and in the introduction that “no prospective research has been conducted to evaluate the longitudinal association between baseline serum ferritin levels and the development of [metabolic syndrome].”
No potential conflicts of interest relevant to this article were reported.