Our study includes the following limitations: (1) the cross-sectional design precludes us from knowing the predictive value of serum NFL; (2) the inclusion of individuals with well-controlled diabetes for whom the extent of nerve damage is lower than individuals with less-controlled diabetes; (3) the predominance of subclinical DSPN prevents us from assessing the associations between serum NFL and DSPN stages; and (4) the lack of statistical power to stratify the analyses by diabetes type. Here, NEFL is linked to diabetes mellitus.