Moon et alArticle assess the prevalence, risk covariates, and implication of medial arterial calcification (MAC) in a controlled study of healthy subjects and patients with diabetes mellitus (DM). Medial arterial calcification of legs was approximately 4 times as prevalent in population-representative ambulatory persons with DM as in healthy subjects. Advancing age, male sex, DM, and retinopathy were the significant risk covariates for MAC of legs. Medial arterial calcification of legs, although significantly associated with distal, length-dependent sensorimotor polyneuropathy (DSPN), was not a useful surrogate marker of DSPN. Also, MAC was not shown to be a risk covariate for late worsening of DSPN, although other lines of evidence suggest that peripheral arterial disease may worsen DSPN.