Univariate regression analysis showed that sex (r = 0.177, p = .002), HbA1c levels (r = 0.040, p < .001), serum phosphate (r = 0.236, p < .001), calcium (r = 0.125, p = .030), CPP (r = 0.236, p < .001), alkaline phosphatase (r = 0.201, p < .001), and PTH (r = 0.122, p = .035) were significantly associated with logFGF23 levels in the T1D group. Here, PTH is linked to type 1 diabetes mellitus.