Prosnitz AR, Leonard MB, Shults J, et al. - Researchers studied relationships between 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D], and parathyroid hormone (PTH) levels in incident pediatric CD, compared with controls, and following diagnosis. Serum vitamin D and PTH have been measured at diagnosis (n = 78), 6, 12, and a median of 43 months (n = 52) later in CD participants, and once in 221 controls. Data reported that 42% of CD candidates were 25(OH)D-deficient (< 20 ng/mL) at diagnosis. According to results, TNF-α was associated with lower 1,25(OH)₂D and there was no positive association in controls between PTH and 1,25(OH)₂D in CD. Findings suggested an association of incident CD with 25(OH)D and 1,25(OH)₂D deficiency and a relative hypoparathyroidism that resolved following diagnosis. Such changes may be caused by inflammatory cytokine suppression of PTH and renal 1-α-hyroxylase.