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Bone and Mineral Metabolism

MON-803 - Higher PTH level is associated with lower bone mass, microstructure, and strength in adults with type 1 diabetes and mild to moderate diabetic kidney disease

Monday, June 15, 2026
9:00 AM - 2:00 PM CT


Background: Renal dysfunction is associated with worse skeletal outcomes in individuals with type 1 diabetes (T1D). Mechanistically, less is known about the impact of parathyroid hormone (PTH) on skeletal health in T1D, particularly in those with mild to moderate diabetic kidney disease (DKD). The extent to which PTH mediates the association between renal dysfunction and bone is not well understood. We characterized the relationships between PTH and bone mass, microstructure, and estimated strength among adults with mild to moderate DKD.

Methods: We performed an ancillary study to the Preventing Early Renal Loss in Diabetes (PERL) trial, a completed multi-center randomized controlled trial of allopurinol to slow decline in glomerular filtration rate (GFR) in adults with T1D and mild to moderate DKD. PTH was measured at 3 time points during and post-trial, and dual-energy X-ray absorptiometry and high-resolution peripheral quantitative computed tomography were performed post-trial. We calculated time-weighted averages of PTH and gold-standard iohexol-GFR (iGFR) as best linear unbiased predictions using generalized linear mixed models. Associations between PTH and bone outcomes were analyzed via linear regression, adjusted for covariates, then PTH was evaluated as a potential mediator of the associations between iGFR and bone.

Results: Our cohort’s 97 adults (aged 60±10y, 65% male, 86% white, A1c 7.4±1.1%) represented the following KDIGO distribution: G2 33, G3a 24, G3b 25, and G4 15. Most PTH values were within normal range; mean was 50.5 ±22.7 pg/mL. Higher PTH concentration was associated with lower bone mineral density (BMD) at the spine and radius and lower trabecular bone score (TBS) (mean difference total spine BMD -0.042 g/cm2 [95% CI -0.083, -0.001] per 1 SD higher PTH; 1/3 radius -0.026 [-0.046, -0.005]; TBS -0.042 [-0.067, -0.016]). Microarchitecture was worse at higher PTH levels, with lower trabecular thickness (radius: -0.002 mm [-0.004, -0.0003] per 1 SD higher PTH) and higher cortical porosity (tibia: 0.6% [0.1, 1.1]). By finite element analysis, higher PTH was associated with lower bone strength, with more prominent effects at the tibia (stiffness at the radius: -5117 N/mm [-8959, -1275] per 1 SD higher PTH; tibia: -11291 [-19652, -2930]). As previously reported, lower iGFR was associated with lower BMD and bone strength; adjustment for PTH substantially attenuated these associations (e.g., mean difference in stiffness at the tibia attenuated -19,972 N/mm to -8,943 N/mm, per 30-ml/min/1.73 m2 lower iGFR).

Conclusions: In adults with T1D and mild to moderate DKD, higher PTH concentration is associated with worse skeletal health. Higher cortical porosity and lower trabecular thickness offer explanations for skeletal fragility. PTH level explains a substantial proportion of the negative impact of DKD on bone outcomes.

*Unless otherwise noted, all abstracts presented at ENDO must not be released to the press or the public until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.*