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Abstract: TH-PO157

Dietary Vitamin K Is Inversely Associated with Parathyroid Hormone (PTH) in People with CKD: The PROGREDIR Cohort Study

Session Information

Category: Bone and Mineral Metabolism

  • 502 Bone and Mineral Metabolism: Clinical

Authors

  • Machado, Alisson Diego, Universidade de Sao Paulo Faculdade de Saude Publica, Sao Paulo, São Paulo, Brazil
  • Marchioni, Dirce, Universidade de Sao Paulo Faculdade de Saude Publica, Sao Paulo, São Paulo, Brazil
  • Bensenor, Isabela M., Universidade de Sao Paulo Faculdade de Medicina, Sao Paulo, São Paulo, Brazil
  • Lotufo, Paulo, Universidade de Sao Paulo Faculdade de Medicina, Sao Paulo, São Paulo, Brazil
  • Moyses, Rosa M.A., Universidade de Sao Paulo Faculdade de Medicina, Sao Paulo, São Paulo, Brazil
  • Titan, Silvia, Mayo Clinic Minnesota, Rochester, Minnesota, United States
Background

Dietary intake has a relevant role in mineral and bone disorder in chronic kidney disease (CKD-MBD), being an important part of the treatment of this condition. However, most studies have focused on intake of phosphorus and calcium, and there is limited literature on possible nutritional determinants of parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23). In this study, we evaluated the association of macro and micronutrients from dietary intake with intact PTH (iPTH), 1-84 PTH, and FGF23 in a cohort of people with CKD.

Methods

We included 441 participants from the Progredir Study, a cohort of people with CKD based in São Paulo, Brazil. Food and nutrient intakes were estimated by a food frequency questionnaire. We evaluated the association of these variables with iPTH, 1-84 PTH, and FGF23 by linear regression using SPSS software (version 21).

Results

The median age and 2021 CKD-EPI eGFR were 68 years old and 40 mL/min/1.73 m2, respectively. The median iPTH was 92 pg/mL (IQR 63, 140), 1-84 PTH was 36 pg/mL (IQR 28, 51), and FGF23 was 93 pg/mL (IQR 69, 128). In the univariate linear regression, vitamin K was associated with log iPTH and 1-84 PTH. No associations were observed for FGF-23 and macro or micronutrients. After adjusting for age, sex, eGFR, skin color, diabetes, nutritional status, energy intake, serum calcium, calcium carbonate use, and warfarin use, vitamin K intake remained associated with iPTH (β = -0.13, 95% CI -0.21, -0.04, p = 0.003). Similar result was seen for 1-84 PTH (β = -0.08, 95% CI -0.14, -0.02, p = 0.02).

Conclusion

In these analyses, dietary vitamin K intake was inversely associated with iPTH and 1-84 PTH, even after adjustments for possible confouding variables. To our best knowledge, this is the first study to show this association. Future studies are needed to replicate this finding, investigate mechanisms underlying this association, as well as determine whether interventions in vitamin K lead to changes in PTH levels.

Funding

  • Government Support – Non-U.S.