Biomarkers of Mineral and Bone Metabolism and 20-Year Risk of Hospitalization With Infection: The Atherosclerosis Risk in Communities Study.

Context: Mineral and bone disorders (MBDs) might be relevant in the etiology of infection. Objective: To determine whether MBD biomarkers were associated with the incidence of hospitalization with infection. We also assessed the cross-sectional association between MBD biomarker levels and kidney function. Design, Setting, Participants: Community-based cohort study of 11,218 participants with an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73m2 in the Atherosclerosis Risk in Communities study. We assessed the cross-sectional associations of five MBD markers-fibroblast growth factor 23 (FGF23), 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), calcium corrected for hypoalbuminemia, and phosphorus-with eGFR from 1990 to 1992 and their longitudinal associations with incident hospitalization with infection in 1990 to 2013. Main Outcome: Incident hospitalization with infection. Results: In age-, sex-, and race-adjusted models, lower eGFRs were significantly associated with greater levels of FGF23, PTH, and corrected calcium but not 25(OH)D or phosphorus. During follow-up, 5078 hospitalizations with infection occurred. In fully adjusted Cox models, with the second quartile as the reference, the hazard ratio (HR) was significantly greater in the highest quartile of FGF23 [HR, 1.12; 95% confidence interval (CI), 1.03 to 1.21], PTH (HR, 1.09; 95% CI, 1.01 to 1.18), and corrected calcium (HR, 1.11; 95% CI, 1.03 to 1.20), and lowest quartile for 25(OH)D (HR, 1.11; 95% CI, 1.03 to 1.21). The association with phosphorus was significant only when the outcome was restricted to primary diagnosis of infection. These findings were consistent across subgroups of age, sex, race, and eGFR (<60 vs ≥60 mL/min/1.73 m2). Conclusions: MBD biomarkers were associated with eGFR and the subsequent risk of infection, supporting MBD involvement in the etiology of infection.