title: Hyponatremia and Fractures: Findings From the MrOS Study.
abstract: Hyponatremia may be a risk factor for fracture. To determine the relationship between hyponatremia and fracture we conducted cross-sectional and longitudinal analyses using data from the Osteoporotic Fractures in Men (MrOS) study. The MrOS study enrolled 5122 community dwelling men aged ≥65 years from six centers across the United States. We excluded men taking bisphosphonates, those with unknown medication history, those without serum sodium measures, or those with out of range assays for serum sodium. Serum sodium was measured at study entry. Subjects were followed for fractures (nonspine [including hip], hip, incident morphometric, and prevalent morphometric) for up to 9 years. We used Cox proportional hazards models to analyze the association between serum sodium levels (<135 mmol/L versus ≥135 mmol/L) and risk of nonspine and hip fractures, with results presented as hazard ratios (HRs) and 95% confidence intervals (CIs). We examined the association between morphometric vertebral fractures and serum sodium using logistic regression models, presented as odds ratios (ORs) and 95% CI. Hyponatremia was observed in 64 men (1.2% of the cohort). After adjusting for age, BMI, study center, and other covariates, we found that, compared to men with serum sodium ≥135 mmol/L, those with serum sodium <135 mmol/L, had an increased risk of hip fracture (HR = 3.04; 95% CI, 1.37 to 6.75), prevalent morphometric spine fracture (OR = 2.46; 95% CI, 1.22 to 4.95), and incident morphometric spine fracture (OR = 3.53; 95% CI, 1.35 to 9.19), but not nonspine fracture (OR = 1.44; 95% CI, 0.85 to 2.44). Adjusting for bone mineral density (BMD) did not change our findings. Our data show that hyponatremia is associated with up to a doubling in the risk of hip and morphometric spine fractures, independent of BMD. Further studies, to determine how hyponatremia causes fractures and if correction of hyponatremia decreases fractures, are needed.
authors.affiliation: Women's College Research Institute, University of Toronto, Toronto, ON, Canada.
authors.forename: Sophie A
authors.initials: SA
authors.lastname: Jamal
authors.affiliation: Department of Nephrology, Hypertension, and Clinical Pharmacology, University Hospital Bern (Inselspital), University of Bern, Bern, Switzerland.
authors.forename: Spyridon
authors.initials: S
authors.lastname: Arampatzis
authors.affiliation: Research Institute, California Pacific Medical Center, San Francisco, CA, USA.
authors.forename: Stephanie Litwack
authors.initials: SL
authors.lastname: Harrison
authors.affiliation: Women's College Research Institute, University of Toronto, Toronto, ON, Canada.
authors.forename: Roxana C
authors.initials: RC
authors.lastname: Bucur
authors.affiliation: Department of Medicine, University of Minnesota, Minneapolis, MN, USA.|Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, MN, USA.|Center for Chronic Disease Outcomes Research VA Health Care System, Minneapolis, MN, USA.
authors.forename: Kristine
authors.initials: K
authors.lastname: Ensrud
authors.affiliation: Bone and Mineral Section, Division of Endocrinology, Diabetes, and Clinical Nutrition, Oregon Health and Science University, Portland, OR, USA.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Orwoll
authors.affiliation: Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.|Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Bauer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000150:complications / Q000453:epidemiology; D008297:Male; D012307:Risk Factors; D012964:Sodium / Q000097:blood; D016103:Spinal Fractures / Q000097:blood / Q000453:epidemiology / Q000209:etiology; D014481:United States
chemical_list: D012964:Sodium
keywords: DXA; FRACTURE RISK ASSESSMENT; GENERAL POPULATION STUDIES; OSTEOPOROSIS; SYSTEMS BIOLOGY-BONE INTERACTIONS