SAT-LB093 Salty Relationships with Bone: Not Calcium nor Vitamin D

Previous studies demonstrated a positive relationship between blood sodium concentration and bone mineral density (BMD) in ultramarathon runners following a 100-mile race (1) and a negative relationship in walkers (treadmill walking for 45-minutes) following an oral sodium load (2). However, accurate assessment of sweat sodium concentration ([Na + ]) was absent in those exercise studies. Therefore, the primary aim of these pilot data were to assess potential relationships between sweat [Na + ] versus bone mineral content (BMC) at rest. We hypothesized that higher sweat [Na + ] would be associated with lower BMC in athletes participating in a larger vitamin D supplementation trial. The current data represent a cross-sectional baseline assessment whereas: sweat [Na + ] was obtained via pilocarpine iontophoresis (Wescor), total body BMC, fat and lean mass obtained via dual energy x-ray absorptiometry scan (Hologic), serum 25-OH vitamin D (25-OH-D) obtained via venipuncture (Cobas E Immunoassay), and dietary intake assessed via 3-month Food Frequency questionnaire (NutritionQuest). Twenty-two male (n=13) and female (n=9) collegiate basketball players completed baseline testing (20±2years). Significant relationships between total body BMC vs. sweat [Na + ] (r=0.54;p=0.01) and total lean mass (r=0.93;p