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Bone metabolism and renal stone risk during bed rest for men and women (257.8)
Author(s) -
Morgan Jennifer,
Heer Martina,
Hargens Allen,
Macias Brandon,
Hudson Edgar,
Shackelford Linda,
Zwart Sara,
Smith Scott
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.257.8
Subject(s) - bed rest , rest (music) , bone remodeling , renal stone , medicine , osteoporosis , bone resorption , population , spaceflight , endocrinology , incidence (geometry) , urine , bone mineral , resorption , physiology , urinary system , physics , environmental health , optics , engineering , aerospace engineering
Bed rest is a model to simulate and study the human physiological adaptations to spaceflight, for example changes in bone metabolism and renal stone formation. On Earth, the incidence of osteoporosis in women is about double that of men while the incidence of stone formation is more likely in men. These sex specific differences lead to logical questions about the existence of sex‐specific effects during spaceflight that can be tested in the bed rest model. In this study, we combined data from five bed rest studies (n=50 men, 24 women) ranging in duration from 14 ‐ 90 days to assess sex differences in bone loss, bone biochemistry, and renal stone biochemistry. Prior to bed rest, men had higher bone mineral density and content (P < 0.001), and excreted 30 % more biomarkers of bone resorption (i.e., collagen crosslinks) and 20 % more calcium per day than did females (P <0.05). These offsets remained throughout the duration of the bed rest periods. Urine renal stone biochemistry was significantly altered for both men and women during bed rest, resulting in men having an increased renal stone risk compared to the general population. Actual renal stone risks in these studies were reduced by maintaining a high amount of fluid intake (>2.5 L/d). These results indicate that overall both men and women are equally affected by the skeletal unloading of bed rest.