Bone metabolic changes in Antarctic wintering team members

Bone mass, bone metabolic markers, and calcium regulation hormones were mea sured in members of an Antarctic wintering team who stayed at the Japanese Antarctic station, Syowa (latitude: south 69 degrees 00', longitude: east 3 9 degrees 35') for 1 year. Subjects included 31 healthy Japanese males, age d 24-51 years (mean age 34.5 years) at the beginning of this study, ingesti ng 488 IU/day of vitamin D and 550.9 mg/day of calcium per person. The long -term coefficient of variation (CV) of the equipment used in the assessment s of bone mass was 0.67% in single X-ray absorptiometry (SXA), 0.17% in the speed of sound (SOS) by quantitative ultrasound method (QUS), and 0.63% in broadband ultrasound attenuation (BUA) by QUS, The seasonal changes in the calcaneal bone mineral density (BMD) by SXA were not significant, whereas the SOS measured by QUS decreased during the measurement period (0.55%,p < 0.001), and BUA increased (1.9%, p < 0.01). Bone-specific alkaline phosphat ase and osteocalcin levels increased significantly during summer (p < 0.001 ) and urinary calcium level decreased significantly during winter (p < 0.05 ). Urinary pyridinoline and deoxypyridinoline levels decreased significantl y at the end of winter (p < 0.001). Serum 1,25(OH)(2)D-3 level did not chan ge significantly, whereas serum 25(OH)D-3 level decreased significantly dur ing winter (p < 0.001). Serum parathyroid hormone (PTH) level significantly increased at the end of winter (p < 0.01), although both PTH level and 25( OH)D, level remained within the normal range. We concluded that the 25(OH)D , level in subjects who stayed in Antarctica for 1 year decreased significa ntly with the reduction in duration of sunshine, but there were no clear ch anges in bone mass. (Bone 24:145-150; 1999) (C) 1999 by Elsevier Science In c. All rights reserved.