Bone metabolic changes in Antarctic wintering team members.

Bone mass, bone metabolic markers, and calcium regulation hormones were measured in members of an Antarctic wintering team who stayed at the Japanese Antarctic station, Syowa (latitude: south 69 degrees 00', longitude: east 39 degrees 35') for 1 year. Subjects included 31 healthy Japanese males, aged 24-51 years (mean age 34.5 years) at the beginning of this study, ingesting 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 assessments 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 phosphatase 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 significantly at the end of winter (p < 0.001). Serum 1,25(OH)(2)D-3 level did not change significantly, whereas serum 25(OH)D-3 level decreased significantly during 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 significantly with the reduction in duration of sunshine, but there were no clear changes in bone mass. (Bone 24:145-150; 1999) (C) 1999 by Elsevier Science Inc. All rights reserved.