Does prolonged sun deprivation in Antarctic conditions cause irreversible bone loss?

Vitamin D deficiency is detrimental to the skeleton resulting in accelerated bone loss, and reductions in bone mineral density (BMD). The main source of vitamin D in healthy people is that which they produce in the skin when it is exposed to ultraviolet (UV) radiation eg. sunlight. During winter when there is less sunlight, less vitamin D is produced and bone loss increases. This seasonal change to bone is reversed once the skin is exposed to sunlight again. The longer a person is not exposed to sunlight, the greater the detrimental effect on bones. It is not known if prolonged periods of sun deprivation will permanently effect bone. Studying healthy adults during their time in Antarctica, when UV exposure is negligible provides valuable information about the effect of prolonged sun deprivation on bone. Following the expeditioners up on their return to a temperate climate will reveal if the detriment to bone is transient or permanent. Findings from this study may have applications beyond expeditioners to include elderly in aged care and space travel.Baseline blood samples (as at 2004-06-30):LocationNumberMacquarie Island14Casey14Davis20Mawson163 month blood samples:Mawson156 month blood samples and diet records:Mawson17