Vitamin D deficiency experienced in Antarctica
Photo: Frederique Olivier
The research follows a pilot study reported in Australian Antarctic Magazine 8: 29 (2005), and was conducted by Dr Sandra Iuliano-Burns and colleagues from the University of Melbourne, Dr Jeff Ayton of the Australian Antarctic Division, and Professor Graeme Jones of the Menzies Institute.
Vitamin D deficiency is common during winter in many countries, due to a lack of sun exposure. Without vitamin D the body cannot absorb as much calcium, so it turns to the supplies of calcium in the bone, resulting in bone loss. One of the key questions the study hoped to answer was whether this bone loss was transient or irreversible.
The study found an increase in bone turnover (the extraction and replacement of calcium in the bone, by the body) about six months after vitamin D deficiency was observed. Bone mass density was found to be reduced in the 'proximal femur' (thigh bone, near the hip), but not in the lumbar spine (lower back). Individuals with bone loss, however, had lower dietary calcium intakes, suggesting that supplementation of these individuals may be beneficial in suppressing bone turnover.
As the bone loss experienced in the study group was small (1 ± 2 %) and of uncertain biological significance, and follow-up bone density data was unavailable, the permanency of bone loss could not be confirmed by the study. However, continued research during future Antarctic expeditions may resolve this. The study concluded that baseline vitamin D levels in expeditioners should be assessed prior to prolonged sunlight deprivation, and supplementation may be necessary for those with reduced levels.
More information: Iuliano-Burns S, Wang X. F, Ayton J, Jones G and Seeman E. Skeletal and hormonal responses to sunlight deprivation in Antarctic expeditioners. Osteoporosis International Published online: 17 January 2009.
Expedition and Wilderness Medicine
Photo: Paul Peterson
Drs Ayton and Lugg point out that many people travelling on polar expeditions are more likely to develop signs and symptoms of diseases contracted in temperate or tropical climates before the journey. There are, however, a range of polar medical problems, including dehydration, cold injury – such as frostbite and polar hands – sunburn, and snow blindness caused by UV burns to the eyes.
The chapter includes a review of illnesses, injuries and medical procedures over 17 years of the Australian Antarctic program (1989-2005) and the factors to consider when planning expedition health care. These include field activities and medevac capabilities; facilities, equipment and supplies required; selection and training of medical staff; telemedicine; and medical research.
Expedition and Wilderness Medicine is available from Cambridge University Press
Corporate Communications, AAD
Next article: In Brief