Pediatrics professor Dr Gordon Klein from the University of Texas and his colleagues discovered that children with burns over more than 40 per cent of their bodies do not make enough vitamin D on their own to produce strong bones.
Vitamin D, known as the 'sunshine vitamin', is made by the skin through exposure to sunlight. But in burned children, even skin that is not burned cannot make enough vitamin D, the researchers report in tomorrow's issue of The Lancet (volume 363, no 9405).
"This phenomenon becomes worse with time, rather than better," Klein said.
Burn patients are known to suffer from a high incidence of bone fractures later in life. This research may explain why.
Vitamin D, which helps bones absorb calcium, is crucial to the development of strong bones. Vitamin D deficiency can lead to osteomalacia (soft bones) or, in extreme cases, rickets, a disease of the young characterised by soft and deformed bones. Recently doctors have noticed a resurgence of this disease, largely wiped out several decades ago.
Children lose bone mass after being burned. Though their bone mass regenerates with time, new bone tissue in burned children is not as dense as the bone tissue of children who have not suffered burns.
The researchers studied skin biopsies of 12 children treated at Galveston's Shriners Burns Hospital, which treats children from across the world free of charge. Researchers tracked the patients' vitamin D levels for seven years. They found that burned children's skin becomes so inefficient at producing vitamin D that exposure to sunlight alone would not produce enough vitamin D.
Vitamin D supplements should become part of burned children's therapy during their treatment and after they are discharged from the hospital, Klein said.
While the team did not analyse vitamin D levels in adult burn patients, Klein said there was no reason to think the situation would be different for adults. More research is however required to assess whether burned adults' bodies experience similar inabilities to properly synthesise vitamin D from sunlight.