Very sick children are often vitamin D deficient, a study published this week in Pediatrics reports. The results, from a large study in Canada, represent the first search for a link between vitamin D levels and critical illness in children, though smaller studies have already found the same relationship in sick adults.
The study evaluated blood levels of the vitamin in 326 children hospitalized in Canadian pediatric intensive care units. Nearly 70 percent of these kids had deficient vitamin D levels. The lowest levels of vitamin D were associated with more-severe illness at the time of hospital admission and also with longer stays in the pediatric intensive care unit.
Kids who were deficient in vitamin D also had lower calcium levels, an unsurprising finding given that vitamin D regulates calcium metabolism. The scientists suggest that in some cases, low vitamin D may actually be caused by the treatments kids get in the hospital -- for instance, giving large quantities of fluid can dilute a child's blood and cause vitamin D concentrations to drop. Low vitamin D could worsen illness via several mechanisms, the researchers add, pointing to earlier studies that implicate low vitamin D levels in (among other things) heart failure, poor immune function, sepsis, asthma, nerve dysfunction and muscle weakness.
The next step in the research is to test whether giving sick children vitamin D helps them recover more quickly, the scientists concluded.