Too many children in Canada are still developing rickets, a disease that weakens the leg bones and stunts growth, even though it is entirely preventable with vitamin D supplementation, according to a new Canadian study.
Dr. Leanne Ward, a pediatric endocrinologist at the Children's Hospital of Eastern Ontario, surveyed 2,325 pediatricians across Canada over two years and learned of an unacceptable number of cases of rickets.
The doctors reported 104 confirmed cases during the study period -- or 2.9 cases for every 100,000 children.
Ward said her figures are only an estimate of the problem because she surveyed only pediatricians. Family physicians may treat dozens of other children with rickets, especially in rural and northern settings, where pediatricians are few and far between.
Rickets is a disease caused by a deficiency in vitamin D, which has the subject of much study of late. Rickets rates are known to be higher in northern climates, where short summers mean vitamin D deficiency is more common.
Ward found that children with darker skin and those who had been breast-fed without vitamin D supplementation were most susceptible. The incidence rates were highest among children residing in the North, but 55 per cent of the cases were identified in Ontario.
Her results are published in the online edition of the Canadian Medical Association Journal.
Too little vitamin D in the diet decreases calcium and phosphate levels in the blood. When blood levels of these elements are too low, bones become weak.
Rickets can lead a bowing of the legs due to the softening of the bones, though other symptoms are also seen. They include failure to thrive, limited mobility in affected infants and seizures caused by low calcium levels. Untreated, the condition can mean a lifetime of deformity, as well as increased risk of bone fractures.
The Canadian Paediatric Society recommends that babies who are breastfed should receive a daily supplement of vitamin D from birth until they get enough vitamin D from their diet, usually from fortified milk. The recommended dose for babies is 400 IU of vitamin D per day. Babies in northern communities (north of 55锟�) should get 800 IU per day.
Babies who are formula-fed don't need a supplement, since vitamin D is already added to infant formula.
A baby born to a mother who is vitamin D deficient is more likely to have a vitamin D deficiency, so expectant mothers should also be encouraged to take a vitamin D supplement during pregnancy.
