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Text sizeLondon, UK A new report suggests children who received vitamin D supplementation as infants were less likely to develop type 1 diabetes later in life - a reduced risk on the order of 80%. Assuring children have enough of the "sunshine" vitamin may help reverse the growing trend in the incidence of type 1 disease, the researchers suggest. The report appears in the November 3, 2001 issue of the Lancet.1
Type 1 diabetes is thought to be an autoimmune disorder, and vitamin D acts as an immunosuppressant, "so these findings are not surprising," Dr Elina Hyppönen (Institute of Child Health, London) and colleagues write. "Impairment of immune system functioning by a suboptimum vitamin D status in infancy could have long-term effects on immune responses later in life."
Finnish cohort
Their birth-cohort study included 12058 live births of women living in Oulu and Lapland in northern Finland in 1966. Data were collected on vitamin D supplementation and the presence of suspected rickets (a metabolic bone disease prevented by vitamin D) in 10366 of the children at a follow-up visit during their first year of life. They were then followed for the incidence of type 1 diabetes until 1997.
Vitamin D supplementation was associated with a much-reduced risk of developing the disease: subjects who regularly took the recommended daily dose of 2000 IU of vitamin D had a rate ratio of 0.22 (95% CI 0.05-0.89) compared with those who regularly received less than the recommended amount. Children suspected of having rickets during that first year of life had a RR of 3.0 (1.0-9.0) compared with those for whom there was no such concern.
Trends conspiring to reduce Vitamin D?
In an editorial accompanying the publication, Dr Jill M Norris (University of Colorado Health Sciences Center) calls the possibility that vitamin D might have a role in the pathogenesis of type 1 diabetes "intriguing."2
She points out that further study is required to examine doses, timing, and potential toxicity of supplementation before interventional trials are undertaken.
Norris also speculates that three current public health initiatives may be coming together to reduce vitamin D exposure in children.
"The emphasis on breast-feeding (breast milk does not contain sufficient vitamin D for infant needs), the advice to keep babies out of the sun, and the increase in the use of sunscreen when infants and toddlers are in the sun may act together to decrease the intake and synthesis of the sunshine vitamin," she concludes.
