The pre-diabetic autoimmune process leading to clinical type 1 diabetes may start already during early infancy. As the incidence of type 1 diabetes is increasing most rapidly among children younger than 5 years in many high and middle income countries (Patterson et al. 2009), there is increasing interest in the impact of early exposures such as diet even before birth.
Vitamin D has several effects on the immune system, which could be of potential relevance in the pathogenesis of type 1 diabetes. Maternal vitamin D intake and status during pregnancy affects the vitamin D status of the fetus and the newborn baby. Vitamin D supplementation during infancy may protect from type 1 diabetes as suggested by case-control findings from an European wide study (The EURODIAB Substudy 2 Study Group 1999) as well as by cohort findings from Finland (Hyppönen et al. 2001). In a Norwegian case-control study, the use of cod liver oil (rich in vitamin D) but not vitamin D supplementation as such during the first year of life was associated with lower risk of type 1 diabetes (Stene et al. 2003).
Findings whether maternal vitamin D intake protects the child from pre-clinical type 1 diabetes are discordant. In an US cohort, maternal intake of vitamin D from food, but not from supplements during pregnancy was associated with a decreased risk of early islet autoimmunity appearance in the offspring (Fronczak et al. 2003). In a Swedish cohort study a weak inverse association was observed between maternal vitamin D supplementation and appearance of diabetes-associated autoantibodies at the age of 1 year but not at 2.5 years (Brekke & Ludvigsson 2007). In a Finnish cohort study in which a more advanced pre-type 1 diabetes endpoint was used and where the number of endpoints outnumbered the previous studies, no association was shown between maternal intake of vitamin D either from food or supplements (Marjamäki et al. 2010). Neither was vitamin D intake related to the development of clinical type 1 diabetes in that study.
30 Apr - 04 May 2011
European Society of Endocrinology