Relationship between breastfeeding and incidence rates of insulin-dependent diabetes mellitus

The incidence of breastfeeding in Scandinavian countries was high in the late 1940's, decreased gradually until a nadir in 1970 and increased again thereafter. The incidence of insulin-dependent diabetes (IDDM) in children was low in 1940, increased gradually to a peak in the late 1970s and after that has been decreasing again. The time lag (approximately 9 years) between the nadir of the breast-feeding curve and the incidence peak of IDDM is very close to the average age of the onset of disease in this population (9.3 years).