It has been suggested by some that increased consumption of vitamin D by infants and toddlers may decrease the risk of developing autism. To examine this hypothesis a model was constructed to estimate how much vitamin D was consumed on average by infants and toddlers in the United States at five year intervals between 1980 and 2010. In addition estimates of autism prevalence among children entering school in the United States from 1985 to 2012 were made using data from the California Department of Developmental Services and United States Department of Education. The model shows that oral vitamin D consumption among this population has increased by 94% between 1980 and 2005 and by about 112% between 1980 and 2010. Autism prevalence among the young also increased by approximately 2300% from 1985 to 2010. Thus vitamin D consumption increased significantly and autism prevalence increased even more over these time periods. Further analysis shows that the natural log of the autism prevalence is proportional to the average level of vitamin D consumption five years previously. In other words, the data suggest that the hypothesis is false.
Keywords: Epidemiology, supplementation, fortification, vitamins