The scientific aims of the project have been changed since the grant was awarded. The aims are now to study how children?s risk of autism spectrum disorder (ASD) is affected by the following exposures:
(1) Maternal iodine status in pregnancy.
Idoine is crucial for brain development, particularly during fetal life. During the first half of pregnancy, the embryo/fetus is dependent on the supply of thyroid hormones from the mother, while in the second half of pregnancy it can produce its own thyroxin as long as the supply of iodine is sufficient. Adequate levels of iodine in the mother can only be maintained through dietary intake, and good sources of iodine are dairy products and seafood. Severe iodine deficiency during pregnancy leads to severe developmental disturbances in the child, such as cretinism and intellectual disability. Mild to moderate iodine deficiency during pregnancy is associated with lower verbal IQ scores, reduced reading comprehension and reading precision, behavioral problems and reduced fine motor skills at three years of age, and with a higher ADHD symptom load at eight years of age. These characteristics are also typical of children with ASD. In the last five years, studies have shown that the prevalence of mild to moderate iodine deficiency is high among pregnant women in Norway: between 40% and 80% have a iodine intake below the recommended daily intake. Iodine deficiency increases the risk of thyroxin deficiency, while thyroxin deficiency in the first half of pregnancy is associated with an increased risk of ASD. The association between maternal iodine intake in early pregnancy and children?s risk of ASD has never been studied.
(2) Maternal vitamin D status during pregnancy.
The hypothesis of an association between vitamin D and ASD originates from 2008, when a report from Stockhold described a high prevalence of ASD among children of Somali immigrants. Around the same time, a similar hypothesis was generated on the basis of animal studies and an increase in vitamin D deficiency in the general population. The increase in vitamin D deficiency is caused by increased awareness of the dangers of sun exposure and the risk of malignant melanoma. Since then, several scientific papers have provided findings that indicate associations between low levels of vitamin D during pregnancy and subsequent risk of developmental disorders such as ASD and schizophrenia in the children. A number of papers have also shown that children with ASD have lower levels of vitamin D than children with normal development, and children with ASD have lower vitamin D levels at birth compared with normally developed siblings. One study has shown that low levels of vitamin D in mid-pregnancy is associated with increased risk of ASD in the child. This study was small (68 ASD cases), but had the advantage of utilizing measured levels of vitamin D in blood samples obtained from the mother during pregnancy. In the Norwegian Mother and Child Cohort Study, vitamin D levels have been measured in a subset of the mothers who participate. These results can be used to predict levels of vitamin D in the other mothers. With more than 800 identified ASD cases, MoBa may provide important contributions to study the association between vitamin D status during pregnancy and risk of ASD in the children.
Prosjektet avsluttes uten at de vitenskapelige målene er nådd. Opprinnelig skulle prosjektet vært basert på laboratorieanalyser utført ved Columbia University. Laboratorieanalysene ble forsinket, og data ble ikke gjort tilgjengelige for oss. Vi laget deretter en ny prosjektbeskrivelse med nye vitenskapelige mål. Vi mente forutsetningene var til stede for å gjennomføre prosjektet, og satte i verk tiltak fra avdelingens side for å hjelpe til. Prosjektperioden ble utvidet fordi stipendiaten hadde en svangerskapspermisjon og noen lengre sykmeldingsperioder. Vinteren 2021 valgte hun å si opp stillingen før stipendiatperioden var ute. Det hadde da ikke kommet noen publikasjoner fra prosjektet. Vi har ikke klart å mobilisere andre folk internt til å fullføre. Se forøvrig rapport lastet opp under "Resultatrapport".
The project will utilize data from the Norwegian Mother and Child Cohort Study and the Autism Birth Cohort study to investigate the associations between (1) maternal iodine status during pregnancy and children's risk of autism spectrum disorder and (2) maternal vitamin D status during pregnancy and children's risk of autism spectrum disorder.