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Autism Birth Cohort Study (ABC Study) - project description


The purpose of the Autism Birth Cohort Study is to describe the development path and risk factors for autism spectrum disorders.



The ABC Study is a large research project conducted by the Norwegian Institute of Public Health (NIPH) in collaboration with Columbia University in New York (USA) and the Nic Waals Institute at Lovisenberg Hospital in Oslo.

It is nested within the Norwegian Mother and Child Cohort Study (MoBa) and will study risk factors, clinical traits and disease trajectories among children with autism spectrum disorders.

The most important symptoms of autism are reduced social functional level, language difficulties and restricted and repetitive behaviour patterns. Social function difficulties are often displayed as a lack of interest in other children and parents may have difficulty connecting with the child. Language development is often delayed or impaired but many also have normal speech.

There are many different types of autism, including childhood autism and Asperger syndrome, so the term autism spectrum disorders (ASD) is commonly used.

The scope of the ABC Study is to identify all children with ASD among MoBa participants and to collect clinical information for use in research, either through clinical assessment or from patient records. By combining these clinical data with the available MoBa data, the risk factors for ASD development and the potential causes will be investigated. We will also identify early signs of ASD, describe clinical symptoms and study how the children develop as they grow.

The overarching goal of the ABC Study is to find possible causes of ASD by studying the role of genetic and environmental factors, either in combination or independently. By learning more about the causes we hope to contribute to more accurate diagnosis, quicker interventions, and future knowledge about how to prevent development of autism in children.

Scientific aims

The scientific aims of the study are as follows:

  1. Identify all suspected ASD cases in MoBa and clinically assess the children, together with a random sample of children with typical development.
  2. Study environmental factors that can affect the risk of developing ASD among children. 
  3. Describe disease trajectories and additional problems among children with ASD.

Material and methods

The ABC Study is based on MoBa. Between 1999 and 2009, MoBa recruited over 112,000 pregnant women and their partners during the first hospital ultrasound examination, usually at week 18 of pregnancy. MoBa now has 114,500 children, plus their parents, as participants. The parents have completed questionnaires about health, lifestyle, diet, housing, social and financial conditions.

Blood and urine samples were collected from the mother at the ultrasound examination together with a blood sample from the father. At birth, blood samples were collected from the umbilical cord of the infant along with a second sample from the mother.

Since birth, MoBa participants are followed up with questionnaires at defined intervals. The goal is to follow all participants until adulthood in order to identify risk factors and causes of disease, and hopefully contribute to prevention of disease in children and their parents.

The ABC Study used questionnaire data from MoBa and information from the Norwegian Patient Registry to identify children with a suspected ASD. From 2005 to 2012, children with a suspected ASD were invited for clinical assessment at the study clinic operated in collaboration with the Nic Waals Institute, together with a random group of children with apparent typical development. Relevant information from patient records was collected for participants who were unable to attend the clinical assessments. The information extracted from the patient records is equivalent to that collected in the clinical assessment in the study clinic.

The information from the clinical assessments and MoBa is the foundation for research in the ABC Study.

Data handling

Data collected in the ABC study is used exclusively for research purposes. In order to protect the personal data of our participants, all person identifiable information such as names and national identity numbers are removed before researchers are allowed to access the data.

Researchers at the NIPH will analyse the data in collaboration with researchers at our partner institutions.


The ABC Study is approved by the Regional Committee for Medical and Health Research Ethics with the case number S-03228. The study has a licence from the Norwegian Data Protection Authority, reference 04/00406.

Participants in the ABC Study are MoBa participants. Through their participation in MoBa they have consented to research being carried out in projects such as the ABC Study. Data collection from health registries, including patient records, are covered by this consent.

Specific consent was obtained from participants for the clinical assessments.


The National Institute of Neurological Disorders and Stroke (NINDS) in USA has funded the ABC Study since 2003. Funds have also been provided by the Research Council of Norway and Norwegian Institute of Public Health. 

About the project

Responsible FHI

Therese Wardenær Bakke