Parental Beliefs about the Etiology of Autism In a Population-Based Study

Background:  Many health care practitioners are unaware of what parents of children with autistic spectrum disorders may believe is the etiology of autism despite the strong influence of health beliefs on health behavior. Even less is known about how causal beliefs about autism may or may not differ between ethnic groups. 

Objectives:  The two aims of this study were to: 1) explore parental beliefs about the etiology of autism among families with at least one child with an autism spectrum disorder and 2) examine the relationship between race/ethnicity and causal beliefs of autism.  

Methods:  400 families with a child 2-5 years of age with a confirmed diagnosis of autism or ASD were identified from an ongoing population-based case-control Childhood Autism Risks from Genetics and the Environment (CHARGE) study. A telephone-administered Environmental Exposure Questionnaire (EEQ) is completed with the mother or primary caregiver that includes an open-ended question, “What do you think causes autism?” Multiple causes could be given. Etiological categories were arrived at based on previous literature and themes from parent responses. Parent responses were independently coded by a pediatrician and a post-doctoral fellow. All discrepancies in coding were discussed and resolved. Associations between ethnicity and causal beliefs using Pearson's chi-square tests for association or Fisher's exact test were used to assess possible associations. The three ethnic groups with adequate sample sizes for analyses were White (W) (n=198), Hispanic (H) (n=118), and Asian (A) (n=18).

Results:  After excluding 13 subjects due to missing data or duplicate sibling answers, our analysis sample included 387 parent responses.  Ethnic comparisons were made on 334 responses after excluding multiracial individuals (n=43) and African-Americans (n=10). The two most common causes of autism cited among all parents was an environmental cause (51%) and/or a genetic cause (51%). Vaccines (22%) were the third most commonly believed etiological factor, followed by 20% of parents who did not know or have a guess as to what may cause autism. There were no ethnic differences in beliefs related to genetic (W 54%, H 39%, A 44%; p=0.15), environmental (W 50%, H 48%, A 44%; p=0.88), vaccines (W 23%, H 18%, A 17%; p=0.54), maternal and prenatal causes, (W 4.0%, H 7.6%, A 5.6%; p=0.30) or any other etiological categories. The least cited cause for autism was parenting (n=1). 

Conclusions:  In all three race/ethnic groups examined, the broad groups of 'environmental' and 'genetic' each were believed to cause autism by a slight majority of parents. Vaccines are commonly cited as a cause by parents in all ethnic groups despite a clear lack of scientific evidence demonstrating a  relationship between autism and either the measles, mumps, rubella (MMR) vaccine, or thimerosal-containing vaccines. Early theories that parenting styles were a cause were not supported by this study population. Understanding parental beliefs about autism cause has important clinical implications for providing culturally-sensitive patient-centered care through parent education and informed discussions about treatment choices that would best serve their child and family.