AAAP Today

GENETICS By Far the Biggest Risk Factor in Autism

by Lirio S. Covey, Ph.D.

A massive, rigorous study using multi-generational population data from five countries concluded that inherited genes account for about 80% of the risk for autism. Environmental factors accounted for 20% of the risk.

The entire sample included more than two million (2,001,631) individuals, of whom 22,156 were diagnosed with autism spectrum disorder (ASD).

The data were collected from 5 countries – Denmark, Finland, Sweden, Israel, and Western Australia between January 1998 and December 2011. Subjects were followed up to age 16 years.

Much remains to be known. What are those specific genes and what are those environmental factors, important because they are likely to be modifiable. Research continues to answer those questions.

What can be inferred from the study.

– Genes being the major force, autism is largely present before birth.

– There has been a disproportionate and frequently misguided focus widely spread by media on environmental risk factors, including the false, yet enduring, belief regarding the measles, mumps, rubella vaccine, as a cause of autism.

– Recognizing early autism signs is important in order that early interventions, if needed, can be applied as early as possible.

Reference: Dan Bai, Benjamin Hon Kei Yip, Gayle C Windham. “Association of Genetic and Environmental Factors with Autism in a 5-Country Cohort”, online, July 17, 2019, JAMA Psychiatry, 1411, do1:10:1001.

WHEN HOSPITALIZED, AUTISM PATIENTS, AND FEMALES MORE, HAVE HIGHER RISK OF DEATH COMPARED TO NEUROTYPICALS

     by Lirio S. Covey, Ph.D.

A large, US-based study found that when hospitalized, adults with autism spectrum disorder (ASD) have a nearly 50 percent higher risk of death compared to the general population.

Also found was that this greater risk is about twice higher in women with ASD compared to men with ASD, and three times higher among autistic women compared to women without ASD.

It has been previously reported that autistic persons are at higher risk for illnesses than the general population; these findings suggest that this greater risk extends to mortality outcome from a hospital stay.

The analysis was controlled for potential confounders that affect mortality, including socioeconomic factors and the presence of co-occurring physical or psychiatric illness.

The study used a nationwide inpatient sample, and compared a very large number of autistic persons – 34,237, compared to 102,711 controls.

The precise source of the greater risk remains to be determined since factors that could moderate the increased risk of death, which were not measured, need to be considered. Such factors include lower quality of hospital care for autistic patients as well as the fact that the autistic persons are likely to present to the hospital in more severe states than do non-autistic persons, a condition that applies particularly for autistic women for whom autism is usually recognized at older years. Both of those potentially moderating conditions could increase risk of death, independently of the autism itself.

Importantly, these findings imply the need for more careful and aggressive health care and monitoring of persons with autism, some of whom may be unable to adequately and correctly express their medical symptoms, and improved efforts towards early detection of autism and other health symptoms in order that needed treatment is delivered in timely manner rather than delayed.

Reference: Akobirshoev I, et al. Autism. 2019 “In-hospital mortality among adults with autism spectrum disorder in the United States: A retrospective analysis of US hospital discharge data”

FINDINGS FROM A POPULATION-BASED STUDY

By Lirio S Covey, Ph.D.

The rate of depression was higher in young adults with Autism Spectrum Disorder (ASD) than in same-aged persons in the general population.

In a population-based study of young adults conducted in Sweden, the prevalence of depression was significantly higher in those with autism than in the age-comparable general population. By age 27, almost 20% (19.8%) of persons with ASD had received a diagnosis of depression compared to only 6.0% in the general population.

The study data were collected from total population registries, in this case, of children born between January 2001 and December 2011; they were followed up to the age of 27 years.

The prevalence of depression was also higher in non-autistic siblings of the index person with ASD than in the general population, a finding compatible with the putative effect of familial liability, including genetic factors, on risk for ASD. Indicating more than familial liability, that is, factors specific to ASD, the rate of depression was still higher in the index autistic person than in the non-autistic sibling.

Further, within the autistic group, the rate of depression was higher among those without intellectual disability (24%) than in those with intellectual disability (9%). A partial explanation for the difference could be that depressive symptoms were not well-recognized among those with intellectual disability and related conditions.

The researchers also noted that ascertainment of ASD after the onset of depression occurred in as many as half of the ASD individuals possibly because more attention was paid to the depressive symptoms. This delay is clinically relevant in that the masking of ASD symptoms could exacerbate the impairments due to ASD and limit access to interventions known to improve quality of life for persons with ASD.

A further implication of the observed relationship in this study of young adults is that the underlying presence of ASD should be considered when symptoms of depression are reported.

Reference:

Dheeraj Rai, MRCPsych, PhD; Hein Heuvelman, MSc, PhD; Christina Dalman, MD, PhD; Iryna Culpin, MSc, PhD; Michael Lundberg, MPH; Peter Carpenter, MBChB, FRCPsych; Cecilia Magnusson, MD, PhD. Association Between Autism Spectrum Disorders With or

Without Intellectual Disability and Depression in Young Adulthood. August 31, 2018. doi:10.1001/jamanetworkopen.2018.1465

–