The risk of autism is related to when and where the grandparents lived

summary: The place and time of birth of the grandparents and fathers of the children can contribute to an increased risk of autism in their offspring.

Source: University of Utah

When and where are often vital clues for epidemiologists, the medical investigators who help solve fundamental mysteries of the disease. The technique dates back at least to 19th century London, where a doctor named John Snow mapped cholera deaths and traced the source of an outbreak to a single well in the city. Once the well is closed, the epidemic is over.

Taking this idea to a new level, health scientists at the University of Utah, using a unique combination of geographic and demographic data, recently concluded that when and where the parents and grandparents of Utah children were born and raised could contribute to an increased risk of autism among their children. offspring.

The scientists believe that this new approach can be used to explore the temporal and spatial aspects of any disease for which family genealogical information is available.

The study published in International Journal of Geohealthis among the first to assess the effect of time and place (time and place) across generations on increased risk of autism.

Over time, the researchers say, this finding could lead to identifying environmental factors, such as exposure to pollutants, that can have devastating effects on genetic information passed down between generations.

says James Vanderlis, an environmental epidemiologist in the Department of Public Health at U of U Health and senior author of the study.

“Knowing that the parents and grandparents of these children with autism share space and time brings us closer to understanding the environmental factors that may have influenced this health outcome.”

Cross-generational epidemiological studies are difficult and time-consuming, says Rebecca Richards Steed, the study’s principal investigator and graduate student in the University of Utah’s Department of Geography. In fact, most of these studies have been done in animals, which reproduce rapidly and can be followed for several generations in a shorter period of time than in humans.

Using existing technology in a novel way, VanDerslice and Richards-Steed circumvented this drawback by looking at existing data available for parents and grandparents to identify places and time periods that might be associated with risk factors that increased the risk of developing the disease in later generations.

Researchers used the Utah Autism and Developmental Disabilities Registry, in conjunction with the Utah Population Database (UPDB), to identify the parents and grandparents of children born between 1989 and 2014 who have autism.

Birth certificates, driver’s license information, censuses, and medical records in the UPDB have helped scientists track when and where these individuals lived over time. UPDB is one of the few databases worldwide that includes this type of information.

For comparison, they randomly selected the parents and grandparents of children in the UPDB database who had not been diagnosed with autism. The names of the individuals have been withheld from the researchers.

In all, VanDerslice and his colleagues identified where 7,900 parents and 31,600 grandparents were born and raised. They identified 20 major groups or agglomerations scattered across the state. After analysis, 13 of the 20 groups — nine among grandparents and four among parents — were associated with a higher risk of autism in their children or grandchildren. In particular, the descendants of paternal great-grandparents were three times more likely to be diagnosed with autism than would be expected.

“What we’ve been seeing fits with the current scientific understanding of how paternal genetics is key to evolutionary change and adaptation,” says Richards-Stead. “Therefore, it is entirely possible that in autism the signal, shaped in part by environmental experiences, comes from the paternal line, which is passed on through the family.”

Seven groups, all in rural areas, had a low risk of the association between autism and family lineage.

“We’re not really sure why in some rural areas there might be what you might call a protective effect,” says Richards-Stad. “It is certainly possible that parents and grandparents living in urban areas had different environmental experiences or experiences.”

“What we can say, based on our findings, is that what we’re exposed to now is probably not only affecting us or even our children, but it’s probably also affecting our children.”

This indicates the basic building blocks
The scientists believe that this new approach can be used to explore the temporal and spatial aspects of any disease for which family genealogical information is available. The image is in the public domain

Moving forward, the researchers will delve into factors, including lifestyle, that could help explain these findings.

“Evidence shows that our environment has an inevitable effect on our growth and development, including the germ cells we carry on to the next generation,” says VanDerslice.

“Examining the shared space and time shared by our ancestors may give us clues about environmental factors that may lead to biological changes that increase disease risk in future generations.”

See also

This shows a schematic diagram of the study

Scientists believe this new approach can be used to explore temporal and spatial aspects of other conditions where family genealogical information is available.

“This idea is not exclusive to autism,” says Richards Steed. “It could be applied to any disease and could enhance our ability to understand how a confluence of genetic and environmental factors can lead to long-term health consequences for families.”

About this search for autism news

author: press office
Source: University of Utah
Contact: Press Office – University of Utah
picture: The image is in the public domain

Original search: open access.
Evidence for transgenerational effects on autism spectrum disorder using multigenerational spacetime cluster discoveryWritten by Rebecca Richards Steed et al. International Journal of Geohealth


Evidence for transgenerational effects on autism spectrum disorder using multigenerational spacetime cluster discovery


The risks of epigenetic inheritance across generations associated with complex health outcomes, such as autism spectrum disorder (ASD), have attracted increasing attention. Transgenerational exposures to environmental hazards with potential for epigenetic effects can be effectively identified using space-time clustering. Applied to ancestors of individuals with particularly poor disease outcome, who are characterized by poor developmental stages of development, space-time clustering can provide a measure of the relative risks of disease outcome in the descendants.


(1) Identification of space-time groups of ancestors with descendants with a clinical diagnosis of ASD and matched controls. (2) identification of developmental windows for ancestors with higher relative risk of autism spectrum disorder in descendants. (3) determine how relative risks may vary through the maternal or paternal line.


Family lineages associated with the residential locations of ASD cases in Utah were used to determine temporal and spatial groups of ancestors. Control family pedigrees of any cases based on age and sex were matched with cases 2:1. Data were categorized by maternal or paternal ratios at birth, childhood and adolescence. A total of 3957 children, both parents, and maternal and paternal grandparents, were identified. The Bernoulli statistic of binomial relative risk (RR) was used to select groups. Monte Carlo simulation was used to test statistical significance.


Twenty statistically significant groups were identified. Thirteen RR (>1.0) increased space-time groups were identified from the maternal and paternal strains with a p value <0.05. Paternal grandparents carried the greatest relative risk (2.86–2.96) during birth and childhood in the 1950s and 1960s, which represent the smaller populations, and occur in urban areas. In addition, seven statistically significant cohorts with RR < 1 were relatively large in area, covering more rural areas of the state.


This study identified statistically significant space-time clusters during critical developmental windows associated with ASD risk in grandchildren. The family of groups of geographic time and place is similar with more than 3 generations, which we refer to as a person geographical legacy, is a powerful tool for studying transgenerational effects that may be genetic in nature. Our new use of space-time clustering can be applied to any disease for which family pedigree data are available.

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