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Research by Topic: Prevalence
This week’s ASF podcast takes a look at the prevalence rate of autism diagnoses. Two national datasets have shown no further increase in autism prevalence in the last few years of looking. Also, folic acid proves to show an effect on the probability of not just an autism diagnosis but also autism symptoms, especially important […]
What is the real prevalence of autism? It depends on how you ask the question. But however it is asked, the answer is too high. Additionally, those with autism are entering the educational system where interventions are built in an "ivory tower." Interventions need to be adapted and implemented in real world settings with real […]
Excess Mortality and Causes of Death in Autism Spectrum Disorders: A Follow Up of the 1980s Utah/UCLA Autism Epidemiologic StudyPublished May 8, 2015 in J Autism Dev Disord
This study’s purpose was to investigate mortality among individuals with Autism Spectrum Disorders (ASD) ascertained during a 1980s statewide autism prevalence study (n = 305) in relation to controls.
Should We Believe the Centers for Disease Control and Preventions Autism Spectrum Disorder Prevalence Estimates?Published July 1, 2014 in Autism: The International Journal of Research and Practice
Autism: The International Journal of Research and Practice has published an important and interesting new editorial by Dr. David Mandell and Dr. Luc Lecavalier that challenges the methods the CDC uses to collect and publish autism prevalence data, now at 1 in 68.
The CDC has released its 2014 Community Report on Autism, which gives details behind the new 1 in 68 number, as well as additional state-by-state prevalence information.
When it comes to autism prevalence, it can be difficult to separate real risks from false rumors. The topics that gain the most media coverage aren’t always the ones with the greatest affect on autism risk. The risk ratio can give perspective where isolated news stories dont.
A Higher Mutational Burden in Females Supports a Female Protective Model in Neurodevelopmental DisordersPublished February 27, 2014 in American Journal of Human Genetics
Researchers have more clues as to why more boys than girls are diagnosed with Autism Spectrum Disorder. A new study in the American Journal of Human Genetics suggests that for boys, it takes less of a genetic hit to cause autism than it does for girls. The study continues to say that when it does appear in girls, it is due to a much more severe genetic hit, usually resulting in much more severe autism symptoms.
Neurodevelopmental disabilities, including autism, attention-deficit hyperactivity disorder, dyslexia, and other cognitive impairments, affect millions of children worldwide, and some diagnoses seem to be increasing in frequency. A new study in The Lancet states that industrial chemicals that injure the developing brain are among the known causes for this rise in prevalence. Building on a 2006 study in which researchers identified five industrial chemicals as developmental neurotoxicants (lead, methylmercury, polychlorinated biphenyls, arsenic, and toluene), epidemiological studies have documented six additional developmental neurotoxicants manganese, fluoride, chlorpyrifos, dichlorodiphenyltrichloroethane, tetrachloroethylene, and the polybrominated diphenyl ethers. To protect children from exposure to such harmful chemicals, researchers say that untested chemicals should not be presumed to be safe to brain development.
A long-awaited study has confirmed the fears of Somali residents in Minneapolis that their children suffer from higher rates of a disabling form of autism compared with other children there. The study by the University of Minnesota, the Centers for Disease Control and Prevention, and the research and advocacy group Autism Speaks found high rates of autism in two populations: About one Somali child in 32 and one white child in 36 in Minneapolis were on the autism spectrum. But the Somali children were less likely than the whites to be high-functioning and more likely to have I.Q.s below 70. (The average I.Q. score is 100.) The study offered no explanation of the statistics.
Autism rates in the United Kingdom appear to have leveled off between the years 2000 and 2010 after a five-fold rate increase in the 1990s. The report, published in the journal BMJ Open, does not have any conclusive answers as to why there was such a dramatic increase in autism diagnosis in the 1990s, but it does state that any link between autism and vaccines has been ruled out. This BMJ Open report is being compared to a report released by the CDC last year that found rates of autism diagnosis in the United States increased 78 percent between 2004 and 2008.
New research from the CDC and published in the journal Developmental Medicine & Child Neurology found significantly high rates of autism among children diagnosed with cerebral palsy. Of the 147,000 children studied, seven percent of the children with cerebral palsy were also diagnosed with autism, compared to a little greater than one percent of kids who have autism in the general population.
A study by researchers with the UC Davis MIND Institute studied children with chromosome 22q11.2 deletion syndrome, who as a group have a prevalence of autism between 20 and 50 percent according to parent reports. This study found that these children may be getting misdiagnosed because the symptoms of the chromosome 22q11.2 deletion syndrome, including social impairments, are very similar to symptoms of autism.
This study found that most in vitro fertilization (IVF) procedures do not show an increase in the risk of autism. However, it found a small increase in the risk of autism in the most severe forms of male infertility that require surgical sperm retrieval.
This study examined the relationship between maternal childhood abuse and autism in children in a large population-based sample. Maternal abuse was significantly associated with increased autism risk even after researchers controlled for perinatal risk factors, including gestational diabetes, smoking during pregnancy, preeclampsia, exposure to intimate partner violence and premature birth.
Changes in Prevalence of Parent-reported Autism Spectrum Disorder in School-aged U.S. Children: 2007 to 20112012Published March 20, 2013 in CDC
This report presents data on the prevalence of diagnosed autism spectrum disorder (ASD) as reported by parents of school-aged children (ages 617 years) in 20112012. Results suggest 1 in 50 U.S. children is diagnosed with ASD based on parent report.
In effort to stimulate more research to better understand ASD trends, ASF President Alison Singer and other stakeholders discuss the increase in ASD prevalence and share their knowledge and opinions.
Autism Spectrum Disorder Reclassified: A Second Look at the 1980s Utah/UCLA Autism Epidemiologic StudyPublished January 1, 2013 in Journal of Autism and Developmental Disorders
According to this study, DSM-IV-TR criteria capture more individuals with ASD and intellectual disability than DSM III criteria. The authors examined records from a statewide epidemiological study in the 80s and found that 59% of participants who were considered not autistic in the original study likely were autistic based on current DSM criteria and clinician review methods used in CDC studies.
“We have followed up a 2002 population study of autism prevalence in 15-24-year olds in the Faroe Islands. The rate of ASD grew significantly from 0.56% in 2002 to 0.94% in 2009. Although these results are within the range of typical findings from other studies, there were some interesting details. There were-in addition to 43 originally diagnosed cases in 2002-24 newly discovered cases in 2009 and nearly half of them were females. It is possible that unfamiliarity with the clinical presentation of autism in females have played a significant role in this context. There was diagnostic stability for the overall category of ASD over time in the group diagnosed in childhood (7-16) years, but considerable variability as regards diagnostic sub-groupings.”
Results of this study show that while children of migrant parents are at an increased risk of low-functioning autism, they are at a decreased risk for high-functioning autism. Researchers call for further research to determine if environmental factors associated with migration influence the development of autism.