Autism Rates Rising: Why?


Autism rates has risen by almost 30 percent between 2008 and 2010, according to the latest statistics by the Center for Disease Control and Prevention (CDC), and autism specialists and researchers don’t really know exactly why yet. This equates to about one child out of every 68 who are eight-years-old — or at least one child in every second and third grade classroom. The data may astound some parents and counselors who deal with autistic children regularly, and some experts have some hypothesis to explain why the rate is increasing and why autism is almost unheard of in the last generation.

One reason is that there has been an increase of awareness in autism in the general public in the last 10 years that increased the likelihood of parents to have their children checked. According to Autism Speak, a combination of better detection and identification of autism, more access to higher quality records of autism, and more exposure to certain environmental factors are the major contributors to the rising rate.  A rising number of older women having children could also be another reason, however, Autism Speak’s Chief Science Officer Rob Ring doubts that a single factor could increase the prevalence dramatically. “Some but not all of the increase may be due to increased awareness and diagnosis,” he said in a Q&A session on the company’s website. “But much of the increase remains unexplained. Science has begun to identify some of the factors that increase or decrease the chances that a child will develop autism.”

Autism isn’t just prevalent in the United States or in other Western countries. A four-year study (2005 to 2009) among over 55,000 children in the Ilsan district of Goyang, South Korea, was published in the May 2011 issue of American Journal of Psychiatry. The study consisted of mainly 7-to-12-year-old children, in which 2.64 percent of the sample population were diagnosed with autism. Overall, about two-thirds of the autistic cases were undiagnosed and untreated. This equates to about one autistic child for every 37 children in Goyang.

New methods of detection and understanding of autism and the brain can help explain why the number of cases is rising. In the latest research published in New England Journal of Medicine, researchers found “patches of disorganization” in the outer layers of the brain, specifically at the prefrontal and temporal cortical tissues. In the study, samples of brain tissues were examined from 22 children after death. Half of them had autism, half did not. Ed Lein, who is one of the researchers at Seattle’s Allen Institute for Brain Science, detected tiny patches of disrupted neuron development scattering the outer layers of the brain in autistic children. These patches are associated with higher order functions, such as understanding social cues and language. This most likely would happen during prenatal development, said Lein.

Dr. Walter Kaufmann, a neurologist at Boston Children’s Hospital who reviewed the study, said that the cause of these brain disruptions are “impossible to pin down.” However, he mentioned that the prenatal developmental stage is very susceptible to changes and interactions between genetics and the environment.



Kaufmann may have a point about how the environment of autistic children can affect their communication abilities. A recent study published in the January 2012 issue of Pediatrics found that some autistic children can outgrow their disorder’s effects. Researchers Christine Fountain, Ph.D., of Columbia University and her colleagues examined almost 7,000 children in which most were diagnosed with autism. The kids were followed from their diagnostic age to age 14 or the oldest age when the study was finished. Not all autistic kids were inept in communicating with their peers or socializing with people. At the end of the study, about 20 percent of kids were considered “bloomers” or “high-functioning,” and 25.8 percent were considered “medium-functioning” in terms of communication and social skills.  High-functioning kids with autism, which makes up about 12.7 percent of the sample, can make friends and maintain friendships, are eager to engage in social activities, and can communicate clearly with others. About 10 percent of those who started out in the low-functioning group raised themselves to the high-functioning group by age 14.

Fountain and her colleagues found that environmental factors, such as education and intellectuality of the children’s mothers and socioeconomics, can affect how autistic children develop as they approach puberty. According to the study, low-functioning children were less likely to be White and had less-educated mothers while high-functioning children were more likely to be White and had higher-educated mothers. However, among non-Whites,  Latinos had greater chances of becoming high-function than low-function. It may be possible that low-income immigrant or minority families may be receiving less appropriate health care services than more affluent and educated families.

Rahil Briggs, Ph.D., who is an assistant professor of pediatrics at Albert Einstein College of Medicine, stated that when autism is detected earlier in age in kids, there is a higher chance that they can overcome their learning and communication disabilities because the brain is very receptive to input and learning. This is why young children can learn a second language easily and why early exposure to domestic violence and abuse can have life-long damage.

Parents and families with autistic children should not feel overwhelm about why there is rising rate of autism nor should they feel helpless. Early detection and health care combined with an enriched learning environment for the children can help enhance their social skills and overcome communication problems.


By Nick Ng


New England Journal of Medicine


National Autism Association



Autism Speaks

You must be logged in to post a comment Login