The story, reported by the Centers for Disease Control, is an old one: autism is still on the rise, now being diagnosed in 1 of every 68-eight-year old American children. This compares to a rate of about 1 of every 2,000 children during the 1970s and 1980s.
Much of the increase in recent decades can be attributed to greater understanding of autism and a broader definition. But the 30 percent increase from 2012 to 2014 came with no change in criteria used for diagnosis and no change in the method of collecting data. The major question is why?
A developmental disorder that develops in early childhood, autism is believed to be caused by some combination of genetic and environmental factors. Other than that there is much yet to be learned.
Many theories have been proposed, and some of the most popular have been ruled out. Autism is not a mental illness. Autism is not caused by vaccination nor any substance in vaccines. Autism is not a result of poor parenting. Autism is not caused by any specific food or types of food, although the dietary restrictions imposed by some parents may put their children at risk of nutritional deficiency.
There is no question, however, that autism spectrum disorder (ASD) is a very troubling condition. The autistic child does not interact normally with other children or adults; has problems with language and non-verbal communication; has a very limited range of interests; and is likely to display repetitive behaviors, such as rocking or hand flapping.
Two or three decades ago, many autistic children were labeled mentally retarded. Today, more than half of persons identified as autistic are average or above-average in intelligence. Some (identified as having Asperger’s syndrome) are highly intelligent and/or high functioning.
A Danish study [JAMA Pediatrics, November 3, 2014] demonstrated that about 60 percent of the increase in the number of children diagnosed can be attributed to changes in reporting and diagnostic criteria. Beginning in 1994, autism was recognized as a range of abnormalities now referred to as autistic spectrum disorder (ASD).
In 1995, health registries in Denmark started reporting diagnoses made outside hospitals, thereby including milder cases.
Similar changes also occurred in the United States, accounting for a good portion of the increase.
There is good reason, though, to question what else might be contributing to the increase. One recent study found that most–if not all–of the abnormalities in the brains of autistic children develop before the child is born–probably very early in the gestational process. These changes could be due to genetic predisposition, environmental factors affecting the mother or the internal environment of the mother.
A study published in Pediatrics found that a child born to an older mother or father had a higher risk of autistic spectrum disorders–presumably because of genetic mutations that could occur. Obesity is a growing problem throughout our culture, and there are some indications that it may affect the number of mothers giving birth to autistic spectrum children.
Several environmental factors have also come under scrutiny. Women who were exposed to pesticides during pregnancy had a higher risk of having an autistic child, according to one study. The risk was higher according to the proximity of a woman’s home to the fields and amount of pesticide used. Studies conducted both in California and North Carolina have found a link between traffic-related air pollution and the development of autism. The developing fetus is particularly vulnerable to neurotoxic substances, and there are many in the environment.
As scientists try to sort out possible causes of autism spectrum disorder, it’s important for parents and their doctors to act early to spot the signs. Even though autism spectrum disorder can be diagnosed as early as 18 months, most diagnoses come after age 4. In addition to regular developmental screening at well child visit, the American Academy of Pediatrics recommends screening specifically for ASD at 18 and 24 months.
Not all children who test positive on screens will be diagnosed with autism. But the written screening test should be followed up with an interview and, in some cases, a more comprehensive evaluation to determine if the child will benefit from a local early intervention program. With early intervention, some of the most serious effects of the disorder can be prevented.
This information was submitted by Northeastern Vermont Regional Hospital in St. Johnsbury and is meant to complement, not replace, the advice and care you receive from your healthcare provider