|
Page: Epidemiology
Main article
| Home > Child Health > Epidemiology |
Gender differences
There is not a clear-cut ratio of incidence between males and females. Studies have found much higher prevalence in males at the high-functioning end of the spectrum, while the ratios appear to be closer to 1:1 at the low-functioning end. In addition, a study published in 2006 suggested that males over 40 are more likely than younger males to parent a child with autism, and that the ratio of autism incidence in males and females is closer to 1:1 with older fathers.
Reported increase with time
There was a worldwide increase in reported cases of autism over the decade to 2006. There are several theories about the apparent sudden increase.
Many epidemiologists argue that the rise in the incidence of autism in the United States is largely attributable to a broadening of the diagnostic concept, reclassifications, public awareness, and the incentive to receive federally mandated services. However, some authors indicate that the existence of an as yet unidentified contributing environmental risk factor cannot be ruled out. On the other hand, a widely-cited pilot study conducted in California by the UC Davis M.I.N.D. Institute (17 October 2002), reported that the increase in autism in California is real, even after accounting for changes to diagnostic criteria.
The question of whether the rise in incidence is real or an artifact of improved diagnosis and a broader concept of autism remains controversial. Dr. Chris Johnson, a professor of pediatrics at the University of Texas Health Sciences Center at San Antonio and co-chair of the American Academy of Pediatrics Autism Expert Panel, sums up the state of the issue by saying, "There is a chance we're seeing a true rise, but right now I do not think anybody can answer that question for sure." (Newsweek reference below).
The answer to this question has significant ramifications on the direction of research, since a real increase would focus more attention (and research funding) on the search for environmental factors, while the alternative would focus more attention to genetics. On the other hand, it is conceivable that certain environmental factors (such as chemicals, infections, medicines, vaccines, diet and societal changes) may have a particular impact on people with a specific genetic constitution.
One of the more popular theories is that there is a connection between "geekdom" and autism. This is hinted, for instance, by a Wired Magazine article in 2001 entitled "The Geek Syndrome", which is a point argued by many in the autism rights movement. This article, many professionals assert, is just one example of the media's application of mental disease labels to what is actually variant normal behavior—they argue that shyness, lack of athletic ability or social skills, and intellectual interests, even when they seem unusual to others, are not in themselves signs of autism or Asperger's syndrome. Others assert that children who in the past would have simply been accepted as a little different or even labeled 'gifted' are now being labeled with mental disease diagnoses. See clinomorphism for further discussion of this issue.
Due to the recent publicity surrounding autism and autistic spectrum disorders, an increasing number of adults are choosing to seek diagnoses of high-functioning autism or Asperger's syndrome in light of symptoms they currently experience or experienced during childhood. Since the cause of autism is thought to be at least partly genetic, a proportion of these adults seek their own diagnosis specifically as follow-up to their children's diagnoses. Because autism falls into the pervasive developmental disorder category, an individual's symptoms must have been present before age seven in order to make a strict differential diagnosis.
|
Important notice:
The content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other
qualified health provider with any questions you may have regarding a medical condition.
|