The effects of the environment on autistic spectrum disorder in Jamaica

OBJECTIVE: The prevalence of autistic disorder has been rising worldwide. This disorder is believed to have a genetic basis with an environmental trigger. The clinical presentation has features that are similar to mercury poisoning, suggesting a probable environmental trigger. This paper investigates the relationship between environmental contaminants/toxins, including mercury, and autistic disorder in Jamaica. METHODS: Autistic children were identified from public and private hospital records and from records of special schools. Fifty-eight parents of autistic children completed a questionnaire about their environment and frequency of exposure to harmful chemicals and contaminants during pregnancy and prior to diagnosis. The childhood Autism Rating Scale determined the severity of autistic disorder. The relationship between the severity of autism and different environmental factors was analyzed using the chi-squared test. RESULTS: The mean±Standard Deviation age of autistic children was 6.5±3.7 years. There were 79 percent male and 21 percent female. Although there were rates of autism calculated by parish, there are no known apparent links between the geographical region and severity of autism. Sixty percent of the population had changed their address since birth. No association was found between use of common household chemicals (eg bleach, disinfectant), residence close to possible environmental contaminants (eg garbage dumps, factories, bodies of water) and autism, either during pregnancy or prior to diagnosis. A single case of exposure to mercury during pregnancy associated with severe autism was identified. CONCLUSIONS: This study was unable to identify any associations between a number of environmental agents and the severity of autism. The single case of mercury exposure during pregnancy warrants further investigation of this association with a larger sample size (AU)