Chemical Intolerance Is Associated with Autism Spectrum and Attention Deficit Disorders: A Five-Country...

Area of Science:

• Environmental Health
• Neurodevelopmental Disorders
• Clinical Psychology

Background:

• Chemical Intolerance (CI), Autism Spectrum Disorder (ASD), and Attention Deficit Hyperactive Disorder (ADHD) are conditions with increasing prevalence.
• Genetic and environmental factors are recognized as contributors to these conditions.
• Prior research indicates a co-occurrence of CI, ASD, and ADHD.

Purpose of the Study:

• To investigate the association between self-reported Chemical Intolerance (CI) and the likelihood of having children diagnosed with Autism Spectrum Disorder (ASD) or Attention Deficit Hyperactive Disorder (ADHD).
• To explore these associations in an international context.

Main Methods:

• A five-country international survey of 5000 participants was conducted.
• Self-reported data on CI, and parental reports of ASD and ADHD in children were collected.
• Generalized linear models and logistic regression analyses were used to estimate Odds Ratios (OR) and assess associations.

Main Results:

• High levels of CI were significantly associated with greater odds of reporting a child with ASD and ADHD in most surveyed countries, excluding Japan.
• Countries like Italy, India, and the USA showed more than double the odds of reporting a child with ASD among individuals with high CI.
• Similar associations were observed between high CI and ADHD diagnoses.

Conclusions:

• The findings align with previous U.S. studies, suggesting a link between CI and the reporting of ASD and ADHD in women.
• Cross-cultural prevalence estimates for ASD and ADHD derived from this survey methodology have serious limitations and should not be interpreted as epidemiologic rates.
• This study demonstrates an association but does not infer a causal relationship between CI and these neurodevelopmental conditions.