Background: Studies of siblings and twins suggest a genetic component of autism that does not fully explain its current increase. The aim is to investigate whether environmental factors such as exposure to occupational hazards (night work, handling of solvents and/or electromagnetic fields) increases the likelihood of autism spectrum disorders (ASD) in children.
Methods: Observational case control study by analyzing the records of 206 children (age between 16 and 36 months) evaluated in the Early Intervention Service of Ciudad Real (70 with ASD and 136 unaffected children). To assess the risk of ASD associated with night work, handling of solvents and/or electromagnetic fields, odds ratio (OR) were calculated with 95% confidence intervals (CI).
Results: The risk of ASD is multiplied by 2.22 when one parent works in the studied occupations (OR=2.22, 95% CI=1.42-3.48), highlighting work with solvents (OR=2.81, 95% CI=1.28-6.17) and night work (OR=2.18, 95% CI=1.21-3.93). It is multiplied by 3 if the mother's job is one of these occupations (OR=3, 95% CI=1.44-6.26), standing out night work (OR=3.47, 95% CI=1.39-8.63), and handling of solvents (OR=2.88, 95% CI=1.28-6.17); whereas it is multiplied by 1.94 if the father works in these occupations (OR=1.94, 95% CI=1.07-3.53), standing out handling of solvents (OR=2.81, 95% CI=1.01-7.86). A positive association between the educational level of parents and ASD is found.
Conclusions: The results show a significant relationship between the exposure of the parents to occupational hazards and ASD in the children, suggesting the involvement of genetic alterations caused by environmental factors in the origin of the disorder.