Background factors of chemical intolerance and parent-child relationships

Chemical intolerance is a widespread public health problem characterized by symptoms that reportedly result from low-level exposure to chemicals. Although several studies have reported factors related to chemical intolerance in adults, the impact of family members has not been reported. In the present study, we investigated the background factors related to chemical intolerance in family members and parent-child relationships. We distributed a self-reported questionnaire to 4325 mothers who were invited to visit the Kishiwada Health Center in Kishiwada City, Osaka, between January 2006 and December 2007 for the regular health checkup of their three-and-a-half-year-old children. The prevalence of chemical intolerance in the 3-year-old children was almost one eighteenth of that reported by their mothers. Multiple logistic regression analyses revealed that cold sensitivity [odds ratio (OR), 1.89; 95% confidence interval (CI), 1.04-3.44], past bronchial asthma (OR, 2.84; 95% CI, 1.46-5.53), and any past allergies (OR, 2.21; 95% CI, 1.36-3.60) were significantly associated with chemical intolerance in the mother. The presence of indoor cat during childhood (OR, 1.99; 95% CI, 1.08-3.69) was significantly associated with chemical intolerance in the mother; however, the association was weak compared with cold sensitivity and past asthma and allergies. The current chemical intolerance of the mother was significantly associated with allergic rhinitis (OR, 2.32; 95% CI, 1.19-4.53), bronchial asthma (OR, 3.66; 95% CI, 2.00-6.69), and chronic bronchitis (OR, 3.69; 95% CI, 1.04-13.03) in her 3-year-old child. The results suggest that inherent physical constitution and childhood housing environment are associated with a risk of acquiring chemical intolerance. Children of mothers with chemical intolerance have a possible risk of respiratory hypersensitivity or inflammation. Further investigation is recommended to determine the inherent physical constitution and background environmental factors associated with the risk of acquiring chemical intolerance. The impact of having mothers with chemical intolerance on the health of children also requires further study.