Prevalence and Characteristics of Chemical Intolerance: A Japanese Population-Based Study.

Population-based cross-sectional study was performed to estimate the prevalence of chemical intolerance and to examine the characteristics of the sample. A Web-based survey was conducted that included 7,245 adults in Japan. The criteria for chemical intolerance proposed by Skovbjerg yielded a prevalence of 7.5% that was approximately consistent with that reported from a Danish population-based survey. Female gender, older age, and renovation in the house during the past 7 years were positively associated with chemical intolerance. Improvements in the condition were observed with daily ventilation habits. Medical history of atopic dermatitis, allergic rhinitis, food allergy, multiple chemical sensitivity, and depression were associated with chemical intolerance. Fatigue, depressed mood, and somatic symptoms were also positively correlated with chemical intolerance. Better elucidation of the causes, comorbidities, concomitants, and consequences of chemical intolerance has the potential to provide effective solutions for its prevention and treatment.