The aim of this study was to investigate whether demographics, lifestyle, and comorbidities were associated with MCS and SBS in a large Japanese population, and whether autistic traits (Japanese version of the Autism-Spectrum Quotient Short Form, AQ-10-J), psychological distress (Japanese version of the Kessler 6-Item Psychological Distress Scale, K6), and serum total and allergen-specific immunoglobulin E (IgE) levels were related to the outcomes. This evidence concerns the gene IGHE and Abnormal emotional state.