This study aimed to confirm whether autistic traits are normally distributed across a population and to describe their association with the sociodemographic characteristics of Japanese workers. The participants were 2075 workers aged 23-65 years from various parts of Japan. Autistic traits were measured using an abridged Japanese version of the Autism-Spectrum Quotient (AQ-Short). The AQ-Short comprises five subcomponents assessing a fascination for numbers and patterns (numbers/patterns), difficulties with imagination, a preference for routine, difficulties with social skills, and difficulties with switching attention. The five subcomponents of the autistic phenotype as well as the overall autistic phenotype itself were continuously distributed across the sample population of Japanese workers. Men had significantly higher AQ-Short scores than women. AQ-Short scores were not associated with age. Except for the numbers/patterns scores, workers of a lower socioeconomic status had significantly higher AQ-Short scores than their respective counterparts. For the numbers/patterns trait, workers of a higher socioeconomic status scored higher. Workers with low general physical activity had or tended to have higher scores for total and all subcomponent traits, except for the numbers/patterns trait. Generally, the autistic phenotype was more prevalent in workers of a low socioeconomic status, while a particular trait was prevalent among workers of a high socioeconomic status.
Keywords: autism spectrum disorder; autistic trait; distribution; health-related behaviors; socioeconomic status.