Multiple-Community-Based Epidemiological Study of Stuttering among 3-Year-Old Children in Japan.

ABSTRACT

INTRODUCTION: Many epidemiological studies of the disorder of stuttering have been conducted during the 20th century, continuing during the current one. Unfortunately, only a few were carried out in Japan. This study aimed at assessing (1) the incidence and prevalence of stuttering in 3-year-old children in multiple Japanese communities and (2) factors associated with the onset of stuttering among these children. METHODS: A questionnaire aimed at screening for the presence of stuttering was employed for 2,055 children aged 3 years, who underwent a standard nationwide health checkup. Positive responses were confirmed in several ways (1) direct interviews and assessment of the child's speech, (2) confirmatory questionnaire, or (3) telephone interviews by licensed Speech Language Hearing Therapists. RESULTS: Approximately 6.5% of the children were found to exhibit stuttering at the time of their health checkup. This figure rose to 8.9% after including individuals who previously, but not currently, were reported to have exhibited stuttering. Among the putative risk factors, higher stuttering odds (odds ratio, OR = 3.27) were detected in those with a family history of stuttering, those whose guardians had concerns about their child's development (OR = 1.75), and those with diagnosed diseases or disabilities (OR = 2.13). DISCUSSION/CONCLUSIONS: It was concluded that, in Japan, both the risk of stuttering incidence (8.9%) in children up to, and including, the age of 3 years, as well as its prevalence (6.5%) in this population, was similar to those reported by recent studies in other countries. Additionally, our findings also confirmed that an increased risk for stuttering at age 3 is associated with a family history of stuttering.