Stuttering and incident type 2 diabetes: a population-based study of 2.2 million adolescents.

Purpose To investigate the association between stuttering in adolescence and incident type 2 diabetes in young adulthood. Materials and methods This nationwide population-based study included 2,193,855 adolescents of age 16-20 years who were assessed for military service between 1980 and 2013. Diagnoses of stuttering in adolescence were confirmed by a speech-language pathologist. Diabetes status for each individual as of December 31, 2016, was determined by linkage to the Israeli National Diabetes Registry. Relationships were analysed using regression models adjusted for socioeconomic variables, cognitive performance, coexisting morbidities, and adolescent BMI. Results Analysis was stratified by sex (pinteraction=0.035). Of the 4,443 (0.4%) adolescent men with stuttering, 162 (3.7%) developed type 2 diabetes, compared to 25,678 (2.1%) men without stuttering (adjusted odds ratio 1.3, 95% CI 1.1-1.6). This relationship persisted when unaffected brothers of men with stuttering were used as the reference group (adjusted OR=1.5, 95%CI 1.01-2.2), or when the analysis included only adolescents with unimpaired health at baseline (adjusted OR=1.4, 95%CI 1.1-1.7). The association was stronger in later birth cohorts with an adjusted OR of 2.4 (1.4-4.1) for cases of type 2 diabetes before age 40. Of the 503 (0.1%) adolescent women with stuttering 7 (1.4%) developed type 2 diabetes, compared to 10,139 (1.1%) women without stuttering (OR=2.03, 95%CI 0.48-2.20). Main conclusions Adolescent stuttering is associated with an increased risk for early-onset type 2 diabetes among men.