The researcher and the research team investigated the prevalence of DLD and analyzed its comorbid conditions and diagnostic changes over time, using the Finnish Birth Cohorts 1987 and 1997. The results indicate that the prevalence of diagnosed DLD identified (0.29% in FBC1987; 1.10% in FBC1997) was similar to previous findings in Finland (see Kunnari et al., 2019 for a review), but lower than those in Australia (Law et al., 2017), the UK (Norbury et al., 2016), and the US (Tomblin et al., 1997) obtained through population screening. Children with DLD were at significantly increased risk of comorbid mood, behavioral and emotional and academic related disorders. Notably children with DLD were more than 16 times more likely to have developmental disorders (including academic related disorders) than their non-DLD peers. Over the course of their lives, 57.71% of individuals with DLD had one or more comorbid conditions, while 42.29% only had DLD; the conditions that tended to be diagnosed within the same age band as DLD were other speech-language disorders, motor coordination disorders, multiple developmental disorders, and behavioral and emotional disorders; and the conditions that tended to be diagnosed at a later age band than DLD were academic-related disorders and psychiatric disorders (i.e. mood disorders and neurotic disorders). The results were presented at the 12th Society for Longitudinal and Life Course Studies in October 2022 and the American Speech-Language-Hearing Association, USA in November 2022. An overview of the risk and protective factors for DLD was published in a book chapter (Laasonen & Park, 2022).
