An Epidemiological Study of Chinese Children with Developmental Dyslexia

Objective: The epidemiological studies of Chinese developmental dyslexia (DD) in China are still limited. The current study aimed to investigate the prevalence rate, risk factors, and psychiatric comorbidities of Chinese DD in Guangzhou, a city in South China. Method: A total of 1661 students from second to fifth grades were recruited. The dyslexic students were identified by evaluating learning disability through the Pupil Rating Scale-Revised Screening for Learning Disability (PRS) scale by the head teachers and word recognition through the standard test. Students with a PRS score of <65 received the Raven's test, and those with intelligence quotient scores below 80 in the Raven's test were excluded. Psychiatric comorbidities were assessed by the Strength and Difficulties Questionnaire completed by parents. Results: The prevalence rate of Chinese DD was 4.9% in Guangzhou city. There were significant differences in gender, the paternal educational level, and reading experience before the age of 6 years between the DD group and the non-DD group. Male gender (odds ratio [OR] = 4.17), low paternal educational level (p = 0.045), and lack of reading experience before the age of 6 years (OR = 1.99) were the risk factors for DD. The DD cases had a higher risk of hyperactivity and inattention (OR = 3.21). Conclusion: This study showed that the prevalence rate of DD was 4.9% in Guangzhou city. Male gender, low paternal educational level, and lack of reading experience before the age of 6 years were the risk factors for Chinese DD. The high comorbidity rate of hyperactivity and inattention in the Chinese DD population needs further evaluation.