The purpose of this study was to assess the validity of the diagnosis of childhood autism in the Danish Psychiatric Central Register (DPCR) by reviewing medical records from 499 of 504 total children with childhood autism born 1990-1999. Based on review of abstracted behaviors recorded in case records from child psychiatric hospitals, case status determination was performed using a standardized coding scheme. In 499 children diagnosed with childhood autism in the DPCR, the diagnosis could be confirmed in 469 children (94%). Of the 30 non-confirmed cases, five were classified by the reviewers as non-autistic cases and the remaining 25 cases were either classified with another ASD diagnosis or the specific diagnosis was not possible to determine.

PURPOSE-We sought to study the possible association between parental age and autism spectrum disorder (ASD) by using both a cohort design and a sibling design. RESULTS-A total of 9556 children were diagnosed with an ASD. Both maternal and paternal age were associated with a greater risk of ASD in the offspring (hazard ratios ranging from 1.21 (1.10-1.34) to 1.65 (1.09-2.48) depending on combinations of parental age categories; <35, 35-39, and 40+ years). For mothers younger than 35 years, the risk of ASD increased with increasing father's age group. For fathers younger than 35 years, the risk of ASD increased with increasing maternal age. CONCLUSIONS-We found an association between parental age and ASD in the cohort study, but the combined underlying mechanisms through which paternal and maternal age impact ASD risk do not seem to act synergistically. The results of the sibling analysis suggest that the association between parental age and ASD found in the cohort study cannot be accounted for by common genetic and environmental factors. METHODS-Our

IMPORTANCE Increased mortality has been reported among persons with autism spectrum disorder (ASD), especially among those who also have the comorbid condition of epilepsy or intellectual disability. The effects of psychiatric and neurologic comorbidity on mortality among persons with ASD have not been rigorously examined in large, population-based studies. OBJECTIVE To investigate the mortality patterns among persons with ASD overall and to assess the associations of comorbid mental, behavioral, and neurologic disorders with mortality among persons with ASD. DESIGN, SETTING, AND PARTICIPANTS Longitudinal cohort study of children born in Denmark during the period from 1980 to 2010 who were alive at 1.5 years of age and followed up through 2013. This population-based sample of children (N = 1 912 904) was identified via linkage between the Danish Civil Registration Service and the Danish Medical Birth Register using a unique 10-digit identifier assigned to all live births and new residents in Denmark. Children were followed up for diagnoses of ASD (International Classification of Diseases, Eighth Revision [ICD-8] codes 299.00, 299.01, 299.02, and 299.03 and ICD-10 codes F84.0, F84.1, F84.5, F84.8, and F84.9) and other mental/behavioral disorders (ICD-8 codes 290-315 and ICD-10 codes F00-F99) in the Danish Psychiatric Central Research Register and for diagnoses of neurologic disorders (ICD-8 codes 320-359 and ICD-10 codes G00-G99) in the Danish National Patient Register. Data analysis was performed in December 2014. MAIN OUTCOMES AND MEASURES Deaths and causes of death among cohort members were identified via the Danish Civil Registration Service and the Danish Cause of Death Register, respectively. Regressions analyses were performed using Cox regression. RESULTS Of the 1 912 904 persons included in our study, 20 492 (1.1%) had ASD (15 901 [77.6%] were male). Of the 20 492 persons with ASD, 68 died (0.3%) (57 of 68 [83.8%] had comorbid mental/behavioral or neurologic disorders). The adjusted hazard ratio (aHR) for overall mortality was 2.0 (95% CI, 1.5-2.8) for ASD. The aHRs for ASD-associated mortality among cohort members who did not have neurologic (2.0 [95% CI, 1.4-3.0]) or other mental/behavioral disorders (1.7 [95% CI, 1.0-3.1]) were similar. The co-occurrence of ASD added no additional mortality risk for persons with neurologic (aHR, 0.7 [95% CI, 0.4-1.3]) or mental/behavioral disorders (aHR, 0.8 [95% CI, 0.5-1.2]) compared with persons with these disorders and no ASD. CONCLUSIONS AND RELEVANCE The mortality risk was 2-fold higher through young adulthood for persons with ASD than for persons without ASD, although mortality affected only 0.3% of persons with ASD. The mechanisms underlying ASD-associated mortality may be mediated through or shared with neurologic or mental/behavioral disorders, thereby providing insights into their potential neurobiological links. Health care professionals and family members should recognize the importance of these disorders with regard to the mortality risk for persons with ...

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The increasing recognition of the benefits of early intervention for children with autism spectrum disorder (ASD) stresses the importance of early identification of children who might benefit from those programs. However, in the early years of life it may be difficult to distinguish children with ASD from children with other developmental disorders. The aim of the present study was to identify behavioural patterns that could facilitate this differentiation. Prior to diagnostic assessment, 2- and 3-year-old children (n=30), all referred to a clinic for "possible autism", were observed in a semi-structured play interaction, and their parents were interviewed about the children's early development from 0 to 24 months. Following diagnostic assessment, the 17 children fulfilling the ICD-10 criteria for ASD were compared to the 13 children diagnosed with other developmental disorders (outside the autism spectrum). On the basis of parent reports only a few distinguishing signs of ASD were found before 24 months of age. On the basis of professional observations in a semi-structured play interaction several distinguishing signs were found for the 2- and 3-year-olds; smiles in response, responds to name, follows pointing, looks to "read" faces, initiates requesting verbal and nonverbal behaviours, and functional play.