Center of Neurodevelopmental Disorders (KIND), Centre for Psychiatry Research; Department of Women's and Children's Health, Karolinska Institutet & Stockholm Health Care Services, Region Stockholm, Gävlegatan 22, 11330, Stockholm, Sweden.
Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Berzelius Väg 8, Solna, 17165, Stockholm, Sweden.
Mol Autism. 2023 Apr 21;14(1):17. doi: 10.1186/s13229-023-00548-3.
Autism spectrum condition and attention-deficit/hyperactivity disorder (ADHD) are associated with a range of physical health conditions. The aim of this study was to examine the etiological components contributing to co-occurring physical health conditions in autism and ADHD.
In this nationwide Child and Adolescent Twin Study in Sweden, we analyzed data from 10,347 twin pairs aged 9 and 12. Clinical diagnoses of autism, ADHD, and physical health conditions were identified through the Swedish National Patient Register. Subclinical phenotypes of autism and ADHD were defined by symptom thresholds on a standardized parent-interview, the Autism-Tics, ADHD, and Other Comorbidities inventory. Associations between physical health conditions and autism/ADHD phenotypes were examined using generalized estimating equations. Bivariate twin models were applied to estimate the extent to which genetic and environmental risk factors accounted for physical health comorbidities.
Similar patterns of association with physical health conditions were found in clinical and subclinical autism/ADHD, with odds ratios ranging from 1.31 for asthma in subclinical ADHD to 8.03 for epilepsy in clinical autism. The estimated genetic correlation (r) with epilepsy was 0.50 for clinical autism and 0.35 for subclinical autism. In addition, a modest genetic correlation was estimated between clinical autism and constipation (r = 0.31), functional diarrhea (r = 0.27) as well as mixed gastrointestinal disorders (r = 0.30). Genetic effects contributed 0.86 for mixed gastrointestinal disorders in clinical ADHD (r = 0.21). Finally, subclinical ADHD shared genetic risk factors with epilepsy, constipation, and mixed gastrointestinal disorders (r = 0.30, 0.17, and 0.17, respectively).
Importantly, since medical records from primary care were not included in the registry data used, we probably identified only more severe rather than the full range of physical health conditions. Furthermore, it needs to be considered that the higher prevalence of physical health conditions among autistic children and children with ADHD could be associated with the increased number of medical visits.
Shared genetic effects contribute significantly to autism and ADHD phenotypes with the co-occurring physical health conditions across different organ systems, including epilepsy and gastrointestinal disorders. The shared genetic liability with co-occurring physical health conditions was present across different levels of autism and ADHD symptom severity.
自闭症谱系障碍和注意力缺陷/多动障碍（ADHD）与一系列身体健康状况有关。本研究旨在探讨导致自闭症和 ADHD 同时存在的身体健康状况的病因成分。
在瑞典全国儿童和青少年双胞胎研究中，我们分析了 10347 对 9 岁和 12 岁的双胞胎的数据。自闭症、ADHD 和身体健康状况的临床诊断是通过瑞典国家患者登记处确定的。自闭症和 ADHD 的亚临床表型是通过标准化的父母访谈——自闭症-抽搐、ADHD 和其他共病清单上的症状阈值来定义的。使用广义估计方程检查身体健康状况与自闭症/ADHD 表型之间的关联。应用双变量双胞胎模型来估计遗传和环境风险因素在多大程度上导致了身体健康共病。
在亚临床 ADHD 的哮喘（比值比为 1.31）到临床自闭症的癫痫（比值比为 8.03），与身体健康状况相关的模式在临床和亚临床自闭症/ADHD 中相似。临床自闭症的遗传相关性（r）为 0.50，亚临床自闭症为 0.35。此外，在临床自闭症和便秘（r=0.31）、功能性腹泻（r=0.27）以及混合胃肠道疾病（r=0.30）之间估计了适度的遗传相关性。临床 ADHD 中混合胃肠道疾病的遗传效应贡献了 0.86（r=0.21）。最后，亚临床 ADHD 与癫痫、便秘和混合胃肠道疾病共享遗传风险因素（r=0.30、0.17 和 0.17）。
重要的是，由于登记处数据中未包括初级保健的医疗记录，因此我们可能只确定了更严重的身体健康状况，而不是全部。此外，需要考虑到自闭症儿童和 ADHD 儿童中更常见的身体健康状况可能与更多的医疗就诊次数有关。
共享的遗传效应对自闭症和 ADHD 表型以及不同器官系统的共病身体健康状况有显著贡献，包括癫痫和胃肠道疾病。在不同水平的自闭症和 ADHD 症状严重程度下，都存在与共病身体健康状况相关的共同遗传倾向。
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