To assess the interaction between maternal attention-deficit/hyperactivity disorder (ADHD) history and young parental age on child's ADHD risk.
The study included 321,272 singleton children born between 1995 and 2012 from hospitals within a single integrated health care organization. The children were prospectively followed up through electronic medical record systems from birth until the first date of the following: date of clinical diagnosis of ADHD, last date of continuous health plan membership, death due to any cause, or December 31, 2017. Risks of ADHD associated with a maternal history of ADHD before pregnancy and young parental age were assessed by using Cox regression adjusting for potential confounders.
The children were followed up for a median (interquartile range) of 8.9 (6.2, 13.6) years from birth. Among them, 5.1% had ADHD diagnosis, 1.8% had a maternal history of ADHD before the pregnancy, and 4.4% had mothers <20 years and 2.3% had fathers <20 years at date of birth. The hazard ratio (HR) of ADHD in children associated with parental age <20 years varied by maternal history of ADHD (p < 0.005 for both multiplicative and additive interactions). For children without a maternal history of ADHD, the HR associated with at least 1 parent <20 years was 1.14 (95% confidence interval 1.04–1.24). However, for children with a maternal history of ADHD, the HR associated with at least 1 parent <20 years was 1.92 (95% confidence interval 1.31–2.82).
High ADHD risk in offspring associated with young parenthood was predominantly observed among children with a maternal history of ADHD.
This article has supplementary material on the web site: www.jdbp.org.
Departments of *Research & Evaluation and
†Psychiatry, Kaiser Permanente Southern California, Pasadena, CA.
Address for reprints: Anny H. Xiang, PhD, Department of Research & Evaluation, Kaiser Permanente Southern California, 100 S. Los Robles Avenue, 5th Floor, Pasadena, CA 91101; e-mail: email@example.com.
This work was partially supported by Kaiser Permanente Southern California Direct Community Benefit funds.
Disclosure: The authors declare no conflicts of interest.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.jdbp.org).
X. Wang, M.P. Martinez, T. Chow, and A.H. Xiang conceptualized and designed the study, contributed to the acquisition of data, carried out the data analyses, drafted the initial manuscript, and reviewed and revised the manuscript. J.C. Walthall and K.M. Guber contributed to the acquisition of data, analysis and interpretation of data, and critically reviewed the manuscript. All authors approved the final manuscript as submitted and agreed to be accountable for all aspects of the work.
Received May 21, 2018
Accepted February 12, 2019