Legg-Calvé-Perthes disease and the risk of ADHD, depression, and mortality: A registry study involving 4057 individuals

Background and purpose — Hyperactive behavior pattern (such as attention deficit hyperactivity disorder (ADHD)) is proposed to be present in individuals with Legg-Calve-Perthes disease (LCPD). We investigated whether individuals with LCPD have a higher risk of ADHD, depression, and mortality. Subjects and methods — We identified 4,057 individuals with LCPD in Sweden during the period 1964–2011. 40,570 individuals without LCPD were randomly selected from the Swedish general population and matched by year of birth, sex, and region (control group). We used Cox proportional hazard regression to estimate the relative risks. Results — Compared to the control group, individuals with LCPD had a raised hazard ratio (HR) of 1.5 (95% CI: 1.2–1.9) for ADHD. The risks were higher for female individuals (HR = 2.1, CI: 1.3–3.5) than for male individuals (HR = 1.4, CI: 1.1–1.8). Individuals with LCPD had a modestly higher hazard ratio for depression (HR = 1.3, CI: 1.1–1.5) than the control group. Furthermore, individuals...