Svend Erik Mouridsen1, Bente Rich2,3, Torben Isager4. 1. Bispebjerg University Hospital, Copenhagen, Denmark Svend.Erik.Mouridsen@regionh.dk. 2. Hødersvej 5, Roskilde, Denmark. 3. International Rehabilitation Council for Torture Victims, Copenhagen, Denmark. 4. Glostrup University Hospital, Denmark.
Abstract
OBJECTIVE: It has been suggested that high levels of prenatal testosterone exposure are implied in the etiology of male preponderance disorders such as autism spectrum disorder and ADHD. Within this scope, we studied the sex ratio (proportion of males) in siblings of individuals diagnosed with ADHD in childhood and adolescence. METHOD: We did a nationwide, register-based cohort study of the sex ratio in siblings of the 16,381 patients in Denmark diagnosed with ADHD at age 17 years and younger and registered in the nationwide Danish Psychiatric Central Register between January 1, 1994 and May 28, 2013. RESULTS: Among the 33,151 siblings, 17,041 were males and 16,110 females. This yields a sex ratio of 0.514, which is not statistically significant different from the Danish live birth sex ratio of 0.513 during the relevant years (p = .70). CONCLUSION: These findings provide no support for the hypothesis that the sex ratio is elevated among the siblings of people with ADHD.
OBJECTIVE: It has been suggested that high levels of prenatal testosterone exposure are implied in the etiology of male preponderance disorders such as autism spectrum disorder and ADHD. Within this scope, we studied the sex ratio (proportion of males) in siblings of individuals diagnosed with ADHD in childhood and adolescence. METHOD: We did a nationwide, register-based cohort study of the sex ratio in siblings of the 16,381 patients in Denmark diagnosed with ADHD at age 17 years and younger and registered in the nationwide Danish Psychiatric Central Register between January 1, 1994 and May 28, 2013. RESULTS: Among the 33,151 siblings, 17,041 were males and 16,110 females. This yields a sex ratio of 0.514, which is not statistically significant different from the Danish live birth sex ratio of 0.513 during the relevant years (p = .70). CONCLUSION: These findings provide no support for the hypothesis that the sex ratio is elevated among the siblings of people with ADHD.