Signs of a higher prevalence of autoimmune thyroiditis in female offspring of bipolar parents

Abstract

Background Studies are inconsistent as to whether patients with bipolar disorder are more frequently affected by autoimmune thyroiditis. Aim To study the prevalence of autoimmune thyroiditis in offspring of bipolar patients. Method In 1998 140 children (age 12–21 years) of bipolar parents were evaluated psychiatrically using the K-SADS-PL and blood was drawn to determine thyroperoxidase antibodies (TPO-Abs) and serum TSH. Blood samples of high school students (aged 12–19 years, n = 77) and young adults (aged 20–35 years, n = 52) were used as comparisons. At follow-up the offspring were psychiatrically evaluated and tested for TPO-Abs and TSH twice (14 months and 55 months after enrollment). Results TPO-Abs were predominantly found in female bipolar offspring, who had a significantly higher prevalence of positive TPO-Ab titers (9 out of 57 female offspring subjects) as compared to the female high school and young adult comparisons (4 out of 103 female control subjects). In TPO-Ab positive offspring ( n = 11) a raised prevalence of 55% of thyroid failure (i.e. a raised serum TSH or l-thyroxine treatment) was evident. TPO-Ab positive offspring did not show a raised prevalence of mood disorders (or any psychopathology) as compared to the TPO-Ab negative offspring. Conclusion Our study suggests that bipolar offspring are more vulnerable to develop thyroid autoimmunity independently from the vulnerability to develop psychiatric disorders.