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Parental asthma linked to bipolar disorder in offspring

Study findings demonstrated a link between parental asthma and bipolar disorder in their children, according to data published in Schizophrenia Bulletin.

The results also showed that children aged 11 to 15 years hospitalized for asthma had higher rates of bipolar and schizophrenia spectrum disorders, but this association did not appear in children admitted before age 11 years.

“The potential association between maternal asthma and mental illness has not been widely investigated,” Joseph F. Hayes, PhD, division of psychiatry, University College London, and colleagues wrote. “As far as we are aware, only one previous longitudinal study has investigated whether schizophrenia rates were increased in the offspring of mothers with asthma, and found a weak association, which was not sustained after adjustment for parental psychiatric history.”

Researchers examined whether asthma in children and their parents was associated with bipolar and schizophrenia spectrum disorders in a longitudinal cohort study that included more than 2 million Swedish children born between 1973 and 1995. Specifically, they examined the relationships between childhood hospitalization for asthma, parental asthma before and during pregnancy and later diagnosis of bipolar and schizophrenia spectrum disorders. Children were grouped according to age of first hospital admission for asthma (aged 5 years and younger, 6 to 10 years and 11 to 15 years).

In total, 40,187 children were hospitalized with asthma before age 15 years and 9,892 were born to mothers with asthma admissions before their birth. Also, 12,705 people were diagnosed with bipolar disorder and 9,940 with schizophrenia during the follow-up period.

After adjusting for covariates, children aged 11 to 15 years admitted for asthma had increased rates of bipolar disorder (adjusted HR = 1.73; 95% CI, 1.21-2.47) and schizophrenia (aHR = 1.62; 95% CI, 1.08-2.42); but, this connection was not observed in children aged younger than 11 years. Analysis of siblings discordant for asthma showed a similar association. Maternal asthma hospitalization before birth was linked with bipolar disorder in the offspring (aHR = 1.6; 95% CI, 1.27-2.02). Furthermore, paternal asthma admission before birth was also associated with bipolar disorder (aHR = 1.44; 95% CI, 1.08–1.93). However, there was no relationship between parental asthma and schizophrenia spectrum disorders in the child.

“This study strengthens the evidence that severe asthma during adolescence increases the risk of [severe mental illness]. It suggests that there is a stronger association between parental asthma and bipolar disorder compared to schizophrenia spectrum disorders,” Hayes and colleagues wrote. “This requires further investigation, but if replicated has implications for our understanding of the differential mechanisms which are at play in the etiology of different [severe mental illness].” – by Savannah Demko

Disclosures: The authors report no relevant financial disclosures.