The risk of schizophrenia and child psychiatric disorders in offspring of mothers with lung cancer and other types of cancer: a Danish nationwide register study.
BACKGROUND
Maternal immune responses and brain-reactive antibodies have been proposed as possible causal mechanisms for schizophrenia and some child psychiatric disorders. According to this hypothesis maternal antibodies may cross the placenta and interact with the developing CNS of the fetus causing future neurodevelopmental disorders. Therefore, we investigated if children of mothers with cancer might be at higher risk of developing psychiatric disorders, with particular focus on small-cell lung cancer, which is known to induce production of antibodies binding to CNS elements.


METHODS
Nationwide population-based registers were linked, including the Danish Psychiatric Central Register and The Danish Cancer Registry. Data were analyzed as a cohort study using survival analysis techniques. Incidence rate ratios (IRRs) and accompanying 95% confidence intervals (CIs) were used as measures of relative risk.


RESULTS
In general, parental cancer was not associated with schizophrenia in the offspring (IRR, 0.98; 95% CI, 0.95-1.01). Furthermore, we found no temporal associations with maternal cancer in general; neither around the pregnancy period. However, maternal small-cell lung cancer increased the risk of early-onset schizophrenia and maternal small-cell lung cancer diagnosed within 20 years after childbirth increased the risk of schizophrenia. Parental cancer was not associated with child psychiatric disorders (IRR, 1.01; 95% CI, 0.98-1.05) except for the smoking related cancers. There was a significantly increased risk of child psychiatric disorders in offspring of both mothers (IRR, 1.35; 95% CI, 1.16-1.58) and fathers (IRR, 1.47; 95% CI, 1.30-1.66) with lung cancer of all types.


CONCLUSIONS
In general, parental cancer did not increase the risk of schizophrenia nor of child psychiatric disorders. However, maternal small-cell lung cancer increased the risk of schizophrenia in subgroups; and lung cancer in general increased the risk of child psychiatric disorders, which could be due to risk factors associated with parental smoking.
National Centre for Register-Based Research, Aarhus University, Aarhus, Denmark ; Mental Health Centre Copenhagen, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark ; The Lundbeck Foundation Initiative for Integrative Psychiatric Research, iPSYCH, Aarhus, Denmark.
Michael Eriksen
ME
Benros
Thomas Munk
TM
Laursen
Susanne Oksbjerg
SO
Dalton
Merete
M
Nordentoft
Preben Bo
PB
Mortensen
D002648:Child; D003718:Denmark / Q000453:epidemiology; D005220:Fathers; D005260:Female; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008175:Lung Neoplasms / Q000150:complications*; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology* / Q000209:etiology; D009035:Mothers; D009369:Neoplasms / Q000150:complications; D011247:Pregnancy; D011252:Pregnancy Complications, Neoplastic; D012042:Registries / Q000706:statistics & numerical data; D018570:Risk Assessment / Q000379:methods / Q000706:statistics & numerical data; D012307:Risk Factors; D012559:Schizophrenia / Q000453:epidemiology* / Q000209:etiology; D013997:Time Factors