No strong link between parental mental illness and autoimmune diseases in children

Mental illness in parents carried no strong link with autoimmune disease in their offspring, but risks varied widely, according to a study published in the Journal of Psychiatric Research.

“There is increasing interest in understanding potential link between autoimmune diseases and mental illness, especially common mental disorders. Individuals who suffer from mental illness have a higher risk subsequently of developing autoimmune diseases,” Alicia Nevriana, a postdoctoral researcher at the department of global public health at the Karolinska Institute a part of the University of Solna in Sweden, and colleagues wrote.

Nevriana and colleagues conducted a population-based cohort study, which included 2,192,490 Swedish children born between 1991 and 2011, as well as 1,224,238 mothers and 1,207,810 fathers. Children were tracked from their date of birth until the earliest of either their initial emigration date, death of either parent or child, their 18th birthday or Dec. 31, 2016.

Data regarding parental mental illness was taken from the National Patient Register and defined according to ICD codes, but clinical diagnoses were defined according to DSM criteria. As such, parental mental illness was gauged based on similarities of diagnostic categories between the two and grouped into psychotic disorders and common mental disorders.

For offspring, autoimmune diseases such as type 1 diabetes, juvenile idiopathic arthritis (JIA), systemic lupus erythematosus, psoriasis, multiple sclerosis and inflammatory bowel disease were identified from inpatient/outpatient healthcare visits according to ICD codes. Associations were measured by hazard ratios (HRs) adjusted for potential confounders.

Researchers found that parental mental illness was associated with a small increase in risk of offspring autoimmune disease (HR, 1.05; 95% CI 1.021.08). However, data showed parental common mental disorder was associated with higher risk of JIA (HR 1.09 95% CI 1.011.18), psoriasis (HR 1.13 95% CI 1.061.21) and type 1 diabetes (HR type 1 diabetes, 1.11; 95% CI 1.011.22).

Maternal psychosis was associated with a reduced risk of IBD (HR, 0.68; 95% CI 0.490.95), as well as paternal alcohol/drug misuse and IBD (HR, 0.80; 95% CI 0.640.99).

Maternal eating disorders were associated with a markedly increased risk for type 1 diabetes (HR, 1.41; 95% CI 1.051.89).

“Further studies are needed to understand potential mechanisms underlying these associations, for example, by conducting familial studies to disentangle potential genetic and environmental influences,” Nevriana and colleagues wrote.