Autoimmune disease has been known to increase the risk of epilepsy, but it's new knowledge that a mother's rheumatoid arthritis impacts their offspring's epilepsy risk.
When a woman of childbearing years has rheumatoid arthritis (RA), it can impact more than just herself. Physicians from the Copenhagen University Hospital in Denmark found a strong correlation between maternal RA and offspring epilepsy.
RA differs from other types of arthritis, like osteoarthritis, in the sense that it’s an autoimmune disease which causes the body’s immune system to attack the joints. Past research in The Journal of the American Medical Association (JAMA) discovered that autoimmune disease increases the odds ratio of epilepsy by 5.2 in children; but now, evidence is connecting the two starting in pregnancy.
The team analyzed a nationwide cohort including babies born from 1977 to 2008 in Denmark. The 1,917,723 children were followed for an average of 16 years. The primary thing they were keeping an eye on was the onset of epilepsy.
The 31,491 children (1.6%) who ended up developing epilepsy were categorized by age of onset:
Out of the children with epilepsy, 13,556 (0.7%) had mothers with RA — including women who were diagnosed after giving birth (“preclinical” RA).
For children who were exposed to RA in utero, their early and late childhood epilepsy risk had adjusted hazard ratios (HRs) of 1.34 and 1.26, respectively. However, the in utero RA exposure did not impact epilepsy risk in adolescence/adulthood. Overall, the child’s risk of epilepsy was higher if the mother had RA during childhood as opposed to developing the condition afterwards (HR: 1.90 and 1.26, respectively).
To look at those numbers in a different way, children were up to 90% more likely to develop epilepsy if their mothers had RA at the time of birth, compared to those who were not exposed to RA. Having a mother with preclinical RA increased the epilepsy risk by 26%, according to the report. These results held up even after adjustments were made for the baby’s birth weight, gestational age at birth, and the mother’s own epilepsy diagnosis.
A father’s RA diagnosis, however, did not have an impact on epilepsy risk at any age.
“These results suggest that changes in the environment for the fetus may play a role in the development of epilepsy,” first author, Ane Lilleore Rom, PhD, said in a news release. “We don’t know yet how this may work, but it could involve the production of maternal antibodies that could affect the unborn child.”
RA treatment may not be the cause of the offspring’s epilepsy since preclinical RA cases also increased the risk, Rom explained.
The study, “Parental rheumatoid arthritis and childhood epilepsy,” was published in the journal Neurology.