A study found that genetic predisposition to multiple sclerosis interacted with environmental risk factors in childhood brain development.

The research, published in the Journal of Neurology, Neurosurgery & Psychiatry and conducted at Erasmus Medical Center, examined brain magnetic resonance imaging data from 5,350 pediatric patients with volumetric scans and 5,649 with diffusion tensor imaging scans.

The data showed that patients with higher genetic risk for multiple sclerosis (MS) who were exposed to household smoking had lower total brain volume (β = −0.21, P = .025) and lower thalamic volumes (β = −0.22, P = .003). The study also found that those with higher genetic risk who tested positive for Epstein-Barr virus (EBV) demonstrated higher anti-EBV viral capsid antigen (VCA) antibody levels (β = 0.15, P = 2.98×10−6).

Investigators analyzed environmental factors including EBV serology, vitamin D status, body mass index, outdoor activities, and household parental smoking at age 5 years, along with genetic data including polygenic risk scores.

Among the 2,817 participants with volumetric data and 2,970 with diffusion imaging data, higher MS polygenic risk scores correlated with lower subcortical gray matter volume (β = −0.03, P = .014).

The MS severity genetic variant rs10191329 showed no statistically significant associations with brain outcomes in the study population.

Study limitations included an underrepresentation of participants from lower socioeconomic backgrounds. The unique study design prevented replication of the findings.

The Dutch MS Research Foundation funded the research, which was conducted as part of the Generation R Study, supported by Erasmus MC, Rotterdam, Erasmus University Rotterdam, and the Netherlands Organization for Health Research and Development.

Potential conflict of interest disclosures can be found in the study.