A large Swedish study found that early-life infection and lifestyle factors were associated with the likelihood of maintaining a benign course of multiple sclerosis 15 years after disease onset.
Patients who had infectious mononucleosis (IM) in early life, higher body mass index (BMI) at age 20 years, or infrequent fish consumption were less likely to have a benign form of multiple sclerosis (MS). In contrast, those who ate fish weekly were more likely to have a milder disease trajectory.
Benign MS was defined as an Expanded Disability Status Scale (EDSS) score of 3 or lower after at least 15 years of disease duration. Among 6,323 patients in the analysis, 2,040 had benign MS and 4,283 had non-benign MS. Patients with benign MS tended to have earlier symptom onset and were less likely to receive high-efficacy therapy during the first 15 years.
Researchers analyzed data from two nationwide Swedish cohorts—the Epidemiological Investigation of Multiple Sclerosis and Genes and Environment in Multiple Sclerosis—to evaluate pre-onset exposures. Information on BMI, infection history, smoking, sun exposure, and diet was collected retrospectively. Logistic regression estimated odds of benign MS after 15 years, while Cox regression assessed factors influencing transition to non-benign MS. Adjustments were adjusted for age, sex, ancestry, and treatment exposure.
The authors reported that IM, excess weight, and low fish intake were related to long-term disability patterns but noted that causality could not be inferred. They acknowledged that self-reported lifestyle information may introduce recall bias and that EDSS alone might not capture cognitive or mild functional impairment.
“The probability of a benign disease course in MS was associated with a history of IM and modifiable lifestyle factors,” said corresponding author, Jie Guo, PhD, of the College of Veterinary Medicine, China Agricultural University, Beijing, and the Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden, and colleagues.
The authors concluded that early-life infections and lifestyle factors may have lasting effects on MS trajectories. The researchers suggested that modifiable behaviors such as maintaining a healthy weight and balanced diet could inform preventive or management strategies. Further studies are warranted to elucidate biological mechanisms connecting early exposures with long-term disease course.
Full disclosures can be found in the published study.
