Background: Many patients with multiple sclerosis (MS) endure cognitive impairment, which affects their everyday life and lowers their life quality. It has been demonstrated that obesity can result in poor cognitive performance in healthy individuals through various mechanisms. Therefore, we aimed at assessing the association between body mass index (BMI) and cognitive function in MS patients, using minimal assessment of cognitive functions in MS (MACFIMS) battery.

Methods: This study included eighty-one patients with relapsing-remitting MS (RRMS). After collecting the demographic data, patients' height and weight were measured in order to calculate BMI. Then, MACFIMS battery was administered in one session, after obtaining information using expanded disability status scale (EDSS).

Results: Paced Auditory Serial Addition Test (PASAT) and Symbol Digit Modalities Test (SDMT) scores were negatively correlated with BMI (P values are equal to 0.005 and 0.037, respectively). PASAT score correlated with BMI after controlling for sex, age, and EDSS, but SDMT score did not correlate. Nevertheless, no significant variation was observed in the BMI level among individuals having MS with or without cognitive deficit.

Conclusions: We have shown that, BMI is associated with poor cognitive performance in some tests which, MACFIMS battery was included. This could suggest that obesity might be an important factor, which have effect on the cognitive performance.