Fatigue and its contributing factors in people with multiple sclerosis: a cross-sectional study

Fatigue is a common and debilitating symptom in people with multiple sclerosis (PwMS), yet its contributing factors are not fully understood. This study examined how fatigue severity relates to physical activity, limb function, mood, and demographics within a unified framework.

In this cross-sectional study, PwMS were recruited in Isfahan, Iran, from April 2023 to April 2024. Participants completed the Fatigue Severity Scale, and data were collected on demographics, cognitive processing speed (Symbol Digit Modalities Test), physical activity (IPAQ), upper limb function (9-Hole Peg Test), lower limb function (Timed 25-Foot Walk), depression, and anxiety (Beck inventories). Associations between fatigue severity and these factors were analyzed using stepwise linear and logistic regression models.

Among 141 participants (90.1% female; mean age: 37.87 ± 9.74 years), fatigue prevalence was 61.7%. Higher fatigue severity was significantly associated with greater depression (B (95% CI) = 0.47 (0.32, 0.63), β = 0.481), poorer lower limb function (B (95% CI) = 1.82 (0.48, 3.16), β = 0.234), progressive MS (B (95% CI) = 7.38 (1.85, 12.91), β = 0.186), and lower physical activity (B (95% CI) = -0.0006 (-0.001, -0.0001), β = -0.156). Logistic regression indicated that being married (OR (95% CI) = 3.06 (1.20, 7.80), worse lower limb function (OR (95% CI) = 1.55 (1.01, 2.37), and higher depression scores (OR (95% CI) = 1.06 (1.01, 1.10) were associated with increased odds of clinically significant fatigue.

Fatigue was common among PwMS and was independently associated with depression, reduced lower extremity function, progressive MS, lower physical activity, and marital status. These findings highlight key physical and psychological factors associated with fatigue; however, longitudinal studies are needed to establish causality.