Supplementary Material for: The role of dietary and lifestyle factors in multiple sclerosis risk in a middle eastern country: A case-control study

Background: Multiple Sclerosis (MS) is a chronic neurological disorder that primarily affects young adults and is characterized by inflammation of the central nervous system. Although genetic, immunological, and environmental factors contribute to MS risk, the role of diet remains underexplored in the Kuwaiti population. This case-control study evaluated the dietary and lifestyle factors associated with MS risk in Kuwait. Methods: A total of 152 confirmed MS cases, diagnosed according to the revised McDonald criteria, and 279 controls were enrolled from private hospitals and a public office setting. Data on demographics, medical history, sun exposure, physical activity, supplement use, and dietary intake were collected using a structured electronic questionnaire. Nutrient intake was estimated using food frequency data and nutrient databases. Multivariable logistic regression was used to identify dietary and lifestyle factors independently and significantly (p < 0.05) associated with MS risk. Results: Compared with controls, MS cases were more likely to be Kuwaiti nationals (adjusted OR = 7.85, 95% CI: 2.85–21.60), have lifelong history of obesity (adjusted OR = 3.12, 95% CI: 1.34–7.25), and exceed recommended sodium intake (adjusted OR = 5.05, 95% CI: 2.22–11.51). MS cases also showed inadequate vitamin C intake (adjusted OR = 3.45, 95% CI: 1.64–7.27), irregular vitamin D supplement use (adjusted OR = 0.27, 95% CI: 0.14–0.54), and insufficient vitamin B2 intake (adjusted OR = 2.25, 95% CI: 1.05–4.83). Regular light physical activity (≥ 3 times per week) was associated with significantly reduced MS risk (adjusted OR = 0.23, 95% CI: 0.10–0.53). Conclusion: This study identified high sodium intake, inadequate vitamin B2 consumption, and obesity as significant risk factors for MS, while regular light physical activity appeared to lower MS risk. Public health initiatives addressing these factors may help reduce MS risk in Kuwait and other similar settings. Future studies are needed to confirm these findings.