The Association between Dairy Consumption and the Risk of Developing Multiple Sclerosis: A Systematic Review and Meta-Analysis

Behnaz  Sedighi; Simin  Jafari; Shoboo  Rahmati; Fatemeh  Ajam; Seyedeh Tahereh  Afrah; Simin  Salehinejad; Mahdieh  Mirzaie; Roya Amir  Gooshki; Parya Jangipour  Afshar

doi:10.18502/ijph.v54i11.20386

Behnaz Sedighi Neurology Research Center, Kerman University of Medical Sciences, Kerman, Iran
Simin Jafari Neurology Research Center, Kerman University of Medical Sciences, Kerman, Iran
Shoboo Rahmati Social Determinants of Health Research Center, Research Institute for Health Development, Kurdistan University of Medical Scienc-es, Sanandaj, Iran
Fatemeh Ajam Department of Biostatistics and Epidemiology, Faculty of Public Health. Kerman University of Medical Sciences, Kerman, Iran
Seyedeh Tahereh Afrah Department of Biostatistics and Epidemiology, Faculty of Public Health. Kerman University of Medical Sciences, Kerman, Iran
Simin Salehinejad Research Center of Tropical and Infectious Diseases, Kerman University of Medical Sciences, Kerman, Iran
Mahdieh Mirzaie Department of Biostatistics and Epidemiology, Faculty of Public Health. Kerman University of Medical Sciences, Kerman, Iran
Roya Amir Gooshki Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
Parya Jangipour Afshar HIV/STI Surveillance Research Center, and WHO Collaborating Center for HIV Surveillance, Institute for Futures Studies in Health, Kerman University of Medical Sciences, Kerman, Iran

DOI: https://doi.org/10.18502/ijph.v54i11.20386

Keywords: Dairy products; Cow milk; Multiple sclerosis; Meta-analysisDairy products; Cow milk; Multiple sclerosis; Meta-analysis

Abstract

Background: Multiple sclerosis (MS) is a chronic and disabling disease that commonly affects young adults. We aimed to provide a comprehensive review of the current literature on the association between dairy consumption, particularly cow milk, and the risk of developing MS.

Methods: This systematic review and meta-analysis was conducted in accordance with PRISMA guidelines. We searched PubMed, Web of Science, Cochrane Library, and Scopus for peer-reviewed papers published until 2024. Eligible studies included randomized controlled trials, quasi-experimental studies, and observational designs (case-control, cohort, cross-sectional). Studies were excluded if they did not report sufficient data to calculate effect sizes. Study quality was assessed using the Newcastle-Ottawa Scale (NOS). A random-effects meta-analysis was conducted, and heterogeneity was assessed using the I² statistic.

Results: Twenty studies met the inclusion criteria. The overall pooled odds ratio (OR) for the association between total dairy consumption and MS risk was 0.96 (95% CI: 0.93–0.99), indicating a weak but statistically significant inverse association. Subgroup analysis of cohort studies, however, showed no significant association (relative risk [RR] = 1.18, 95% CI: 0.95–1.47, P = 0.41). Furthermore, cow's milk consumption alone was not significantly associated with MS development (OR = 0.88, 95% CI: 0.46–1.69, P = 0.21).

Conclusion: Although pooled results suggest a slight protective effect of overall dairy consumption on MS risk, findings remain inconsistent and inconclusive, especially when considering specific dairy products and study design. Additional longitudinal studies with rigorous methodology are needed to clarify the potential role of dairy in MS pathogenesis.