Auto-Immune Diseases, Head and Neck Trauma, and Smoking Are Strong Predictors of Multiple Sclerosis.

Background: Several health, environmental, and lifestyle-related factors have been separately linked to multiple sclerosis (MS) by different studies. However, these studies did not adequately account for the temporal association of these factors with MS while considering the influence of other variables in the analysis. A comprehensive investigation of these factors remains scarce.

Methods: A hospital-based case-control study was carried out between Jun 2020 to Mar 2021 on 525 cases and 1050 controls frequently matched by age and sex. Cases and controls were selected at the same time and from the same centers (Motahari and Imam Reza referral centers) in Shiraz (the capital of Fars Province). Health, socio-demographic, and lifestyle status during adolescence were studied in this case-control study.

Results: The likelihood of having a history of autoimmune disease(s) (OR_yes/no=15.67, P<0.001) and family history of MS (OR_yes/no=11.57, P<0.001) were higher in cases. In addition, the likelihoods of reporting a history of head/neck traumas (OR_{having a history/no history}=9.16, P<0.001), smoking (OR_{regular/other} =2.24, P=0.008), and stressful events (OR_yes/no=1.47, P=0.007) were higher among the case group. On the other hand, the odds of sun exposure (OR_{most the time/seldom} =0.14, P<0.001), physical activity (OR_{active/inactive}=0.45, P<0.001), and good quality sleep (OR=0.93, P<0.001) were significantly lower in the case group.

Conclusion: This study provided a broad picture of the factors associated with MS, most of which were modifiable. Positive alterations to these factors through social and health educational programs are likely to reduce the burden of MS in Iran.