Environmental risk factors in multiple sclerosis

Abstract

The etiology of multiple sclerosis is, at present, not definitely known, but genetic and environmental factors play a role in its causation. Environmental causes have a predominant impact. Epidemiologic research has contributed considerably to the identification of external risk factors in this multifactorial setting, but methodological constraints still play a major part. Viral and other microbial agents have drawn much attention, although none of them is a necessary condition for the disease. This is true also for the Epstein-Barr virus, for which most data, including prospective data, supports a role in the majority of multiple sclerosis patients. In parallel, the hypothesis is still attractive in that it is not the virus per se, but rather more the age when it infects the human being that is the crucial matter. Other risk factors, such as tobacco smoking and vitamin D deficiency, which have immunomodulating properties, may also play some role, although the latter is not compatible with all data of the descriptive epidmiology of multiple sclerosis. Diet might be of considerable importance, all the more since multiple sclerosis can be ecologically attributed to a certain food patterns and is inversely associated with others (e.g., the 'Mediterranean diet'). The hypothesis that the preservation of meat by nitrite and wood smoke plays a role, and the protective influence of a fish and, possibly, a vegetable diet, are supported by some studies, but methodological constraints limit, at present, definite conclusions. A new avenue is the search for an interaction between genetic and environmental causes, and also between several environmental factors that might lead to new approaches for prevention and, perhaps, for the treatment of multiple sclerosis.

A Multimodal Intervention for Patients with Secondary Progressive Multiple Sclerosis: Feasibility and Effect on Fatigue

“…1,2 There is increasing interest in the development of combination therapies, using immune suppressants and drugs with distinct mechanisms of action, but side-effects limit the number of pharmacologic agents that can be safely used. [3][4][5] Combinations of nonpharmaceutical treatments that are known to increase muscle strength and positively influence brain function by multiple mechanisms of action but with minimal side-effects may provide an alternative treatment.…”

“…12,13 The number of mean daily servings of vegetables is inversely correlated with the risk of developing MS and obesity, 14 a common comorbidity. 1 Greens, sulfur-rich vegetables and brightly colored vegetables provide many dietary molecules (e.g., flavonoids, polyphenols, and thiols) with favorable impact on molecular pathways influencing MS disease activity (e.g., sirtuins, adenosine monophosphate protein kinase, nuclear transcription factor j B, and peroxime proliferatoractivated receptors) 12,13 and nutrients important to optimal brain physiology. 11,15,16 Currently, no particular diet is prescribed as a treatment for MS, but some studies suggest that changes in diet might be beneficial.…”

Multiple Sclerosis and Several Demographic Characteristics, Family History of MS, and Month of Birth: A Case-Control Study

“…Numerous studies have assessed the associations of different ethnicities and races with the risk of MS worldwide (2,12,14,25). Iran has different ethnic groups, each with specific lifestyle and behavioral habits as well as different environmental exposures.…”

“…Despite extensive research, the exact cause of MS is still unknown. Several factors have been reported as risk factors for MS, but the main causes are still unknown (2). Recent studies have indicated the main cause of MS could be a combination of genetic susceptibility and environmental exposures during pregnancy and early puberty.…”

Association of IL-10 (-1082 G/A Polymorphism) with Multiple Sclerosis Risk: A Systematic Review and Meta-Analysis

“…It is widely accepted that MS is a complex demyelinating disease and both environmental and genetic factors contributed to its susceptibility and progression (Brooks et al, 2010;Lauer, 2010;Libbey et al, 2007;Maya et al, 2008;Sospedra and Martin, 2005;Stridh et al, 2014;Williams et al, 1991;Zivadinov and Pirko, 2012). Environmental factors comprise ethnicity, age, gender, diet, family history, parent-of-origin and so on.…”