Is high socioeconomic status a risk factor for multiple sclerosis? A systematic review

Abstract

High socioeconomic status (SES) is generally associated with better health outcomes, but some research has linked it with an increased risk of multiple sclerosis (MS). The evidence for this association is inconsistent and has not previously been systematically reviewed. A systematic review of cohort and case-control studies in any language was conducted looking at the association between MS and SES. MEDLINE and EMBASE were searched for articles in all languages published up until 23 August 2013. Twenty-one studies from 13 countries were included in the review. Heterogeneity of study settings precluded carrying out a meta-analysis, and a qualitative synthesis was performed instead. Five studies, all from more unequal countries, reported an association between high SES and MS. Thirteen studies reported no evidence of an association, and three studies reported an association with low SES. These 16 studies largely came from more egalitarian countries. The evidence for an association between high SES and increased MS risk is inconsistent but with some indication of a stronger effect in countries and time periods with higher inequality. Firm conclusions are hampered by the failure of most studies to control for other important risk factors for MS.

Geographic variations of multiple sclerosis prevalence in France: The latitude gradient is not uniform depending on the socioeconomic status of the studied population

“…If we admit that the risk of developing multiple sclerosis is determined during childhood or adolescence and is not associated with socioeconomic status by itself, 31,32 our findings support the assumption that geographic mobility for job search or for professional reasons at adulthood could influence the latitudinal gradient of prevalence for multiple sclerosis. The findings suggest that labour mobility could play a role in altering the north-south gradient that exists in France and more broadly that migrations could explain the recent observations of disappearance or decrease of the north-south gradient of multiple sclerosis in Europe and North America.…”

Environmental modifiable risk factors for multiple sclerosis: Report from the 2016 ECTRIMS focused workshop

“…14 The 'hygiene hypothesis' may explain some epidemiological findings, including a lower incidence of MS in developing countries (with poorer hygiene) as compared to countries with higher socioeconomic standards, and an increased MS prevalence associated with improving education and socioeconomic status (SES) in some early investigations, 14 although more recently the inconsistency of data surrounding SES and MS risk has been recognized. 15 This hypothesis is also corroborated by the observation of an increased risk of MS with a late age at infection with EBV and manifestation as IM. 16 However, the hypothesis does not completely fit with epidemiological MS data, since those subjects who are seronegative for EBV infection have a very low MS risk status.…”

Socio-economic factors and immigrant population studies of multiple sclerosis

“…The uneven distribution of MS in the world with the higher prevalence found in the socio‐economic better‐situated regions has mainly focused on differences in single environmental factors and less on SES. Absence of association between MS risk and SES is generally found in more egalitarian countries , but the studies are also hampered by different definitions of SES.…”