Access and Cost of Neurologic Health Care May Provide a Link Between MS and Latitude

According to new research published in Neurology, the correlation between lower incidence of multiple sclerosis (MS) diagnosis and distance from the equator may be due to issues of access to care rather than biologic mechanisms of disease. 

The study results suggest underestimated MS rates result from having less access to neurologists with equipment (ie, MRI scanners and other medical resources) and expertise needed to make the diagnosis.

Data from other studies and databases were analyzed by researchers to determine current rates of MS in 203 countries and then grouped into world regions and by income levels.

Prevalence of MS in high income countries was a mean 46 per 100,000 people vs 10 per 100,000 in low-income countries. The cost for health care per capita was $2,805 for high-income countries, compared to $45 in low-income countries.
 
Gross domestic product per capita, current health expenditure per capita, income levels, the availability of brain scans to diagnose MS, the number of neurologists per capita, and universal health care were examined for each location. Lifestyle factors, such as obesity and tobacco use, were also reviewed.

After adjustment for covariates, with every increase of 1 standard deviation in health expenditure per capita, MS prevalence increased by 0.49 and with every increase of 1 standard deviation in latitude, MS prevalence increased by 0.65.

However, the link between latitude and MS decreased by more than 20% when health care expenditure per capita was considered.

In high-income countries, rates of MS were linked with gross domestic product per capita, current health expenditure per capita, and the number of neurologists but not tobacco use and obesity or the number of MRI units per capita.

In low-income countries, there were no associations with any of these factors, which may be explained by a lack of significant variation in the data.

Study author Deanna Saylor, MD, MHS, of Johns Hopkins University School of Medicine in Baltimore and a member of the American Academy of Neurology finds with this data that greater investment in health care leads to more robust reporting of rates of MS, and said. 

 “Strategies are urgently needed to lessen the shortages in trained professionals and critical technology that prevent the accurate assessment of the burden of MS in low-income countries. The current lower reported rates of MS in these countries can obscure the need for training of medical providers about MS and limit investment into improving diagnosis and treatment in areas where scarce resources are often directed toward diseases that are believed to be the most common.”