It's finally official: Nearly 900,000 Americans, and perhaps even more, suffer from multiple sclerosis (MS), double the 400,000 long-accepted figure.
Since MS News today First reported on this discovery in November 2017, the National Multiple Sclerosis Society (NMSS) study, which came to this conclusion, was the subject of a peer review process and has been accepted for publication in Neurology, the journal of the American Academy of Neurology (AAN).
It was published online on February 15 in the form of three articles:Validation of an MS case identification algorithm in administrative health claim datasets,""The prevalence of multiple sclerosis in the United States: a population-based estimate based on data on health claims,"and"A new way to estimate the prevalence of neurological diseases in the United States: illustrated by MS"The print edition will be published on March 5th.
The $ 1 million NMSS study – almost five years of preparation – followed complaints that scientists had grossly underestimated the number of people living with the disease.
"After spending a lot of time saying that the initial estimates were based on the best scientific data of the time, our supporters felt that we were not getting everyone," said Tim Coetzee, responsible advocacy, services and research at the NMSS. a telephone interview.
"This study and the resulting innovation gives us confidence that we now have a stronger representation of the number of people living with MS in the United States," said Coetzee. "This gives us the opportunity to engage with policy makers, legislators and businesses on the impact of MS on the population and to talk about the burden of disease."
Women now account for 74% of multiple sclerosis patients
Dr. Coetzee also stated that the unique approach developed by about fifteen researchers participating in the study could be applied to other neurological diseases lacking national registries, such as Parkinson's or Alzheimer's.
"It taught us that we could use existing data from public and private insurance companies to get a fairly modest estimate," he said. "The algorithms can be adapted. You would not need to modify it for this disease, but it can be done. "
The study is based on data from five national databases – Optum, Truven Health Market Scan, the Department of Veterans Affairs, Medicare and Medicaid – and a regional database, Kaiser Permanente. from Southern California. Together, these six databases provided information on more than one-third of the US population, explaining that "almost all people with MS, except uninsured people, would be captured in one of these programs.
"What this means is that we have to work harder because the need is greater than we had imagined," said Nick LaRocca, vice president of health care research. , benefits and policies of the NMSS, headquartered in Hackensack, New Jersey. . "For people with MS, that means we have more constituents and we have clarified something important about the nature of MS as a medical condition."
According to the study, which extrapolated data from 2010 to 2017, this electoral district had between 851,749 and 913,925 people. The study – which excludes children, prisoners and undocumented immigrants – does not distinguish between specific types of MS, such as relapsing remitting multiple sclerosis (RRMS) or primary progressive multiple sclerosis (PPMS). ).
But he draws notable conclusions. MS now affects 362 inhabitants per 100,000, compared to 309 per 100,000 in 2010, 85 per 100,000 in 1994 and 58 per 100,000 in 1976. And 74% of people with MS are women, compared with 63% in 1976.
"I do not know if this means that women are diagnosed faster than men," said LaRocca, who has been leading the MS Prevalence Initiative since its launch in 2014. "It may be that now let's count more precisely, we can get a better estimate. "
Geography is an important factor in the prevalence of MS
There is also a correlation with the prevalence of MS and distance from Ecuador. The inhabitants of the nine Northeastern American states – Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, and Vermont – had a prevalence of 377 per 100,000 population, while those in the South and West each had a prevalence rate of 277 per 100,000.
The NMSS study does not attempt to calculate the state-by-state prevalence of disease, although it cites a series of previous studies conducted between 1985 and 2011 that showed the lowest prevalence of MS in the country in a single country. 19 counties surrounding Lubbock, Texas (39.9 per 100,000) and highest prevalence of MS in Olmstead County, Minnesota (191.2 per 100,000).
Among all the age groups, sex and regions studied by the NMSS, the highest prevalence was observed among women aged 45 to 54 in the Northeast (762.3 per 100,000), while the lowest was among men aged 18 to 24 in the South (19.2%). per 100,000).
"There are many reasons for this geographical variation," LaRocca said. "One of the theories is that MS is linked to exposure to ultraviolet radiation, also known as sunlight, which, together with the human body, has the effect of producing vitamin D, which seems a little protective. Thus, people exposed to less sunlight, especially at the beginning of their lives, tend to be more exposed. "
In fact, Canada has always had the highest prevalence of multiple sclerosis in the world, with rates also high in Northern Europe – particularly in the Scandinavian countries – while the disease was almost unheard of in tropical regions of Africa and South America.
LaRocca said: "Migration studies have shown that people who have migrated from a high-risk area to an area of low risk very early on remain at risk for the area they come from. And Australian studies have shown that the variance of MS risk is not associated with vitamin D, but on something else. It is possible that ultraviolet rays have a direct impact on the immune system. "