A new review of hundreds of research articles has shown that the prevalence of multiple sclerosis (MS) is far higher than previously thought amongst the U.S. population.
The review of articles published between 1990 and 2005, has found that nearly 1 out of 1,000 people has multiple sclerosis (MS) which is 50 percent higher than a review done in 1982.
The authors from the National Institute of Neurological Disorders and Stroke, at the National Institutes of Health say it is unclear whether the figures represent an improvement in diagnosis or whether the incidence is in fact increasing.
They believe further study is warranted.
To estimate the current incidence and prevalence of 12 neurological disorders in the United States, Deborah Hirtz, lead author of the review and her colleagues reviewed studies from nearly 500 articles currently available.
This presented a wide range of estimates for some diseases; for some disorders the best available data was from western Europe, which was extrapolated to the U.S. population in order to get accurate estimates.
Dr. Hirtz is a program director for clinical trials at the Institute and a member of the American Academy of Neurology.
The researchers say the rate of Alzheimer's disease was up substantially from the past estimate and 67 out of every 1,000 elderly Americans are now affected by the disease while the prevalence of Parkinson disease remained at 9.5 per 1,000 people.
The researchers also found that 101 out of every 100,000 Americans experience a traumatic brain injury, a decrease which they say possibly reflects more restrictive hospital admission criteria and possibly improvements in motor vehicle safety.
The study found 183 out of every 100,000 people suffer a stroke each year, and one in 100 has had a stroke in the past, while nearly four out of every 100,000 Americans have ALS (Lou Gehrig's disease).
As many as 5 out of every 100,000 have a new onset spinal cord injury each year, while almost 6 out of every 1,000 children have autism and 2 out of every 1,000 children have cerebral palsy.
Dr. Hirtz says accurate estimates of the numbers of people affected by neurological disorders are needed to understand the burden these conditions place on patients, families, and society, in order to plan and carry out research on their causes and treatment, and to provide adequate services for sufferers.
The review is published in the January 30, 2007, issue of Neurology, the scientific journal of the American Academy of Neurology.