This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
Abstract
Objective: To determine whether the incidence of multiple sclerosis (MS) varies by race/ethnicity in a multiethnic, population-based cohort.
Methods: We conducted a retrospective cohort study of more than 9 million person-years of observation from the multiethnic, community-dwelling members of Kaiser Permanente Southern California health plan from January 1, 2008 to December 31, 2010. Incidence of MS and risk ratios comparing incidence rates between racial/ethnic groups were calculated using Poisson regression.
Results: We identified 496 patients newly diagnosed with MS who met McDonald criteria. The average age at diagnosis was 41.6 years (range 8.6–78.3 years) and 70.2% were women. The female preponderance was more pronounced among black (79.3%) than white, Hispanic, and Asian individuals with MS (67.8%, 68.1%, and 69.2%, respectively; p = 0.03). The incidence of MS was higher in blacks (10.2, 95% confidence interval [CI] 8.4–12.4; p < 0.0001) and lower in Hispanics (2.9, 95% CI 2.4–3.5; p < 0.0001) and Asians (1.4, 95% CI 0.7–2.4; p < 0.0001) than whites (6.9, 95% CI 6.1–7.8). Black women had a higher risk of MS (risk ratio 1.59, 95% CI 1.27–1.99; p = 0.0005) whereas black men had a similar risk of MS (risk ratio 1.04, 95% CI = 0.67–1.57) compared with whites.
Conclusions: Our findings do not support the widely accepted assertion that blacks have a lower risk of MS than whites. A possible explanation for our findings is that people with darker skin tones have lower vitamin D levels and thereby an increased risk of MS, but this would not explain why Hispanics and Asians have a lower risk of MS than whites or why the higher risk of MS among blacks was found only among women.
GLOSSARY
- CI=
- confidence interval;
- CIS=
- clinically isolated syndrome;
- ICD-9=
- International Classification of Diseases, ninth revision;
- MS=
- multiple sclerosis
Footnotes
Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Supplemental data at www.neurology.org
- Received September 19, 2012.
- Accepted in final form January 24, 2013.
- © 2013 American Academy of Neurology
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
Disputes & Debates: Rapid online correspondence
NOTE: All authors' disclosures must be entered and current in our database before comments can be posted. Enter and update disclosures at http://submit.neurology.org. Exception: replies to comments concerning an article you originally authored do not require updated disclosures.
- Stay timely. Submit only on articles published within the last 8 weeks.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- 200 words maximum.
- 5 references maximum. Reference 1 must be the article on which you are commenting.
- 5 authors maximum. Exception: replies can include all original authors of the article.
- Submitted comments are subject to editing and editor review prior to posting.