Incidence of Multiple Sclerosis in Puerto Rico, 2014: A Population-Based Study

Background: Multiple sclerosis (MS) affects millions of people worldwide. The estimates for MS incidence are difficult to obtain but are important for understanding MS etiology, developing prevention strategies, and service planning. This study is aimed at estimating the 2014 incidence of MS in Puerto Rico (PR). Methods: The PR MS Foundation's registry was used as the data source. Neurologists, specialty pharmacies, MRI centers, health insurance companies, and the PR Department of Health identified MS cases missed by the registry. MS patients were 18 years and older and met the 2010 revised McDonald criteria. Age-standardized MS incidence rates and their corresponding 95% CIs were computed. Results: A total of 144 new MS cases were diagnosed in 2014. The age-standardized MS incidence rate was 5.1/100,000 (95% CI 4.3-5.9). The incidence rate was 7.1/100,000 (95% CI 5.7-8.5) for females and 2.9/100,000 (95% CI 2.0-3.8) for males. MS cases were mostly females (72.9%) with a mean age of 41.0 years (±1.0). Conclusion: According to the country estimates, PR has a higher MS incidence than other Caribbean and Latin American countries, but a lower incidence compared to countries at higher latitudes. Our findings provide insights into the MS etiology in the Hispanic population that require additional research.