Racial Composition, Socioeconomic Status and Shigellosis Among Children in Miami-Dade County

BACKGROUND:  There were 536 confirmed cases of shigellosis between January 1, 2014 and June 30, 2014 in Miami-Dade County, compared to a total of 85 and 107 confirmed cases in 2012 and 2013. Miami-Dade County differs from other counties in that 51.2% of its residents are foreign-born, a percentage greater than any other county in the United States. About 19.1% of its 2.5 million residents live below the poverty line. The study explores neighborhood socioeconomic disparities in shigellosis incidences among children ages 0-9 years in Miami-Dade County from January 2003 to June 2014.

METHODS: Shigellosis cases were obtained from Merlin, the Florida Department of Health Epidemiology Disease Reporting System, with symptom onset dates between January 2003 and June 2014, as of July 2, 2014. Countywide population by age and race/ethnicity was obtained from Florida Charts. Population demographics for each census tract, including age and race/ethnicity, poverty rates, community-wide level of education, and percentage of adults twenty-five years and older was obtained from the U.S. Census Bureau, 2008-2012 American Community Survey (12).   All data analyses were conducted using ArGIS and SAS 9.3. The multivariate Poisson regression analysis was used to estimate crude and adjusted relative risk (RR) with 95% Confidence Intervals (CI).

RESULTS:  Young children age 1-4 and 5-9 accounted for the majority of shigellosis cases reported, 36 % and 38.3% respectively. There was an increase in incidence rates as poverty level within a community increased. Neighborhoods  where more than 30% of adults had an education level under high school, had a higher incidence of shigellosis (58.7 cases per 100,000), compared to those whose adult population ranged from 20 to 30% (51.3 cases per 100,000) and communities where education was fewer than 20% (30.9 cases per 100,000). Poisson regression analysis showed that non-Hispanic blacks and Hispanic children were 9 and 6.2 times more likely to have shigellosis compared to non-Hispanic whites after adjusted poverty, adult education level, and children population.

CONCLUSIONS: Our results showed significant disparities between socioeconomic status and shigellosis incidence among children age 0 to 9 years in Miami-Dade County from January 2003 to June 2014. Public health related education in low socioeconomic areas may need to be improved.