Disparities of Shigellosis Rates Among California Children by Census Tract Poverty Level and by Race/Ethnicity,

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1 Disparities of Shigellosis Rates Among California Children by Census Tract Poverty Level and by Race/Ethnicity, Rebecca Cohen, MPH CSTE/CDC Applied Epidemiology Fellow California Department of Public Health Division of Environmental and Occupational Disease Control

2 Introduction Widespread agreement about toll of poverty on health Absence of socioeconomic data collection in most public health surveillance systems Socioeconomic health disparities are invisible without socioeconomic data No ability to assess differences over time, space, group, or across outcomes

3 Introduction Harvard Public Health Disparities Geocoding Project methodology Detailed method on Harvard website: Geocode cases Link to census tract data Analyze cases for socioeconomic disparities by demographics Method used on some chronic diseases by some states; use on infectious diseases uncommon

4 Aims of this study To use the Harvard Public Health Disparities Geocoding Project methodology to Determine whether socioeconomic disparities exist in shigellosis rates among children in California Analyze the contribution of socioeconomic inequalities to racial/ethnic disparities in shigellosis

5 Shigellosis in US Common enteric bacterial disease diarrhea, fever, and stomach cramps Reportable in U.S. Incidence highest among children Shigella sonnei ~70%, Shigella flexneri ~25% In US each year: 14,000 cases reported 131,254 estimated cases; 1,456 hospitalizations; 10 deaths Risk groups/settings Children in child care centers International travels MSM

6 Reletive rate (log scale) Shigellosis in US Relative rates of laboratory-confirmed infections with Shigella, Yersinia, and Cryptosporidium compared with rates, by year, FoodNet * Shigella Yersinia Cryptosporidium *The position of each line indicates the relative change in the incidence of that pathogen compared with The actual incidences of these infections cannot be determined from this graph. Data for 2012 are preliminary.

7 Number of cases Rate per 100,000 Shigellosis in California Cases Rate * Estimated year of onset 0 Source: Epidemiologic Summary of Shigellosis in California, ,

8 < Rate per 100,000 Shigellosis in California * 0 Age in years Source: Epidemiologic Summary of Shigellosis in California, ,

9 Percent Shigellosis in California White, non-hispanic Asian, Pacific Islander Native American Shigellosis cases** Hispanic Black, non-hispanic Other or multi-race*** California population Source: Epidemiologic Summary of Shigellosis in California, ,

10 Objectives Use reported cases of shigellosis in California data Children 0-14 years old Analyze by Age group Race/ethnicity % population below federal poverty level

11 Methods Geocode cases to census tract (CT) Download 2010 CT information Merge numerator and denominator data Calculate incidence rates by census tract poverty level

12 Methods Population attributable fraction PAF agg = iexcess number of cases i number of cases = inumber of cases PAF i i number of cases Poisson Regression Log(cases) = intercept + age + race + poverty + log (population) 0 4 yrs White 5% 5 9 Asian 5 9% Black 10 19% Hispanic 20 29% 30 39% 40%

13 Results 20,949 cases reported to CDPH, ,740 children under 14 9,178 geocoded Total 9,178 Sex Male 49% Age Category Under 5 50% % % Race/Ethnicity Hispanic 70% Non-Hispanic white 8% Black 4% Asian, Pacific Islander 3% Other 1% Missing 16% Year of Report % % % %

14 Cases per 100,000 Results Shigellosis Incidence (per 100,000 population) in California Under Age Category (years) 5.5

15 Cases per 100,000 Results Shigellosis Incidence (per 100,000 population) in California Asian White Black Hispanic Race/Ethnicity 5.5

16 Cases per 100,000 Results 25 Age-Adjusted Shigellosis Incidence Rates, California, % 5.0% - 9.9% 10.0% % 20.0% % 30.0% % 40% or more Percent of population below federal poverty level

17 Results Census Tract Poverty Incidence Rate per 100,000 Incidence Rate Difference 95% confidence interval Incidence Rate Ratio 95% confidence interval 0-4.9% 4.08 Ref -- Ref % - 9.9% % % % % % % % or more

18 Results PAF = iexcess number of cases i number of cases = 0.62 Preventable cases = 9, = 5,691

19 Cases per 100,000 Results Asian White Black Hispanic Less than 5.0% 5.0% - 9.9% 10.0% % 20.0% % 30.0% % 40% or more 5 0 Under Under Under Under Asian Asian Asian Black Black Black White White White Hisp Hisp Hisp

20 Results Unadjusted RR Poisson RR (95% CL) Poverty 5% below poverty level 1.0 (ref) 1.0 (ref) 5-9% (1.4, 1.8) 10-19% (2.0, 2.4) 20-29% (2.6, 3.3) 30-39% (3.0, 3.7) 40% (3.6, 4.6) Race White 1.0 (ref) 1.0 (ref) Asian (0.6, 0.9) Black (1.4, 1.9) Hispanic (3.0, 3.6) Age 5 years (3.3, 3.8) (2.5, 2.9) (ref) 1.0 (ref)

21 Conclusions In California, rates of shigellosis in children increase with CT poverty and were highest for those in the poorest census tracts Rates were higher for Hispanic children in general, but some of the poorest White and Black children still have higher rates than all children in lower poverty categories Differences by CT poverty smaller, but still apparent, after adjusting for race Our analysis shows that socioeconomic disparities strongly affected shigellosis rates among California children across all racial/ethnic groups

22 Discussion Probably first study in US examining disparities in shigellosis rates in children by race/ethnicity and by poverty level High percentage of cases geocoded Feasible to geocode addresses of surveillance data as a way to assign socioeconomic status to cases Future analysis will examine household crowding In California, Shigella prevention messages should target all poor families with children and Hispanic families with children

23 Acknowledgements California Department of Public Health Dan Smith Duc Vugia Debra Gilliss Farzaneh Tabnak Council of State and Territorial Epidemiologists

24 Questions?

25 Methods Fay and Feuer ɣ confidence interval Notation Variance Upper and Lower Limit

26 Incidence (per 100,000 population) Results Disparities in Shigellosis Rates: Comparing the burden of shigellosis by Census Tract resources and Race Asian Black White Hispanic Race/Ethnicity Percent of population below poverty line 0-4.9% 5-9.9% % % % 40%