Sociodemographic and Spatial-Temporal Cluster Analyses of Socioeconomic Status and Salmonellosis in Georgia, 2010-2012 Open Access

Harney, Shannon (2014)

Permanent URL: https://etd.library.emory.edu/concern/etds/tb09j6496?locale=en
Published

Abstract

Background

The purpose of this study was to investigate the association between socioeconomic status and salmonellosis outcomes in Georgia from 2010 to 2012 using sociodemographic groups and spatial-temporal analyses.

Methods

Poisson regression models were utilized to estimate the incidence, hospitalization, and case fatality rate ratios for all non-typhoidal serotypes of Salmonella enterica, and Salmonella Enteritidis, Typhimurium, Newport, and Javiana. The highest socioeconomic status group (A of A-D) or subgroup (A.1 of A.1-D.7) served as the reference category. Spatial-temporal analyses were conducted to describe the geospatial distribution of Salmonella Newport and Javiana cases.

Results

7,590 cases of salmonellosis were included in the analysis. The incidence rate ratios were generally protective for Salmonella Enteritidis. The highest, significant incidence rate ratios occurred in sociodemographic group C and D for Salmonella Typhimurium (IRR 1.82-2.36), A and C for Salmonella Newport (1.90-2.60), and C for Salmonella Javiana (IRR 1.59-1.79). Significant hospitalization rate ratios above the null were noted among many of the subgroups in A, C, and D for Salmonella Typhimurium, Newport, and Javiana; hospitalization rates were similar to the null for Salmonella Enteritidis. The case fatality rate ratio was significantly greater than the null for group C (RR=2.89, p=0.01). The spatial-temporal analyses identified geospatial clusters in the lower two-thirds and northeastern corner of the state for both Salmonella Newport and Javiana.

Discussion

These results suggest an increased incidence, hospitalization, and case fatality rate for salmonellosis cases in the lower middle socioeconomic status group (C) relative to those in the highest socioeconomic status group (A). The spatial-temporal analyses further identified geospatial clusters in regions of the state mostly populated by cases in group C.

Table of Contents

I.

Background/Literature Review

1

A.

Burden of Salmonellosis

1

1.

National burden of Salmonella enterica

1

2.

Burden of Salmonella enterica in Georgia

2

3.

Patterns of illness by serotype

3

4.

Surveillance and diagnostics

4

B.

Epidemiology of Salmonella enterica

4

1.

Organism and nomenclature

4

2.

Reservoirs and environmental viability

5

C.

Salmonellosis and Socioeconomic Status

6

1.

Association between socioeconomic variables and salmonellosis

6

2.

Hypotheses for the association between higher socioeconomic status and higher incidence

7

II.

Manuscript

9

A.

Abstract

9

B.

Introduction

11

C.

Methods

13

1.

Study population

13

2.

Sociodemographic groups

14

3.

Serotypes

14

4.

Analysis

15

D.

Results

18

1.

Characteristics of the study population

18

2.

Rate ratios for incidence by serotype and group

19

3.

Rate ratios for hospitalization by serotype and group

21

4.

Rate ratios for case fatality by serotype and group

22

5.

Spatial-temporal analyses of Salmonella Newport and

Javiana cases

22

E.

Discussion

24

1.

Incidence, serotype, and sociodemographic group

24

2.

Hospitalization, case fatality, serotype, and group

25

3.

Spatial-temporal analyses

25

4.

Limitations

26

F.

References

27

G.

Tables

30

H.

Figures

38

III.

Summary, Public Health Implications, Possible Future Directions

53

IV.

Appendices

56

A.

Description of the Sociodemographic Groups and Subgroups

56

B.

Model Selection Tables

58

C.

Comparison of the Year of Onset, Outcomes, and Serotypes

for Included and Excluded Cases

59

D.

Emory University IRB Approval Letter

60

E.

Georgia Department of Public Health IRB Approval Letter

62

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