Neighborhood socioeconomic position and tuberculosis transmission: a retrospective cohort study.
BACKGROUND
Current understanding of tuberculosis (TB) genotype clustering in the US is based on individual risk factors. This study sought to identify whether area-based socioeconomic status (SES) was associated with genotypic clustering among culture-confirmed TB cases.


METHODS
A retrospective cohort analysis was performed on data collected on persons with incident TB in King County, Washington, 2004-2008. Multilevel models were used to identify the relationship between area-level SES at the block group level and clustering utilizing a socioeconomic position index (SEP).


RESULTS
Of 519 patients with a known genotyping result and block group, 212 (41%) of isolates clustered genotypically. Analyses suggested an association between lower area-based SES and increased recent TB transmission, particularly among US-born populations. Models in which community characteristics were measured at the block group level demonstrated that lower area-based SEP was positively associated with genotypic clustering after controlling for individual covariates. However, the trend in higher clustering odds with lower SEP index quartile diminished when additional block-group covariates.


CONCLUSIONS
Results stress the need for TB control interventions that take area-based measures into account, with particular focus on poor neighborhoods. Interventions based on area-based characteristics, such as improving case finding strategies, utilizing location-based screening and addressing social inequalities, could reduce recent rates of transmission.
Division of Epidemiology & Biostatistics, University of Arizona, Tucson, AZ, USA. eoren@email.arizona.edu.
Eyal
E
Oren
Masahiro
M
Narita
Charles
C
Nolan
Jonathan
J
Mayer
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D055361:Multilevel Analysis; D012111:Residence Characteristics; D012189:Retrospective Studies; D012923:Social Class; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D014861:Washington / Q000453:epidemiology