Sociodemographic factors and the variation in syphilis rates among US counties, 1984 through 1993: an ecological analysis.
OBJECTIVE
Syphilis in the United States is focally distributed, with high incidence rates in the South and in metropolitan areas nationwide. In this study an ecological analysis, using the county as the unit of analysis, was performed to generate hypotheses about community-level determinants of syphilis rates.


METHODS
Bivariate rank correlations and multivariate, backward stepwise elimination linear regressions were performed. Mean annual incidence of primary- and secondary-stage syphilis in a county was the dependent variable, and county sociodemographic characteristics (from census data) were the independent variables.


RESULTS
In the multivariate regression model, sociodemographic characteristics accounted for 71% of the variation in syphilis rates among counties. With other factors accounted for, the most highly correlated characteristics were percentage non-Hispanic Black population, county location in the South, percentage of the population that was urban, percentage Hispanic population, and percentage of births to women younger than 20 years.


CONCLUSIONS
Most of the variation in syphilis rates among counties is accounted for by sociodemographic characteristics. Identification and remediation of modifiable health determinants for which these factors are markers are needed to improve the health status of these populations.
Kilmarx
P H
PH
Division of STD Prevention, Centers for Disease Control and Prevention (CDC), Atlanta, Ga., USA.
Zaidi
A A
AA
Thomas
J C
JC
Nakashima
A K
AK
St Louis
M E
ME
Flock
M L
ML
Peterman
T A
TA
D000293:Adolescent; D000328:Adult; D004463:Ecology; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D015994:Incidence; D016014:Linear Models; D008297:Male; D015999:Multivariate Analysis; D011159:Population Surveillance; D011203:Poverty; D044469:Racial Groups; D012111:Residence Characteristics; D012959:Socioeconomic Factors; D013587:Syphilis / Q000453:epidemiology* / Q000209:etiology; D014481:United States / Q000453:epidemiology