Defense Date


Document Type


Degree Name

Doctor of Philosophy



First Advisor

Kate Lapane

Second Advisor

Derek Chapman

Third Advisor

May Kennedy

Fourth Advisor

Hongjie Liu


Abstract 1: A multi-level assessment of disproportionate population sex ratios and high-risk sexual behaviors among STD clinic patients Low male-to-female sex ratios in a population may influence high-risk sexual behaviors, such as multiple sex partners and inconsistent condom use, which facilitate the transmission of STDs. This study used multi-level modeling to assess whether population sex ratios were associated with these two individual-level behaviors. All analyses were stratified by gender. Interview data were collected from patients (N = 9,203, 48% male) attending participating STD clinics. Interviews included information on socio-demographics and sexual behavior, including number of sex partners in the previous 3 months and condom use at last sex. The sex ratio per census tract was obtained from the U.S. Census Bureau. There was no association between sex ratio and multiple sex partners or condom use for either men or women. That is, we found no evidence that a shortage of men in census tracts was associated with increased engagement in high-risk sexual behavior.   Abstract 2: A multi-level assessment of neighborhood vacancy rates and high-risk sexual behaviors among STD clinic patients The “broken windows” theory posits that physical neighborhood deterioration, and its association with reduced social cohesion, can lead to changes in individual behaviors. Thus individuals living in neighborhoods with high levels of deterioration may be more likely to engage in high-risk sexual behaviors. This study used multi-level modeling to evaluate the extent to which high residential vacancy rates increased the likelihood of individuals having multiple sex partners. Interview data, including data on patient demographics and sexual behaviors, were collected from patients (N = 6,347, 52% male) attending participating STD clinics in the Richmond, Virginia area from 2008-2010. Neighborhood vacancy rates were obtained from the U.S. Census Bureau. Fifty-one percent of men and 36% of women reported having 2 or more sex partners in the previous 3 months. Men who lived in census tracts with high vacancy rates were slightly more likely to report multiple sex partners (53.9%) compared to men who lived in low vacancy tracts (49.7%). In multi-level models, there was no association between high vacancy rates and having multiple sex partners among either women (OR = 0.98; 95% CI: 0.79, 1.20) or men (1.18; 95% CI: 0.99, 1.42). That is, we found no evidence that increased neighborhood deterioration, as measured by high residential vacancy rates, was associated with increased risk of having multiple sex partners among STD clinic patients.   Abstract 3: Residential segregation and gonorrhea rates in U.S. metropolitan statistical areas The residential segregation of black populations, often in areas of high economic disadvantage and low social status, may play a crucial role in the observed racial inequities in STD rates. An ecological analysis of 2005-2009 average gonorrhea rates was performed across 277 U.S. metropolitan statistical areas (MSAs). The black isolation index and Gini index of income inequality were used as proxy measures for racial and economic residential segregation respectively, derived from 2005-2009 U.S. Census estimates. We used logistic regression modeling to produce estimates of odds ratios (OR) and 95% confidence intervals (CI) for the association between a high black isolation index and Gini index, both independently and in combination, on gonorrhea rates in MSAs. Effect measure modification was assessed by calculating the relative excess risk due to interaction (RERI) between the two indices. Compared to MSAs with low levels of racial segregation, MSAs with high levels of racial segregation had increased odds of high gonorrhea rates (adjusted OR 5.54; 95% CI: 2.29-13.44). Adjustment for potential confounders did not noticeably impact the relationship between the Gini index and gonorrhea, with higher levels of income inequality predicting higher gonorrhea rates (adjusted OR = 2.47; 95% CI: 1.21-5.03). In combined models, the influence of racial residential segregation on gonorrhea rates was stronger than that of income inequality-based segregation; there was no evidence of additivity or a multiplicative interaction. Residential segregation by race or income equality may be a key component in the perpetuation of high rates of gonorrhea and other STDs among black populations in the U.S.


© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

May 2012

Included in

Epidemiology Commons