Area-Level Community Factors Associated with Chlamydia and Gonorrhea Among Female Adolescents, San Francisco, 2010

Background: Adolescents bear a disproportionate burden of STDs in San Francisco.  The role of community-level factors that modify this risk is poorly understood.

Objectives: We conducted an area-level ecological analysis by census tract exploring which social determinants were associated with female adolescent chlamydia and gonorrhea rates in San Francisco in 2010.

Methods: Chlamydia and gonorrhea cases reported to the San Francisco Department of Public Health in 2010 were geocoded to census tract, and tract-specific morbidity rates were calculated.  American Community Survey 2005-2009 estimates provided the following tract-specific proportions of households/populations that were: female-headed, vacant, renter-occupied, spending >=30% income on rent, occupied by >1 person per room, receiving public assistance, receiving food stamps, African-American, unemployed, did not complete high school, and below poverty level.  Incarceration estimates, homicides, and graffiti complaints from 2010 were also geocoded.  Multivariable linear regression models explored associations between these community-level factors and STD rates among female adolescents.

Results: Among females under age 25 in San Francisco in 2010, 1,085 chlamydia and 143 gonorrhea cases were geocoded to 176 census tracts.  The tract-specific rate of chlamydia was positively associated with incarceration (p<0.0005), proportion of population that is African-American (p=0.001), proportion of households receiving food stamps (p=0.035), and inversely associated with proportions of population below poverty level (p=0.005) and vacant households (p<0.0005).  Gonorrhea rates were positively associated with incarceration (p<0.0005), proportions unemployed (p=0.009) and receiving food stamps (p<0.0005), and inversely associated with proportions of population below poverty level (p=0.039), less than high school education (p=0.030), vacant households (p=0.013), and female-headed households (p=0.015).

Conclusions: This ecologic analysis suggests an important role of area-level factors.  Further study of the relationship between individual and community-level factors of STDs is warranted.

Implications for Programs, Policy, and Research: Individual-level risk factors alone may not explain the excess risk of STDs that adolescents bear.