Knock‐Knock: A Population‐Based Survey of Risk Behavior, Health Care Access, andChlamydia trachomatisInfection among Low‐Income Women in the San Francisco Bay Area

To estimate the prevalence of urogenital chlamydial infection among young, low-income women in northern California and to describe correlates of infection, a population-based door-to-door household cluster survey was conducted from 1996 through 1998. The participants included 1439 women 18-29 years of age, with a mean age of 24 years, most of whom were African American (43%) or Latina (23%) and had a median income of $500-$999 per month. Most (94%) had received health care in the past year, and approximately 50% was covered by state insurance programs. Although more than half (62%) had had a recent pelvic examination, only 42% had recently used a condom with a new partner. The prevalence of urogenital chlamydial infection was 3.2% (95% confidence interval, 2.2%-4.2%). Women with chlamydia were more likely to be younger (18-21 years of age) and nonwhite and to have lower socioeconomic status. These data demonstrated an approximately 2-3-fold greater burden of infection than routine surveillance data have suggested.