Gender-based Screening for Chlamydial Infection and Divergent Infection Trends in Men and Women

Current U.S. public health policies recommend routine chlamydial screening among women but not men. While data are available on trends in diagnosed infections reported to local health departments, comparable data are not available on trends in undiagnosed infections prevalent in the population. We compare undiagnosed infections in Baltimore, MD using population surveys of probability samples of Baltimore adults aged 18 to 35 years conducted in 1997-1998 and 2006-2009. Annual surveillance counts of infections diagnosed and reported to the Baltimore City Health Department are tabulated by sex and race.

Among men undiagnosed chlamydial infection increased from 1.6% to 4.0% between 1997-98 and 2006-09 (p=0.05) whereas prevalence among women declined from 4.3% to 3.1% (p=0.41; p=0.028 for test of interaction). The annual (average) number of diagnosed infections was substantially higher among women than men in both time periods and increased among men (391 in 1997-98 and 878 in 2006-09) and women (3255 in 1998 and 4475 in 2006-09). In both survey periods, undiagnosed infection was substantially higher among black than non-black adults (4.0% vs 1.2%, p=0.042 in 1997-98 and 5.5% vs 0.7%, p<0.001 in 2006-09).

Divergent trends in chlamydial infection by sex parallel the divergence in current screening policies