Chlamydia is the most common nationally notifiable disease in the U.S.
and disproportionately affects young women. Chlamydial infections are asymptomatic
in most women16 and, if untreated, can result in serious complications,
including pelvic inflammatory disease (PID), infertility, and ectopic
pregnancy. A pregnant woman infected with chlamydia can transmit infection
to her child during delivery, potentially leading to neonatal pneumonia.
In addition, chlamydial infections have been shown to facilitate the
transmission of HIV. Despite these complications, chlamydia is easily treated
and cured
with antibiotics.
In 2000, for the first time, regulations in all 50 states
and DC required the reporting of chlamydia cases. Trends in chlamydia
case reporting from many states and areas are more reflective of changes
in testing,
diagnosis, and reporting of cases, rather than actual trends in disease
incidence. Because of this limitation, the CDC primarily monitors chlamydia
trends not by rates (number of positive cases/population), but by positivity
or estimated prevalence
(number of positive cases/number tested).12 Chlamydia positivity data
are not readily available for any of the IHS Areas; therefore, only
chlamydia rates are shown in this report.
In 2004, 929,462 chlamydial
infections were
reported in the U.S. This case count corresponds to a rate of 319.6
cases per 100,000 population, a 5.9% increase from 2003 (301.7 cases
per 100,000
population).
Key Points and Trends
In 2004, among all race/ethnicities, AI/AN had the second highest chlamydia
rate (705.8 cases per 100,000 population), which was 4.9 times higher than
the rate for whites (143.6 cases per 100,000 population). African-Americans
had the highest chlamydia rate (1,209.4 cases per 100,000 population).
In 2004, 16,741 of 929,462 chlamydial infections (1.8%) occurred among AI/AN.
The AI/AN chlamydia rate increased by 5% during 2003-2004 (2003 rate: 672.2
cases per 100,000 population).
In 2004, the chlamydia rate among AI/AN women in the U.S. (1,127.8 cases
per 100,000 females) was over 4 times higher than the rate among AI/AN men
(270.9 cases per 100,000 males), likely reflecting a greater number of women
screened for this infection. This rate ratio was similar for rates by sex
in the total U.S. (485.0 cases per 100,000 females and 147.1 cases per 100,000
males).
Among AI/AN women, the highest age-specific rates of reported chlamydia
in 2004 were among 20- to 24-year-olds (4,672.4 per 100,000 females) and 15-
to 19-year-olds (4,358.2 per 100,000 females). These two age groups also represented
the highest age-specific rates among all women in the U.S. (15-19 years: 2,761.5
per 100,000 females and 20-24 years: 2,630.7 per 100,000 females).
Age-specific rates among AI/AN men, while substantially lower than the rates
in AI/AN women, were highest among 20- to 24-year-olds (1,144.6 cases per
100,000 males). This age group also had the highest rates among all men in
the U.S. (744.7 cases per 100,000 males).
