Table 1.
Seroprevalence of Chlamydia trachomatis Overall and Stratified by Individual-Level Characteristics in US Females Ages 18-39, as Measured by 4 Definitions of Seropositivitya
| ELISA | MBA | Both | Either | |
|---|---|---|---|---|
| Characteristics | Weighted % (95% CI) | Weighted % (95% CI) | Weighted % (95% CI) | Weighted % (95% CI) |
| Overall | 30.0 (25.5–35.0) | 29.4 (25.8–33.0) | 23.0 (19.7–27.0) | 36.3 (32.0–41.0) |
| Age, y | ||||
| 18–24 | 27.4 (22.4–32.9) | 27.9 (22.9–33.2) | 21.7 (17.8–25.9) | 33.6 (27.8–39.8) |
| 25–29 | 29.3 (23.3–35.8) | 27.4 (22.6–32.6) | 22.1 (17.3–27.4) | 34.6 (28.8–40.8) |
| 30–34 | 31.5 (24.6–39.1) | 30.4 (23.9–37.5) | 21.3 (16.0–27.4) | 40.6 (34.4–46.9) |
| 35–39 | 32.3 (25.3–40.0) | 32.4 (25.2–40.3) | 27.5 (21.2–34.5) | 37.3 (29.1–45.9) |
| Race/ethnicity | ||||
| Non-Hispanic White | 23.0 (18.1–28.5) | 21.4 (17.5–25.7) | 14.8 (11.6–18.5) | 29.6 (24.9–34.6) |
| Non-Hispanic Black | 60.5 (54.4–66.5) | 68.0 (61.1–74.5) | 59.7 (53.5–65.8) | 68.8 (61.9–75.2) |
| Mexican American | 31.8 (25.9–38.2) | 30.9 (26.1–36.0) | 25.4 (20.6–30.7) | 37.4 (31.5–43.5) |
| Other Hispanic | 35.1 (27.8–42.9) | 35.0 (28.1–42.4) | 28.7 (21.8–36.6) | 41.3 (34.7–48.2) |
| Non-Hispanic Asian | 17.0 (11.0–24.4) | 15.5 (10.3–22.1) | 9.9 (5.6–15.8) | 22.6 (16.1–30.2) |
| Other race, including multiracial | 43.0 (23.2–64.5)a | 35.9 (22.5–51.2) | 33.4 (21.2–47.6) | 45.5 (24.2–68.1)a |
| Born in the 50 US states | ||||
| No | 30.3 (25.3–35.7) | 29.8 (25.5–34.5) | 23.5 (19.7–27.6) | 36.7 (31.6–42.0) |
| Yes | 28.5 (23.0–34.4) | 27.4 (23.4–31.7) | 21.0 (16.7–26.0) | 34.8 (29.7–40.2) |
| Poverty status | ||||
| Below the poverty level | 39.2 (33.0–45.6) | 42.4 (35.8–49.2) | 35.1 (29.6–41.0) | 46.4 (39.5–53.4) |
| At or above poverty level | 26.3 (21.7–31.4) | 25.0 (21.0–29.3) | 19.0 (15.6–22.7) | 32.4 (27.8–37.2) |
| Education | ||||
| Less than high school | 36.8 (30.2–43.8) | 41.6 (34.7–48.7) | 32.2 (26.0–38.9) | 46.2 (38.9–53.6) |
| GED/high school degree/some college | 34.0 (27.2–41.2) | 34.5 (27.5–42.1) | 28.2 (21.9–35.2) | 40.3 (33.2–47.8) |
| College degree of higher | 27.4 (22.6–32.5) | 25.4 (22.0–29.0) | 19.6 (16.7–22.8) | 33.1 (28.5–38.1) |
| Marital status | ||||
| Never married | 34.7 (29.5–40.3) | 33.9 (29.1–38.8) | 29.2 (25.1–33.6) | 39.4 (33.7–45.3) |
| Married/living with partner | 25.8 (21.3–30.6) | 26.2 (21.7–31.1) | 18.6 (15.0–22.7) | 33.3 (28.7–38.1) |
| Widowed/divorced/separated | 48.6 (35.2–62.2) | 45.7 (35.5–56.1) | 38.2 (28.6–48.6) | 56.1 (42.9–68.6) |
| Not askedb | 23.4 (15.9–32.4) | 18.9 (12.4–26.8) | 15.3 (10.7–20.8) | 27.0 (18.5–37.0) |
| Lifetime sexual partners | ||||
| 0–1 | 11.2 (7.0–16.8) | 7.4 (4.9–10.7) | 4.8 (3.0–7.1) | 13.9 (9.1–20.0) |
| 2–3 | 23.9 (17.3–31.4) | 18.6 (13.4–24.9) | 14.3 (10.3–19.1) | 28.2 (21.0–36.4) |
| 4–7 | 37.1 (30.4–44.3) | 40.7 (33.7–48.0) | 33.1 (27.3–39.4) | 44.7 (37.0–52.6) |
| 8–15 | 37.4 (28.8–46.7) | 38.5 (31.7–45.8) | 29.8 (23.0–37.3) | 46.2 (37.8–54.7) |
| > 15 | 43.2 (31.0–56.0) | 47.2 (36.9–57.6) | 38 (27.9–48.9) | 52.3 (40.3–64.2) |
| Sexual partner over past 12 mo | ||||
| 0 | 18.6 (10.0–30.3) | 14.5 (8.8–21.9) | 9.6 (4.9–16.3) | 23.5 (14.3–34.9) |
| 1 | 28.1 (23.8–32.8) | 27.8 (23.9–32.0) | 22.1 (18.8–25.7) | 33.8 (29.2–38.8) |
| 2 | 38.7 (30.4–47.5) | 40.2 (34.0–46.7) | 31.4 (25.0–38.3) | 47.5 (39.9–55.2) |
| New sexual partner over past 12 mo | ||||
| No | 28.1 (23.6 – 33.0) | 27.7 (23.8–31.8) | 21.9 (18.6–25.4) | 33.9 (29.0–39.0) |
| Yes | 34.9 (27.4 – 43.0) | 34.9 (28.5–41.7) | 26.8 (20.8–33.6) | 43.0 (36.0–50.2) |
| Age of sexual debut, yc | ||||
| ≤16 | 42.1 (36.9–47.4) | 43.4 (38.7–48.2) | 35.5 (31.6–39.6) | 49.9 (44.1–55.7) |
| 17–18 | 24.8 (17.6–33.3) | 26.5 (21.7–31.8) | 19.0 (14.2–24.6) | 32.4 (25.3–40.1) |
| ≥19 | 13.6 (9.1–19.2) | 10.2 (6.3–15.3) | 7.3 (4.7–10.6) | 16.5 (12.0–22.0) |
All data are weighted using pooled Medical Examination Center (MEC) survey weights provided by the National Center for Health Statistics.
Abbreviations: CI, confidence interval; ELISA, enzyme-linked immunosorbent assay; IgG, immunoglobin G; MBA, multiplex bead format assay; US, United States.
aDefinitions of positivity: ELISA, positive on the anti-pgp3 ELISA; MBA, positive on the anti-pgp3 MBA; both, positive on both an anti-pgp3 MBA and ELISA; either, positive on either the anti-pgp3 MBA and ELISA.
bNot asked of participants ages 18 to 19 years.
cOnly among those sexually experienced.