Table 1.
Incidence of T1D in NHW youth <20 years of age at diagnosis by year, age category, and sex and mean age at diagnosis, overall, and by sex: the SEARCH for Diabetes in Youth Study, 2002–2009
| 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | |
|---|---|---|---|---|---|---|---|---|
| All youth | ||||||||
| n | 712 | 681 | 672 | 710 | 727 | 768 | 792 | 782 |
| Population (denominator) | 2,917,577 | 2,892,275 | 2,864,217 | 2,853,332 | 2,855,636 | 2,847,022 | 2,849,514 | 2,847,765 |
| Age at diagnosis (years) | 9.68 (4.58) | 9.44 (4.62) | 9.83 (4.54) | 9.90 (4.45) | 9.95 (4.67) | 9.99 (4.33) | 9.80 (4.50) | 9.88 (4.42) |
| Incidence by age category* | ||||||||
| 0–4 years | 20.2 (17.1–23.9) | 22.5 (19.2–26.4) | 18.5 (15.5–22.1) | 17.6 (14.7–21.1) | 20.1 (17.0–23.8) | 16.9 (14.0–20.3) | 19.8 (16.7–23.5) | 18.5 (15.5–22.0) |
| 5–9 years | 31.5 (27.6–35.9) | 27.5 (23.8–31.7) | 31.3 (27.4–35.8) | 33.2 (29.1–37.8) | 31.7 (27.7–36.2) | 37.8 (33.5–42.8) | 37.9 (33.5–42.7) | 38.7 (34.3–43.6) |
| 10–14 years | 31.5 (27.8–35.7) | 33.4 (29.5–37.7) | 31.7 (28.0–36.0) | 37.8 (33.6–42.5) | 35.6 (31.6–40.2) | 39.7 (35.4–44.5) | 39.9 (35.5–44.8) | 38.5 (34.2–43.3) |
| 15–19 years | 14.2 (11.8–17.2) | 10.9 (8.8–13.5) | 12.5 (10.2–15.3) | 11.2 (9.1–13.8) | 14.8 (12.3–17.7) | 14.1 (11.7–17.0) | 14.4 (12.0–17.4) | 14.8 (12.3–17.8) |
| Total | 24.4 (22.7–26.3) | 23.5 (21.8–25.4) | 23.5 (21.7–25.3) | 24.9 (23.1–26.8) | 25.4 (23.7–27.4) | 27.0 (25.1–28.9) | 27.8 (25.9–29.8) | 27.5 (25.6–29.4) |
| Total, age-adjusted | 24.4 (23.9–24.8) | 23.5 (23.1–23.9) | 23.4 (23.0–23.8) | 24.8 (24.4–25.3) | 25.4 (24.9–25.8) | 26.9 (26.4–27.4) | 27.7 (27.2–28.2) | 27.4 (26.9–27.9) |
| Total, sex-adjusted | 24.4 (24.0–24.8) | 23.5 (23.1–24.0) | 23.5 (23.0–23.9) | 24.9 (24.4–25.3) | 25.4 (25.0–25.9) | 27.0 (26.5–27.4) | 27.8 (27.3–28.3) | 27.5 (27.0–27.9) |
| Total, age- and sex-adjusted | 24.4 (23.9–24.8) | 23.5 (23.1–23.9) | 23.4 (23.0–23.8) | 24.8 (24.4–25.3) | 25.4 (25.0–25.9) | 26.9 (26.4–27.4) | 27.7 (27.3–28.2) | 27.4 (26.9–27.9) |
| Females | ||||||||
| n | 324 | 336 | 324 | 307 | 322 | 362 | 365 | 370 |
| Age at diagnosis (years) | 9.19 (4.62) | 8.95 (4.41) | 9.72 (4.18) | 9.48 (4.30) | 9.60 (4.57) | 9.58 (4.30) | 9.45 (4.39) | 9.69 (4.12) |
| Incidence by age category | ||||||||
| 0–4 years | 22.1 (17.6–27.8) | 23.6 (18.9–29.5) | 17.2 (13.3–22.4) | 16.8 (12.9–21.9) | 21.0 (16.6–26.6) | 17.4 (13.4–22.6) | 17.7 (13.7–22.9) | 15.8 (12–20.7) |
| 5–9 years | 30.9 (25.5–37.3) | 33.6 (27.9–40.4) | 32.9 (27.3–39.7) | 32.4 (26.8–39.1) | 28.8 (23.6–35.2) | 39.3 (33.1–46.6) | 41.8 (35.4–49.3) | 43.1 (36.7–50.7) |
| 10–14 years | 26.8 (22.1–32.5) | 29.3 (24.3–35.3) | 33.3 (27.9–39.8) | 32.2 (26.9–38.6) | 32.1 (26.7–38.5) | 36.7 (30.9–43.6) | 34.5 (28.9–41.3) | 37.6 (31.7–44.6) |
| 15–19 years | 11.8 (8.8–15.9) | 9.9 (7.1–13.6) | 9.7 (7.0–13.4) | 7.9 (5.5–11.2) | 11.4 (8.5–15.4) | 11.9 (8.9–15.9) | 12.3 (9.2–16.3) | 11.0 (8.1–15.0) |
| Total | 22.8 (20.5–25.4) | 23.9 (21.5–26.6) | 23.2 (20.8–25.9) | 22.1 (19.8–24.7) | 23.1 (20.7–25.8) | 26.1 (23.5–28.9) | 26.3 (23.7–29.1) | 26.7 (24.1–29.5) |
| Total, age-adjusted | 22.8 (22.2–23.4) | 23.8 (23.2–24.5) | 23.2 (22.6–23.8) | 22.1 (21.5–22.7) | 23.1 (22.5–23.7) | 26.0 (25.3–26.7) | 26.2 (25.6–26.9) | 26.6 (25.9–27.3) |
| Males | ||||||||
| n | 388 | 345 | 348 | 402 | 405 | 406 | 426 | 412 |
| Age at diagnosis (years) | 10.09 (4.51) | 9.93 (4.78) | 9.93 (4.84) | 10.22 (4.55) | 10.23 (4.73) | 10.35 (4.33) | 10.11 (4.57) | 10.04 (4.67) |
| Incidence by age category | ||||||||
| 0–4 years | 18.4 (14.4–23.6) | 21.5 (17.1–27.0) | 19.7 (15.5–25.0) | 18.4 (14.4–23.6) | 19.3 (15.1–24.5) | 16.4 (12.6–21.3) | 21.8 (17.4–27.3) | 21.0 (16.7–26.5) |
| 5–9 years | 32.1 (26.8–38.5) | 21.7 (17.4–27.1) | 29.7 (24.6–36.0) | 34.0 (28.4–40.7) | 34.4 (28.8–41.1) | 36.5 (30.7–43.4) | 34.2 (28.6–40.8) | 34.4 (28.9–41.1) |
| 10–14 years | 35.9 (30.5–42.3) | 37.3 (31.7–43.8) | 30.2 (25.2–36.1) | 43.1 (37.0–50.2) | 39.0 (33.2–45.8) | 42.5 (36.4–49.6) | 44.9 (38.6–52.3) | 39.3 (33.4–46.3) |
| 15–19 years | 16.5 (12.9–21.1) | 11.9 (8.9–15.8) | 15.2 (11.8–19.6) | 14.4 (11.1–18.7) | 18.0 (14.3–22.7) | 16.2 (12.7–20.7) | 16.5 (13.0–21.0) | 18.4 (14.6–23.2) |
| Total | 25.9 (23.5–28.6) | 23.2 (20.9–25.8) | 23.7 (21.3–26.3) | 27.5 (24.9–30.3) | 27.6 (25.1–30.5) | 27.8 (25.2–30.7) | 29.2 (26.6–32.1) | 28.2 (25.6–31.1) |
| Total, age-adjusted | 25.9 (25.3–26.5) | 23.2 (22.6–23.8) | 23.6 (23.0–24.2) | 27.4 (26.8–28.1) | 27.6 (27.0–28.3) | 27.8 (27.1–28.4) | 29.2 (28.5–29.8) | 28.2 (27.5–28.9) |
Data are incidence per 100,000 person-years (95% CI) or mean (SD) unless otherwise indicated. All age- and sex-adjusted rates were calculated by using direct adjustment, with the estimated 2002–2009 U.S. intercensal population as the standard population.
*Age at diagnosis.