Incidence per 1000 Persons for ADHD Medication Among Girls Born 2005–2007 by Birth Month
Age, y . | No. Cases and Incidence (95% CI) January to April . | No. Cases and Incidence (95% CI) May to August . | No. Cases and Incidence (95% CI) September to December . | IRR (95% CI) . | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
2005 . | 2006 . | 2007 . | 2005 . | 2006 . | 2007 . | 2005 . | 2006 . | 2007 . | 2005 September to December versus 2006 January to April . | 2006 September to December versus 2007 January to April . | |
6 | 6; 0.6 (0.2–1.3) | 11; 1.1 (0.6–1.9) | 12; 1.2 (0.7–2.0) | 18; 1.8 (1.1–2.7) | 19; 1.8 (1.1–2.8) | 23; 2.3 (1.5–3.3) | 14; 1.5 (0.8–2.4) | 14; 1.4 (0.8–2.4) | 26; 2.7 (1.8–3.9) | 1.33 (0.60–3.01) | 1.19 (0.55–2.64) |
7 | 18; 1.8 (1.1–2.9) | 11; 1.1 (0.6–1.9) | 14; 1.4 (0.8–2.3) | 23; 2.3 (1.5–3.3) | 27; 2.6 (1.8–3.8) | 31; 3.0 (2.1–4.3) | 26; 2.7 (1.8–3.9) | 38; 3.9 (2.8–5.3) | 45; 4.7 (3.4–6.2) | 2.46 (1.23–5.19)a | 2.78 (1.53–5.29)a |
8 | 17; 1.7 (1.0–2.7) | 21; 2.1 (1.3–3.2) | 29; 2.9 (2.0–4.1) | 31; 3.0 (2.1–4.3) | 36; 3.5 (2.5–4.8) | 42; 4.1 (3.0–5.5) | 41; 4.3 (3.1–5.7) | 35; 3.6 (2.5–4.9) | 36; 3.7 (2.7–5.1) | 2.04 (1.21–3.50)a | 1.24 (0.75–2.04) |
9 | 26; 2.7 (1.8–3.9) | 22; 2.2 (1.3–3.2) | 25; 2.5 (1.7–3.6) | 34; 3.3 (2.4–4.6) | 33; 3.2 (2.2–4.4) | 45; 4.4 (3.3– 5.8) | 31; 3.2 (2.2–4.5) | 36; 3.7 (2.6–5.1) | 47; 4.9 (3.6–6.4) | 1.47 (0.85–2.57) | 1.47 (0.89–2.48) |
10 | 20; 2.1 (1.3–3.1) | 19; 1.9 (1.2–2.9) | 18; 1.8 (1.1–2.8) | 17; 1.7 (1.0–2.6) | 25; 2.4 (1.6–3.5) | 19; 1.9 (1.2–2.9) | 26; 2.7 (1.8–3.9) | 24; 2.5 (1.6–3.6) | 7; 0.7 (0.3–1.4) | 1.43 (0.79–2.62) | 1.37 (0.74–2.55) |
11 | 17; 1.8 (1.0–2.7) | 15; 1.5 (0.9–2.4) | — | 28; 2.8 (1.9–3.9) | 9; 0.9 (0.4–1.6) | — | 30; 3.1 (2.1–4.4) | 6; 0.6 (0.2–1.3) | — | 2.09 (1.13–3.97)a | — |
12 | 18; 1.9 (1.1–2.9) | — | — | 14; 1.4 (0.8–2.3) | — | — | 4; 0.4 (0.1–1.0) | — | — | — | — |
Age, y . | No. Cases and Incidence (95% CI) January to April . | No. Cases and Incidence (95% CI) May to August . | No. Cases and Incidence (95% CI) September to December . | IRR (95% CI) . | |||||||
---|---|---|---|---|---|---|---|---|---|---|---|
2005 . | 2006 . | 2007 . | 2005 . | 2006 . | 2007 . | 2005 . | 2006 . | 2007 . | 2005 September to December versus 2006 January to April . | 2006 September to December versus 2007 January to April . | |
6 | 6; 0.6 (0.2–1.3) | 11; 1.1 (0.6–1.9) | 12; 1.2 (0.7–2.0) | 18; 1.8 (1.1–2.7) | 19; 1.8 (1.1–2.8) | 23; 2.3 (1.5–3.3) | 14; 1.5 (0.8–2.4) | 14; 1.4 (0.8–2.4) | 26; 2.7 (1.8–3.9) | 1.33 (0.60–3.01) | 1.19 (0.55–2.64) |
7 | 18; 1.8 (1.1–2.9) | 11; 1.1 (0.6–1.9) | 14; 1.4 (0.8–2.3) | 23; 2.3 (1.5–3.3) | 27; 2.6 (1.8–3.8) | 31; 3.0 (2.1–4.3) | 26; 2.7 (1.8–3.9) | 38; 3.9 (2.8–5.3) | 45; 4.7 (3.4–6.2) | 2.46 (1.23–5.19)a | 2.78 (1.53–5.29)a |
8 | 17; 1.7 (1.0–2.7) | 21; 2.1 (1.3–3.2) | 29; 2.9 (2.0–4.1) | 31; 3.0 (2.1–4.3) | 36; 3.5 (2.5–4.8) | 42; 4.1 (3.0–5.5) | 41; 4.3 (3.1–5.7) | 35; 3.6 (2.5–4.9) | 36; 3.7 (2.7–5.1) | 2.04 (1.21–3.50)a | 1.24 (0.75–2.04) |
9 | 26; 2.7 (1.8–3.9) | 22; 2.2 (1.3–3.2) | 25; 2.5 (1.7–3.6) | 34; 3.3 (2.4–4.6) | 33; 3.2 (2.2–4.4) | 45; 4.4 (3.3– 5.8) | 31; 3.2 (2.2–4.5) | 36; 3.7 (2.6–5.1) | 47; 4.9 (3.6–6.4) | 1.47 (0.85–2.57) | 1.47 (0.89–2.48) |
10 | 20; 2.1 (1.3–3.1) | 19; 1.9 (1.2–2.9) | 18; 1.8 (1.1–2.8) | 17; 1.7 (1.0–2.6) | 25; 2.4 (1.6–3.5) | 19; 1.9 (1.2–2.9) | 26; 2.7 (1.8–3.9) | 24; 2.5 (1.6–3.6) | 7; 0.7 (0.3–1.4) | 1.43 (0.79–2.62) | 1.37 (0.74–2.55) |
11 | 17; 1.8 (1.0–2.7) | 15; 1.5 (0.9–2.4) | — | 28; 2.8 (1.9–3.9) | 9; 0.9 (0.4–1.6) | — | 30; 3.1 (2.1–4.4) | 6; 0.6 (0.2–1.3) | — | 2.09 (1.13–3.97)a | — |
12 | 18; 1.9 (1.1–2.9) | — | — | 14; 1.4 (0.8–2.3) | — | — | 4; 0.4 (0.1–1.0) | — | — | — | — |
IRR are between girls born in the last third of the year (September to December) and girls born in the first third (January to April; reference category) of the following year. CI, confidence interval; —, not applicable.
IRR is significant at P < .05.