Sensitivity analyses for risk of receiving a diagnosis of attention-deficit/hyperactivity disorder or treatment for the condition for children aged 6–12 years who were born in different periods
| Exposed cohort | Unexposed cohort | RD (95% CI) | RR (95% CI) | |
|---|---|---|---|---|
| Analysis 1, date of birth | Dec. 17–31 | Jan. 1–15 | ||
| Boys, no. | 14 853 | 15 068 | ||
| Diagnosis, no. (%) | 1 085 (7.3) | 856 (5.7) | 1.62 (1.07 to 2.18) | 1.29 (1.18 to 1.40) |
| Treatment, no. (%) | 884 (6.0) | 666 (4.4) | 1.53 (1.03 to 2.03) | 1.35 (1.22 to 1.49) |
| Girls, no. | 13 960 | 14 529 | ||
| Diagnosis, no. (%) | 376 (2.7) | 231 (1.6) | 1.10 (0.77 to 1.44) | 1.69 (1.44 to 1.99) |
| Treatment, no. (%) | 261 (1.9) | 150 (1.0) | 0.84 (0.56 to 1.12) | 1.81 (1.48 to 2.21) |
| Analysis 2, date of birth | Dec. 2–16 | Dec. 17–31 | ||
| Boys, no. | 18 957 | 14 853 | ||
| Diagnosis, no. (%) | 1 420 (7.5) | 1 085 (7.3) | 0.19 (−0.38 to 0.75) | 1.03 (0.95 to 1.11) |
| Treatment, no. (%) | 1 190 (6.3) | 884 (6.0) | 0.33 (−0.19 to 0.84) | 1.05 (0.97 to 1.15) |
| Girls, no. | 17 924 | 13 960 | ||
| Diagnosis, no. (%) | 469 (2.6) | 376 (2.7) | −0.08 (−0.43 to 0.28) | 0.97 (0.85 to 1.11) |
| Treatment, no. (%) | 347 (1.9) | 261 (1.9) | 0.07 (−0.24 to 0.37) | 1.04 (0.88 to 1.21) |
| Analysis 3, date of birth | Jan. 1–15 | Jan. 16–30 | ||
| Boys, no. | 15 068 | 19 154 | ||
| Diagnosis, no. (%) | 856 (5.7) | 1 103 (5.8) | −0.08 (−0.57 to 0.42) | 0.99 (0.90 to 1.08) |
| Treatment, no. (%) | 666 (4.4) | 837 (4.4) | 0.05 (−0.39 to 0.49) | 1.01 (0.92 to 1.12) |
| Girls, no. | 14 529 | 18 179 | ||
| Diagnosis, no. (%) | 231 (1.6) | 276 (1.5) | 0.07 (−0.20 to 0.34) | 1.05 (0.88 to 1.25) |
| Treatment, no. (%) | 150 (1.0) | 194 (1.1) | −0.03 (−0.26 to 0.19) | 0.97 (0.78 to 1.20) |
| Analysis 4, date of birth | Dec. 29–31 | Jan. 1–3 | ||
| Boys, no. | 3 907 | 3 609 | ||
| Diagnosis, no. (%) | 272 (6.7) | 190 (5.3) | 1.70 (0.62 to 2.78) | 1.32 (1.10 to 1.58) |
| Treatment, no. (%) | 252 (6.5) | 155 (4.3) | 2.16 (1.14 to 3.17) | 1.50 (1.24 to 1.82) |
| Girls, no. | 3 710 | 3 491 | ||
| Diagnosis, no. (%) | 93 (2.5) | 59 (1.7) | 0.82 (0.16 to 1.48) | 1.48 (1.07 to 2.05) |
| Treatment, no. (%) | 74 (2.0) | 49 (1.4) | 0.59 (0.00 to 1.19) | 1.42 (0.99 to 2.03) |
Note: CI = confidence interval, RD = risk difference, RR = relative risk.