Table 2.
Prevalence of autism spectrum disorder for each birth year from Child and Adolescent Twin Study in Sweden and national patient register
| Data sources | Prevalence (95% CI) per birth year | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | |
| Child and Adolescent Twin Study in Sweden | ||||||||||
| Cut-off scores: | ||||||||||
| ≥8.5 | 0.52 (0.23 to 0.82) | 1.59 (1.06 to 2.12) | 0.82 (0.43 to 1.21) | 0.87 (0.46 to 1.29) | 1.12 (0.67 to 1.58) | 1.24 (0.74 to 1.74) | 0.70 (0.34 to 1.07) | 0.76 (0.36 to 1.16) | 0.69 (0.32 to 1.07) | 1.19 (0.71 to 1.67) |
| ≥4.5 | 2.96 (2.27 to 3.65) | 4.45 (3.58 to 5.33) | 3.19 (2.43 to 3.95) | 2.52 (1.82 to 3.22) | 3.32 (2.62 to 4.19) | 3.18 (2.38 to 3.97) | 3.56 (2.75 to 4.83) | 2.93 (2.16 to 3.71) | 3.25 (2.45 to 4.05) | 4.19 (3.30 to 5.08) |
| Autism score* | 0.73 (0.68 to 0.79) | 0.84 (0.76 to 0.91) | 0.77 (0.71 to 0.84) | 0.72 (0.65 to 0.78) | 0.73 (0.66 to 0.80) | 0.79 (0.71 to 0.86) | 0.77 (0.71 to 0.84) | 0.67 (0.61 to 0.74) | 0.74 (0.67 to 0.80) | 0.86 (0.78 to 0.93) |
| National patient register | ||||||||||
| Registered diagnosis | 0.23 (0.21 to 0.26) | 0.30 (0.27 to 0.33) | 0.32 (0.28 to 0.35) | 0.39 (0.35 to 0.42) | 0.45 (0.41 to 0.49) | 0.47 (0.43 to 0.52) | 0.60 (0.55 to 0.65) | 0.60 (0.55 to 0.65) | 0.53 (0.48 to 0.57) | 0.50 (0.46 to 0.54) |
*Based on same number of participants as for cut-offs scores of ≥8.5 and ≥4.5.