Table 2 Prevalence and cumulative incidence of autism spectrum disorders for each study year and for the total study years

Ascertained cases

male

14

13

18

15

60

female

8

7

7

5

27

total

22

20

25

20

87

N of children with ASD born in the catchment area

male

8

9

14

13

44

female

5

7

6

5

23

total

13

16

20

18

67

A total N of 5-year-old children in the catchment area

male

685

639

600

625

2549

female

625

622

621

599

2467

total

1310

1261

1221

1224

5016

N of 5-year-old whose caregivers returned the screening questionnaire

male

506

496

489

531

2022

female

449

468

515

500

1932

total

954

964

1004

1031

3954

N of the birth cohort in the catchment area

male

703

648

639

603

2593

female

656

610

664

589

2519

total

1359

1258

1303

1192

5112

Crude orevalence (%) (95% confidence interval: CI)

male

2.04 (0.98–3.10)

2.03 (0.94–3.13)

3.00 (1.64–4.36)

2.82 (1.42–4.23)

2.35 (1.76–2.94)

female

1.28 (0.40–2.16)

1.13 (0.30–1.95)

1.13 (0.30–1.96)

0.83 (0.11–1.56)

1.09 (0.68–1.51)

total

1.68 (0.98–2.38)

1.59 (0.90–2.28)

2.05 (1.25–2.84)

1.63 (0.92–2.34)

1.73 (1.37–2.10)

Adjusted prevalence (%) (95% CI)

male

–

–

–

–

4.06 (3.20–4.92)

female

–

–

–

–

2.22 (1.57–2.88)

total

–

–

–

–

3.22 (2.66–3.76)

Cumulative incidence up to 5 years of age (%) (95% CI)

male

1.14 (0.35–1.92)

1.39 (0.49–2.29)

2.19 (1.06–3.33)

2.16 (1.00–3.32)

1.70 (1.20–2.19)

female

0.76 (0.10–1.43)

1.15 (0.30–1.99)

0.90 (0.18–1.62)

0.85 (0.11–1.59)

0.91 (0.54–1.28)

total

0.96 (0.44–1.47)

1.27 (0.65–1.89)

1.53 (0.87–2.20)

1.51 (0.82–2.20)

1.31 (1.00–1.62)