Table 3

Crude rates of first diagnosis (per 10 000 person-years) and age standardised incidence ratios for autism and other PDDs by year of diagnosis
year
 Total cases
 Cases with 'other PDD' diagnosis
 % cases with 'other PDD' diagnosis
 incidence other PDDs
 incidence autism
 SIR other PDDs
 SIR autism
1988
 1
 0
 0
 0
 0.11
 0
 10
1989
 6
 0
 0
 0
 0.23
 0
 23
1990
 21
 0
 0
 0
 0.33
 0
 35
1991
 45
 0
 0
 0
 0.40
 0
 44
1992
 45
 0
 0
 0
 0.34
 0
 39
1993
 69
 2
 3
 0.01
 0.49
 6
 58
1994
 77
 2
 3
 0.01
 0.52
 6
 64
1995
 108
 3
 3
 0.02
 0.71
 9
 91
1996
 102
 8
 8
 0.06
 0.68
 27
 92
1997
 133
 18
 14
 0.14
 0.90
 67
 128
1998
 192
 51
 27
 0.42
 1.15
 204
 173
1999
 231
 87
 38
 0.78
 1.28
 369
 200
2000
 211
 82
 39
 0.88
 1.38
 435
 225
2001
 169
 60
 36
 1.06
 1.92
 495
 319

Smeeth et al. BMC Medicine 2004 2:39   doi:10.1186/1741-7015-2-39