Supplementary Table 1: Composition of the diagnostic categories
Existing categories from our
Outpatient file
Substance abuse disorders
Our categories for the
analyses
‘Substance abuse disorders’
Schizophrenia, paranoia & acute
psychotic disorders
Mood disorders
Anxiety disorders
‘Schizophrenia, paranoia
and acute psychoses’
ICD 9 codes contained in the category
ICD10 codes contained in the category
291.0, 291.2, 291.8, 291.9, 292.0, 292.8,
292.9, 294.0, 303.0, 303.9, 304.0–304.9,
305.0, 305.2–305.9
291.3-291.5, 295, 297, 298
F10–F19
F55
296.0–296.9, 311, 316
300.0, 300.2, 300.4, 300.5, 300.8, 300.9
F30–F39, F54
F20.4, F34.1, F40–F41, F45.0, F45.1,
F48
F43, F94.0
F42
‘Affective disorders’
Stress and adjustment disorders
Obsessive-compulsive disorders
Personality disorders
Mental retardation, Psychological
development disorders
Childhood and adolescent
disorders
‘Obsessive-compulsive and
personality disorders’
‘Developmental disorders’
‘Childhood and adolescent
disorders’
Organic disorders
Unspecified mental health
conditions
301, 312.4, 312.8, 312.9
299.0, 299.1, 299.8, 299.9, 315, 317-319
307, 312, 313, 314, 330.8
290.0–290.4, 290.8, 290.9 291.1, 293,
294.1, 294.8, 294.9, 298.9, 300.10, 310.0–
310.2, 310.1, 310.8, 310.9
300.6, 300.7
307.1, 307.5
305.1, 306, 307.4, 316.0, 316.9
Somatoform disorders
Eating disorders
Behavioural syndromes
Sexual disorders
Other related mental health
conditions
308.0–308.4, 309
300.3
‘Other mental health
diagnoses’
302
331.0, 368.16, 648.4, 648.4,
655.45, 655.53, 780.1, 780.5, 784.6,
785.50, 799
799.9
F20–F29
F60, F61, F62, F68, F69, F91, F92
F70, F71, F72, F73, F78, F79 F80–F84,
F88–F89
F45.4, F45.8, F63, F84.2, F90, F91.1,
F91.2, F93, F94.1, F94.2, F94.8, F94.9,
F95, F98.0, F98.1, F98.4, F98.5,
F98.6 , F98.8, F98.9
F00-F07, F09, F10.6, F44, F68.0
F45.2, F48.1
F54.9, F50, F98.2, F98.3
F17.0, F17.1, F45.3, F45.9, F51, F52.5,
F53.0, F53.1, F53.8, F53.9, F59
F52, F64, F65, F66
G30.0, G47, O35.4, O35.5, O99.3, R44,
R45, R48
F99
Supplementary Table 2: Association of socio-demographic variables with each case group outcome, adjusted for ‘any contact’, ORs (95% CIs)
and p-values.
Maternal case groups
Characteristic
Mild-moderate ID
Socio-economic status at the index birth
Low
Reference group
Medium
1.54(1.4, 1.7)
<0.0005
High
0.65(0.6, 0 .7)
<0.0005
Maternal age in years at the index birth
< 20
2.03(1.8, 2.3)
<0.0005
20-29
Reference group
30-39
0.51(0.5, 0.5)
<0.0005
≥ 40
0.27(0.2, 0.4)
<0.0005
Parity at the index birth
0
Reference group
1
2-3
>3
5.32(4.9, 5.8)
<0.0005
7.90(7.2, 8.7)
<0.0005
17.44(15, 20.5)
<0.0005
Index birth year group
1983-87
Reference group
1988-91
1992-95
1996-99
3.36(3.1, 3.7)
<0.0005
3.67(3.3, 4.1)
<0.0005
1.76(1.6, 2.0)
<0.0005
Severe ID
Down syndrome
ID of known cause (not
Down)
ASD with ID
ASD without
ID
Reference group
Reference group
Reference group
Reference group
Reference group
1.57(1.1, 2.2)
0.006
0.87(0.6, 1.3)
0.495
0.75(0.5, 1.01)
0.061
0.89(0.7, 1.2)
0.397
1.31(1.1, 1.6)
0.014
0.90(0.7, 1.1)
0.387
0.98(0.8, 1.2)
0.817
0.88(0.7, 1.1)
0.236
0.60(0.5, 0.8)
<0.0005
0.86(0.7, 1.1)
0.258
1.16(0.7, 2.0)
0.584
Reference group
0.62(0.3, 1.4)
0.260
Reference group
1.35(0.97, 1.9)
0.078
Reference group
0.49(0.3, 0.8)
0.007
Reference group
0.85(0.5, 1.4)
0.522
Reference group
0.67(0.5, 0.9)
0.008
0.44(0.2, 1.2)
0.109
1.38(1.1, 1.8)
0.009
3.49(2.4, 5.2)
<0.0005
0.70(0.6, 0.8)
<0.0005
0.73(0.4, 1.2)
0.237
1.27(1.1, 1.5)
0.005
1.07(0.7, 1.7)
0.774
1.19(0.96, 1.5)
0.112
0.80(0.4, 1.5)
0.520
Reference group
Reference group
Reference group
Reference group
Reference group
3.79(2.8, 5.2)
<0.0005
4.66(3.3, 6.6)
<0.0005
7.79(4.1, 15.0)
<0.0005
5.96(4.5, 7.9)
<0.0005
7.07(5.2, 9.6)
<0.0005
17.95(11.8, 27.2)
<0.0005
3.45(2.8, 4.3)
<0.0005
5.09(4.0, 6.4)
<0.0005
7.50(4.9, 11.6)
<0.0005
4.75(4.0, 5.7)
<0.0005
3.54(2.8, 4.5)
<0.0005
3.39(2.0, 5.9)
<0.0005
3.71(2.9, 4.7)
<0.0005
2.82(2.1, 3.9)
<0.0005
3.15(1.5, 6.5)
<0.0005
Reference group
Reference group
Reference group
Reference group
Reference group
2.58(1.9, 3.6)
<0.0005
1.62(1.1, 2.4)
0.017
1.59(1.1, 2.4)
0.025
2.62(1.9, 3.5)
<0.0005
3.47(2.6, 4.7)
<0.0005
2.75(2.0, 3.8)
<0.0005
1.96(1.5, 2.5)
<0.0005
2.11(1.6, 2.7)
<0.0005
2.26(1.8, 2.9)
<0.0005
4.45(3.3, 6.0)
<0.0005
6.74(5.0, 9.1)
<0.0005
12.44(9.4, 16.4)
<0.0005
3.7(2.5, 5.4)
<0.0005
7.99(5.6, 11.4)
<0.0005
7.45(5.2, 10.7)
<0.0005
ID, intellectual disability; Mild-moderate ID, Mild or moderate ID of unknown cause; Severe ID, Severe or profound ID of unknown cause;
ASD, Autism spectrum disorder.
Supplementary Table 3: Causes in ID of known cause (not Down syndrome) case group
Basis of ID*
Defects of CNS and other congenital defects
Genetic: X-linked, autosomal and chromosomal
Neo-natal and post-neonatal events
Teratogens: chemical and infectious
TOTAL
Number
71
263
47
40
421
Percentage
17
62
11
10
100
*Medical diagnosis categories based on the Heber classification (Heber, 1961) and metabolic
causes have been incorporated into the genetic category.