Table 1.
Comparison of ASD and TD control groups with respect to characteristics of children and their parents (344 matched pairs).
| Variables | Categories | ASD Cases (n = 344) n (%) |
TD Controls (n = 344) n (%) |
p Value * | |
|---|---|---|---|---|---|
| Child | Sex | Male | 286 (83.1) | 286 (83.1) | 1.00 |
| Age | < 48 months | 97 (28.2) | 87 (25.3) | 0.02 | |
| ≥ 48 months | 247 (71.8) | 257 (74.7) | |||
| Race | Afro-Caribbean | 325 (94.5) | 334 (97.1) | 0.10 | |
|
Place of birth
(Parish) |
Kingston | 102 (29.6) | 216 (62.8) | <0.01 | |
| Others a | 242 (70.4) | 128 (37.2) | |||
|
Mother’s age b
(at child’s birth) |
Age < 35 years | 276 (80.5) | 298 (88.2) | <0.01 | |
| Age ≥ 35 years | 67 (19.5) | 40 (11.8) | |||
|
Father’s age c
(at child’s birth) |
Age < 35 years | 190 (56.2) | 230 (69.7) | <0.01 | |
| Age ≥ 35 years | 148 (43.8) | 100 (30.3) | |||
|
Parental education d
(at child’s birth) |
Both up to high school † | 128 (37.7) | 169 (51.7) | <0.01 | |
| At least one beyond high school †† | 210 (62.3) | 158 (48.3) | |||
| Socioeconomic status (SES) | Car ownership | 186 (54.1) | 144 (41.9) | <0.01 | |
| GSTP1 e | Ile/Ile | 86 (25.2) | 91 (26.5) | 0.48 | |
| Ile/Val | 190 (55.7) | 175 (51.0) | |||
| Val/Val | 65 (19.1) | 77 (22.4) | |||
| GSTM1 f | DD g | 103 (30.3) | 82 (24.0) | 0.07 | |
| I/I or I/D h | 237 (69.7) | 259 (76.0) | |||
| GSTT1 i | DD g | 84 (24.6) | 88 (25.9) | 0.60 | |
| I/I or I/D h | 257 (75.4) | 252 (74.1) | |||
* p values are based on Wald’s test in conditional logistic regression models. † Up to high school education refers to those who attended primary/jr. secondary, and secondary/high/technical schools. †† Beyond high school education indicates those who attended a vocational or tertiary college or university. a Other parishes include all 12 parishes in Jamaica, except for Kingston parish as described previously [53]. b Mother’s age was missing for 1 ASD case and 6 TD control children. c Father’s age was missing for 6 ASD case and 14 TD control children. d Parental education was missing for 7 ASD case and 17 TD control children. e GSTP1 genotype was missing for 3 ASD case and 1 TD control children. f GSTM1 genotype was missing for 4 ASD case and 3 TD control children. g DD indicates the null alleles for GSTT1 and GSTM1. h I/I or I/D indicate the homozygote (I/I) or a heterozygote (I/D) for GSTT1 and GSTM1. i GSTT1 was missing for 3 ASD case and 4 TD control children.