Table 1.
Study sample characteristics and mean child Social Responsiveness Scale (SRS) total T-Scores at 3 to 8 years according to covariates: the EARLI (2009–2012) and HOME Studies (2003–2006).
| Variable | SRS T-Scores | |||
|---|---|---|---|---|
| EARLI | HOME | EARLI | HOME | |
| N (%) | N (%) | Mean (SD) | Mean (SD) | |
| Overall | 140 (100) | 276 (100) | 48 (11) | 52 (10) |
| Maternal Age | ||||
| <25 years | 2 (1) | 59 (21) | 48 (1.4) | 57 (12) |
| 25–<35 years | 68 (49) | 170 (62) | 50 (13) | 50 (8.1) |
| 35+ years | 70 (50) | 47 (17) | 46 (7.6) | 52 (13) |
| Maternal Race | ||||
| White | 95 (68) | 178 (64) | 48 (10) | 49 (8.5) |
| Non-White | 45 (32) | 98 (36) | 48 (12) | 57 (12) |
| Maternal Education | ||||
| High School or less | 14 (10) | 64 (23) | 50 (10) | 58 (12) |
| Some College | 40 (29) | 75 (27) | 53 (15) | 53 (9.4) |
| Completed College | 86 (61) | 137 (50) | 45 (7.5) | 48 (8.3) |
| Annual Income | ||||
| <$30,000 | 15 (11) | 87 (32) | 53 (17) | 58 (12) |
| $30,000–$75,000 | 42 (30) | 87 (32) | 50 (12) | 50 (8.9) |
| ≥$75,000 | 83 (59) | 102 (36) | 46 (7.9) | 47 (7.4) |
| Maternal Smoking 1,2 | ||||
| Non-Smoking | 132 (94) | 245 (89) | 47 (10) | 52 (11) |
| Active Smoking | 8 (6) | 31 (11) | 60 (19) | 55 (8.7) |
| Parity 3 | ||||
| 0 | -- | 128 (46) | -- | 51 (10) |
| 1 | 66 (47) | 86 (31) | 49 (12) | 51 (10) |
| 2+ | 74 (53) | 62 (23) | 47 (10) | 55 (11) |
| Pre-pregnancy BMI (kg/m2) | ||||
| Normal/Underweight <25 | 54 (39) | 142 (51) | 45 (8.5) | 50 (11) |
| Overweight ≥25–<30 | 40 (29) | 69 (25) | 47 (9.0) | 51 (8.2) |
| Obese ≥30 | 46 (33) | 65 (24) | 52 (13) | 55 (12) |
| Child Sex | ||||
| Male | 77 (55) | 123 (45) | 50 (13) | 51 (9.7) |
| Female | 63 (45) | 153 (55) | 45 (6.9) | 53 (11) |
BMI: body mass index, EARLI: Early Autism Risk Longitudinal Investigation Study, HOME: Health Outcomes and Measures of the Environment Study, SRS: Social Responsiveness Scale. 1 Maternal smoking during pregnancy for EARLI was based on maternal urinary cotinine concentrations (a metabolite of nicotine) during pregnancy. The cut off point of 50 ng/mL was used to differentiate between non-smoking and active smoking [62] 2 Maternal smoking during pregnancy for HOME estimated based on maternal serum cotinine concentrations during pregnancy. The cut off point of 3.0 ng/mL was used to differentiate non-smoking and active smoking [61]. 3 Note that for parity, the EARLI cohort consists of mothers who had at least one previous child.