Table 1.
Sociodemographic characteristics of the mother-child pairs and distributions of six phthalate metabolites during pregnancy in the analytic sample of HOME and EARLI (N = 437).
| HOME (N=271) | EARLI (N=166) | Pooled (N=437) | |
|---|---|---|---|
| MATERNAL CHARACTERISTICS | |||
| Maternal age at delivery (years) | 29.0 (19.0, 45.0) | 34.0 (22.0, 44.0) | 32.0 (19.0, 45.0) |
| Maternal race/ethnicity, n(%) | |||
| Hispanic or Latino | 7 (3%) | 33 (20%) | 40 (9%) |
| Non-Hispanic black | 84 (31%) | 15 (9%) | 99 (23%) |
| Non-Hispanic white | 168 (62%) | 92 (55%) | 260 (59%) |
| Other/multiple races | 12 (4%) | 26 (16%) | 38 (9%) |
| Parity a | |||
| 0–2 | 251 (93%) | 136 (82%) | 387 (89%) |
| >2 | 20 (7%) | 30 (18%) | 50 (11%) |
| Pre-pregnancy BMI (kg/m2) | 24.7 (15.8, 51.3) | 26.6 (17.8, 58.4) | 25.5 (15.8, 58.4) |
| Household annual income, $; n(%) | |||
| 0–10,000 | 46 (17%) | 6 (4%) | 52 (12%) |
| 10,001–20,000 | 19 (7%) | 4 (2%) | 23 (5%) |
| 20,001–30,000 | 20 (7%) | 7 (4%) | 27 (6%) |
| 30,001–50,000 | 42 (16%) | 24 (14%) | 66 (15%) |
| 50,001–75,000 | 42 (16%) | 29 (18%) | 71 (16%) |
| 75,001–100,000 | 58 (21%) | 31 (19%) | 89 (20%) |
| 100,001–200,000 | 44 (16%) | 53 (32%) | 97 (22%) |
| >200,000 | 0 (0%) | 12 (7%) | 12 (3%) |
| MBP (ug/g creatinine), median (min, max) | 26.3 (4.5, 557.0) | 14.5 (2.2, 217.6) | 21.6 (2.2, 557.0) |
| MBzP (ug/g creatinine), median (min, max) | 11.1 (0.6, 185.1) | 6.7 (0.3, 238.6) | 9.2 (0.3, 238.6) |
| MCPP (ug/g creatinine), median (min, max) | 2.4 (0.6, 55.2) | 2.4 (0.4, 2811.1) | 2.4 (0.4, 2811.1) |
| DEHP (ug/g creatinine), median (min, max) b | 88.0 (16.3, 3809.8) | 41.3 (7.4, 1135.7) | 63.6 (7.4, 3809.8) |
| MEP (ug/g creatinine), median (min, max) | 152.3 (11.1, 9158.9) | 34.5 (2.5, 2279.4) | 94.0 (2.5, 9158.9) |
| MiBP (ug/g creatinine), median (min, max) | 5.3 (0.8, 48.3) | 10.3 (1.8, 317.7) | 6.9 (0.8, 317.7) |
| CHILD CHARACTERISTICS | |||
| Child sex at birth, n(%) | |||
| Female | 149 (55%) | 76 (46%) | 225 (52%) |
| Male | 122 (45%) | 90 (54%) | 212 (48%) |
| Age at SRS administration (months), median (min, max) | 50.1 (45.2, 125.2) | 36.3 (35.0, 50.2) | 48.6 (35.0, 125.2) |
| SRS total raw scores (points), median (min, max) c | 30.0 (1.0, 126.0) | 29.0 (6.0, 174.0) | 30.0 (1.0, 174.0) |
| SRS total T-scores (unitless), median (min, max) | 50.0 (35.0, 90.0) | 45.0 (36.0, 101.0) | 48.0 (35.0, 101.0) |
| STUDY SITE, n(%) | |||
| HOME | 271 (100%) | 0 (0%) | 271 (62%) |
| Drexel | 0 (0%) | 41 (25%) | 41 (9%) |
| Johns Hopkins University | 0 (0%) | 39 (23%) | 39 (9%) |
| Kaiser Permanente | 0 (0%) | 58 (35%) | 58 (13%) |
| UC Davis | 0 (0%) | 28 (17%) | 28 (6%) |
All the pregnant women in EARLI had prior pregnancies by study design.
DEHP (ug/g creatinine) was calculated as ΣDEHP (ug/g creatinine) = [MEHP (ug/g creatinine)/278 (g/mol) + MEOHP (ug/g creatinine)/292 (g/mol) + MEHHP (ug/g creatinine)/294 (g/mol) + MECPP (ug/g creatinine)/308 (g/mol)] × 308 g/mol where 278, 292, 294, and 308 are the molecular weights of mono-2-ethylhexyl phthalate (MEHP), mono-2-ethyl-5-oxohexyl phthalate (MEOHP), mono-2-ethyl-5-hydroxyhexyl phthalate (MEHHP), mono-2-ethyl-5-carboxypentyl phthalate (MECPP), respectively.
SRS had 65 items, each of which was scored as 0 (“not true”), 1 (“sometimes true”), 2 (“often true”), or 3 (“almost always true”). The total raw score was a sum of all these 65 items.
All values are sample sizes (column percentages) for categorial variables and medians (minimums, maximums) for continuous variables unless otherwise specified. Maternal urinary phthalates concentrations were imputed with the lower limit of detection (LLOD) divided by square root of two if lower than the LLOD and corrected for urinary dilution using creatinine.
BMI, body mass index; DEHP, di(2-ethylhexyl) phthalate; EARLI, the Early Autism Risk Longitudinal Investigation Study; HOME, the Health Outcomes and Measures of the Environment Study; MBP, mono-n-butyl phthalate; MBzP, monobenzyl phthalate; MCPP, mono-3-carboxypropyl phthalate; MEP, monoethyl phthalate; MiBP, mono-isobutyl phthalate; SRS, Social Responsiveness Scale.