TABLE I.
Distribution of covariates across IPT exposure categories over the mother’s life course (n = 478)
| All, n = 478 | Periods of IPT | P value* | ||||
|---|---|---|---|---|---|---|
| No IPT, n = 285 (60%) |
Early-life IPT, n = 107 (22%) |
Late-life IPT, n = 29 (6%) |
Chronic IPT, n = 57 (12%) |
|||
| Maternal age (y), mean ± SD | 26.6 ± 5.7 | 26.4 ± 5.6 | 26.1 ± 6.0 | 27.2 ± 4.9 | 27.7 ± 6.1 | .31 |
| Maternal race, no. (%) | .001 | |||||
| Hispanic | 282 (59%) | 188 (66%) | 49 (46%) | 17 (58%) | 28 (49%) | |
| Black | 141 (30%) | 73 (26%) | 44 (41%) | 6 (21%) | 18 (32%) | |
| White | 20 (4%) | 7 (2%) | 7 (6.5%) | 2 (7%) | 4 (7%) | |
| Other/mixed | 35 (7%) | 17 (6%) | 7 (6.5%) | 4 (14%) | 7 (12%) | |
| Maternal education, no. (%) | .66 | |||||
| < High school | 165 (35%) | 101 (35%) | 37 (34%) | 10 (34%) | 17 (30%) | |
| High school degree | 140 (29%) | 80 (28%) | 34 (32%) | 6 (21%) | 20 (35%) | |
| ≥ Some college | 144 (30%) | 84 (30%) | 31 (29%) | 13 (45%) | 16 (28%) | |
| Missing | 29 (6%) | 20 (7%) | 5 (5%) | 0 (0%) | 4 (7%) | |
| Current economic difficulties, mean ± SD | 5.7 ± 2.5 | 5.4 ± 2.3 | 5.8 ± 2.6 | 6.4 ± 2.8 | 6.7 ± 2.7 | .002 |
| Prenatal smoking, no. (%) | .12 | |||||
| Prenatal smoking | 60 (13%) | 32 (11%) | 12 (11%) | 3 (10%) | 13 (23%) | |
| No smoking | 407 (85%) | 244 (86%) | 93 (87%) | 26 (90%) | 44 (77%) | |
| Missing | 11 (2%) | 9 (3%) | 2 (2%) | 0 (0%) | 0 (0%) | |
| Maternal atopy, no. (%) | .04 | |||||
| Atopy | 170 (36%) | 88 (31%) | 42 (39%) | 12 (41%) | 28 (49%) | |
| No atopy | 308 (64%) | 197 (69%) | 65 (61%) | 17 (59%) | 29 (51%) | |
| Parental home ownership, no. (%) | .25 | |||||
| Parents owned home | 248 (52%) | 152 (53%) | 51 (47%) | 16 (55%) | 29 (51%) | |
| Parents did not own home | 175 (37%) | 94 (33%) | 50 (47%) | 9 (31%) | 22 (38.5%) | |
| Missing | 55 (11%) | 39 (14%) | 6 (6%) | 4 (14%) | 6 (10.5%) | |
| Child’s sex, no. (%) | .75 | |||||
| Male | 250 (52%) | 147 (52%) | 58 (54%) | 13 (45%) | 32 (56%) | |
| Female | 228 (48%) | 138 (48%) | 49 (46%) | 16 (55%) | 25 (44%) | |
| Birth weight, z value for gestational age, mean ± SD | −0.4 ± 0.2 | −0.5 ± 1.2 | −0.3 ± 1.3 | −0.3 ± 1.1 | −0.5 ± 1.2 | .75 |
| Season of birth, no. (%) | .82 | |||||
| Winter | 135 (28%) | 78 (27%) | 36 (34%) | 7 (24%) | 14 (25%) | |
| Summer | 100 (21%) | 62 (22%) | 20 (19%) | 7 (24%) | 11 (19%) | |
| Spring | 117 (25%) | 67 (24%) | 25 (23%) | 6 (21%) | 19 (33%) | |
| Fall | 126 (26%) | 78 (27%) | 26 (24%) | 9 (31%) | 13 (23%) | |
| Other current NLEs,† mean ± SD | 2.3 ± 2.8 | 1.7 ± 2.3 | 2.8 ± 2.7 | 2.1 ± 2.4 | 4.2 ± 3.9 | .001 |
| Detectable dust mite‡ in home, no. (%) | .74 | |||||
| Dust mite | 345 (73%) | 71 (25%) | 24 (23%) | 10 (35%) | 17 (30%) | |
| No dust mite | 88 (18%) | 184 (65%) | 71 (66%) | 19 (65%) | 37 (65%) | |
| Missing dust mite | 45 (9%) | 30 (10%) | 12 (11%) | 0 (0%) | 3 (5%) | |
| Detectable cockroach§ in home, no. (%) | .08 | |||||
| Cockroach | 122 (26%) | 194 (68%) | 83 (78%) | 22 (76%) | 46 (81%) | |
| No cockroach | 311 (65%) | 61 (21%) | 12 (11%) | 7 (24%) | 8 (14%) | |
| Missing cockroach | 45 (9%) | 30 (11%) | 12 (11%) | 0 (0%) | 3 (5%) | |
*
For differences between nonmissing multigroup comparisons using ANOVA and χ2 distribution.
†
Current NLEs other than IPT.
‡
Detectable levels for dust mites (Der f 1 and Der p 1, >0.02 µg/g).
§
Detectable levels for cockroach allergens (Bla g 1, >0.40 U/g; Bla g 2, >1.0 U/g).