From: Early life blood lead levels and asthma diagnosis at age 4–6 years
Characteristics | Study sample n = 222 n (%) | Lifetime average blood lead levels (μg/dL) | Asthma diagnosis n = 52 n (%) | ||
< 5 n = 70 n (%) | 5–9.9 n = 99 n (%) | ≥ 10 n = 53 n (%) | |||
Child sex | |||||
Male | 113 (51) | 30 (43) | 47 (47) | 36 (68) | 34 (65) |
Female | 109 (49) | 40 (57) | 52 (53) | 17 (32) | 18 (35) |
Birthweight (grams) | |||||
< 2500 | 15 (7) | 6 (9) | 7 (7) | 2 (4) | 3 (6) |
2500–4000 (normal) | 195 (88) | 57 (81) | 89 (90) | 49 (92) | 46 (88) |
≥ 4000 | 12 (5) | 7 (10) | 3 (3) | 2 (4) | 3 (6) |
Median | 3270 | 3326 | 3203 | 3270 | 3326 |
(IQR) | (2891–3570) | (2850–3620) | (2850–3620) | (2976–3570) | (2990–3662) |
Maternal race | |||||
White | 59 (27) | 33 (47) | 21 (21) | 5 (9) | 12 (23) |
Non-white | 163 (73) | 37 (53) | 78 (79) | 48 (91) | 40 (77) |
Maternal age at birth (years) | |||||
<20 | 68 (31) | 19 (27) | 33 (33) | 16 (30) | 13 (25) |
20-24 | 45 (20) | 12 (17) | 21 (21) | 12 (23) | 14 (27) |
25–30 | 61 (27) | 21 (30) | 23 (23) | 17 (32) | 16 (31) |
≥ 30 | 48 (22) | 18 (26) | 22 (22) | 8 (15) | 9 (17) |
Median (IQR) | 24.6 (19.1–29.3) | 26.1 (19.6–30.7) | 23.6 (19.3–29.8) | 23.9 (18.4–27.5) | 24.2 (20.2–29.0) |
Maternal education | |||||
Less than high school | 61 (27) | 12 (17) | 28 (28) | 21 (40) | 16 (31) |
High school/GED | 77 (35) | 24 (34) | 33 (33) | 20 (38) | 20 (38) |
More than high school | 84 (38) | 34 (49) | 38 (38) | 12 (22) | 16 (31) |
Maternal parity at 72 months of age | |||||
0 | 79 (36) | 33 (47) | 33 (33) | 13 (25) | 18 (35) |
1 | 56 (25) | 17 (24) | 25 (25) | 14 (26) | 13 (25) |
2 | 40 (18) | 10 (14) | 20 (20) | 10 (19) | 6 (12) |
3 | 30 (14) | 9 (13) | 13 (13) | 8 (15) | 8(15) |
≥ 4 | 17 (8) | 1 (2) | 8 (8) | 8 (15) | 7 (13) |
Annual household income at 72 months of age | |||||
< 24,999 | 155 (70) | 34 (49) | 74 (76) | 47 (90) | 41 (79) |
≥ 25,000 | 65 (30) | 36 (51) | 24 (24) | 5 (10) | 11 (21) |
Household smoking exposure at 72 months of age | |||||
No | 116 (52) | 45 (64) | 45 (45) | 26 (49) | 25 (48) |
Yes | 106 (48) | 25 (36) | 54 (55) | 27 (51) | 27 (52) |
Child ever breastfed by 6 months of age | |||||
No | 184 (83) | 55 (79) | 82 (83) | 47 (89) | 49 (94) |
Yes | 38 (17) | 15 (21) | 17 (17) | 6 (11) | 3 (6) |
Daycare attendance at 72 months of age | |||||
No | 140 (63) | 47 (67) | 57 (58) | 36 (68) | 34 (65) |
Yes | 82 (37) | 23 (33) | 42 (42) | 17 (32) | 18 (35) |