Table 2 Risk ratios (RRs) between blood lead levels and reported asthma diagnosis by a physician (n = 222)
From: Early life blood lead levels and asthma diagnosis at age 4–6 years
Lead (μg/dL) | Asthma (n = 52) n (%) | No asthma (n = 170) n (%) | RR (95% CI) | aRRa (95% CI) |
|---|---|---|---|---|
Concurrent at 48 months | ||||
< 5 | 19 (37) | 64 (38) | 1.00 | 1.00 |
5–9.9 | 18 (35) | 79 (47) | 0.81 (0.46, 1.44) | 0.66 (0.36, 1.21) |
≥ 10 | 15 (29) | 27 (16) | 1.56 (0.89, 2.75) | 1.14 (0.60, 2.15) |
P for linear trend b | 0.04 | 0.25 | ||
Continuousc | 1.04 (1.00, 1.08) | 1.03 (0.98, 1.09) | ||
Peak at 48 months | ||||
< 5 | 4 (8) | 20 (12) | 1.00 | 1.00 |
5–9.9 | 22 (42) | 78 (46) | 1.32 (0.50, 3.47) | 1.34 (0.44, 4.09) |
≥ 10 | 26 (50) | 72 (42) | 1.59 (0.61, 4.13) | 1.31 (0.43, 3.98) |
P for linear trend | 0.21 | 0.58 | ||
Continuous | 1.02 (0.99, 1.04) | 1.01 (0.98, 1.04) | ||
Lifetime average at 48 months | ||||
< 5 | 15 (29) | 55 (32) | 1.00 | 1.00 |
5–9.9 | 18 (35) | 81 (48) | 0.85 (0.46, 1.57) | 0.81 (0.43, 1.55) |
≥ 10 | 19 (37) | 34 (20) | 1.67 (0.94, 2.97) | 1.30 (0.68, 2.48) |
P for linear trend | 0.15 | 0.52 | ||
Continuous | 1.03 (0.99, 1.08) | 1.02 (0.96, 1.08) | ||
Peak at 24 months | ||||
< 5 | 4 (8) | 28 (17) | 1.00 | 1.00 |
5–9.9 | 23 (44) | 75 (44) | 1.88 (0.70, 5.02) | 2.11 (0.69, 6.42) |
≥ 10 | 25 (48) | 67 (39) | 2.17 (0.82, 5.77) | 2.03 (0.67, 6.16) |
P for linear trend | 0.16 | 0.46 | ||
Continuous | 1.02 (0.99, 1.04) | 1.01 (0.98, 1.05) | ||
Infancy average at 24 months | ||||
< 5 | 18 (35) | 66 (39) | 1.00 | 1.00 |
5–9.9 | 19 (36) | 80 (47) | 0.90 (0.50, 1.59) | 0.89 (0.50, 1.58) |
≥ 10 | 15 (29) | 24 (14) | 1.79 (1.01, 3.17) | 1.42 (0.76, 2.66) |
P for linear trend | 0.25 | 0.73 | ||
Continuous | 1.03 (0.98, 1.08) | 1.01 (0.95, 1.07) | ||