Table 3: Relationship among asthma morbidity, dust allergen sensitivity, and dust allergen concentration.

OutcomeaConcentrationbSensitivitycAllergen
CockroachP Dust miteP MouseP Alternaria P

N Above medianPositive17372951
Negative19255137
Below medianPositive75832545
Negative68347446

Maximum symptom daysAbove medianPositive8.247.387.147.820.16
Negative6.420.376.800.446.330.566.78
Below medianPositive6.896.725.605.71
Negative6.035.537.016.13

Daytime symptomsAbove medianPositive5.825.895.346.35
Negative5.420.985.400.575.220.965.220.34
Below medianPositive5.375.555.164.80
Negative5.294.445.615.04

Night symptomsAbove medianPositive2.943.624.864.25
Negative2.790.332.480.513.060.192.300.18
Below medianPositive3.993.643.003.11
Negative2.782.742.963.24

Slow playAbove medianPositive6.183.814.343.84
Negative2.890.012.880.392.630.162.920.54
Below medianPositive3.133.342.282.98
Negative2.542.293.392.83

Caretaker changed plansAbove medianPositive1.530.811.341.12
Negative0.950.330.800.970.980.210.430.27
Below medianPositive0.710.950.401.00
Negative0.930.910.820.91

aOutcome units are “number of days in the past 2 weeks.” P values test for an interaction between allergen sensitivity and concentration for the given outcome.
bMedian concentrations: cockroach—0.2 U/g (lower limit of detection), dust mite—0.1 μg/g (LLOD), mouse—0.03 μg/g (LLOD), Alternaria—13.7 μg/g (LLOD).
cSkin test wheal was at least 3 mm greater than the negative control; allergen sensitivity corresponds to dust allergen exposure (e.g., cockroach allergen sensitivity and concentration).