Table 3. Atopy among schoolchildren enrolled in an asthma case-control between 2015–17 (N = 1,635).
| Atopy characteristics | Asthma cases N = 546 |
Non-asthma controls N = 1089 |
Adj. OR (95% CI)‡ |
|---|---|---|---|
| Any positive skin prick test to any of 7 allergens | |||
| Yes (653) | 302 (55.3) | 351 (32.2) | 2.40 (1.92–3.00) |
| Blomia tropicalis (dust mite) SPT | |||
| Positive (478) | 241 (44.1) | 237 (21.8) | 2.51 (1.98–3.19) |
| Dermatophagoides mix (dust mite) SPT | |||
| Positive (535) | 262 (48.0) | 273 (25.1) | 2.46 (1.95–3.10) |
| German cockroach SPT | |||
| Positive (354) | 150 (27.5) | 204 (18.7) | 1.59 (1.23–2.06) |
| Peanut SPT [m = 4] | |||
| Positive (57) | 27 (5.0) | 30 (2.8) | 1.73 (0.99–3.05) |
| Cat SPT | |||
| Positive (22) | 22 (4.0) | 23 (2.1) | 1.94 (1.02–3.69) |
| Pollen mix (weeds) SPT [m = 2] | |||
| Positive (43) | 22 (4.0) | 21 (1.9) | 2.14 (1.11–4.11) |
| Mould mix SPT | |||
| Positive (19) | 8 (1.5) | 11 (1.0) | 1.40 (0.52–3.76) |
| Fractional exhaled nitric oxide (FENO) [m = 42] | |||
| Elevated (>35 ppb) (378) | 199 (36.7) | 179 (17.0) | 2.57 (2.01–3.29) |
| Any positive allergen-specific IgE¥ (of 3 allergens, N = 392) | |||
| Atopic level (249) | 143 (72.6) | 106 (54.4) | 2.45 (1.53–3.91) |
| Dermatophagoides-IgE | |||
| Atopic level (186) | 116 (58.6) | 70 (35.9) | 2.32 (1.49–3.63) |
| Cockroach IgE | |||
| Atopic level (198) | 110 (55.8) | 88 (45.1) | 1.69 (1.08–2.63) |
| Peanut IgE | |||
| Atopic level (63) | 39 (19.7) | 24 (12.3) | 1.92 (1.05–3.50) |
| Total IgE: Mean (SD) kU/L | 930.25 (1246.60) | 640.88 (1146.61) | 1.00024 (1.00005–1.00043) |
N = number; Adj. OR = adjusted odds ratio; CI = confidence interval; SD = standard deviation; m = missing; ppb = parts per billion; number (%) shown in 2nd and 3rd column unless indicated otherwise.
*adjusted for child’s age, sex, residence at birth and father’s education level. Skin prick test using whole allergen extracts.
¥allergen-specific IgE levels were obtained using ImmunoCAP, on a random sample of 200 cases and 200 controls; standard cut-off for allergic sensitisation (>0.35 allergen-specific kilo units per litre (kUA/L)).