Table 1

Allergen levels and prevalence of asthma in cross-sectional studies in children: house dust mite allergen (HDM)

Reference		Age		Allergen level		Non-asthmatics				Asthmatics		OR		Population attributable risk		Definition of asthma
Reference		Age		Allergen level		No.	Exposed			No.	Exposed	OR		Population attributable risk		Definition of asthma
Sporik et al 21		1–15 (asthmatics)	>10 μg/g Der p1		44		70%				82		76%		1.3^1-150		16%	Asthma patients for hospital treatment
Sporik et al 21		10–12 (non-asthmatics)	>10 μg/g Der p1		44		70%				82		76%		1.3^1-150		16%	Asthma patients for hospital treatment
Callet al 22	3–15	⩾10 μg/g HDM grp 1	22	45%		35	26%	0.4^1-150	−39%	Asthma patients for hospital treatment
Verhoeff et al 23	6–12	>2 μg/gDer p1	257	89%		259	83%	0.6^1-150	−55%	Chronic respiratory symptoms
		>10 μg/gDer p1	257	57%		259	54%	0.9^1-150	−6%
Platts Mills et al 24	12–14	>2 μg/g HDM grp 1	47	6%		50	4%	1.4^1-150	1%	Chronic respiratory symptoms
		>10 μg/g HDM grp 1	47	0%		50	0%	–	–	Wheezing
Marks et al 25	8–10	⩾10 μg/gDer p1	35	97%		39	100%	∼1.1^1-150	9%	Wheezing or nocturnal cough; Wheezing, whistling or asthma
Wickenset al 26	7–9	>10 μg/gDer p 1 (living room)	241	79%		233	82%	1.2	16%	Wheezing or nocturnal cough; Wheezing, whistling or asthma
		>10 μg/g Der p 1 (bedroom)	241	83%		233	85%	1.2	20%
		>10 μg/g Der p 1 (bedding)	241	95%		233	90%	0.5	−90%