Table 2

Controlled trials of allergen avoidance achieving a prolonged decrease in mite allergen

*Authors*	*Trial duration*	*Intervention*	n	*Decrease in mite allergen*	*Primary outcome*
Murray & Ferguson57	1 year	Physical barriers	10/10	++	BHR^2-160
Carswell et al 68	6 months	Physical barriers, acaricide, washing, vacuuming	24/25	+	PEFR^2-151/BHR^2-151
Ehnertet al 37	1 year	Physical barriers	8/16	++	BHR^2-160
Walshaw & Evans69	1 year	Physical barriers	22/20	++	PEFR^2-160/BHR^2-160
Van der Heide et al 70	6 months	Physical barriers, air cleaaners	15/15/15	++	BHR^2-150
Htut et al 63	6–12 months	Hot air, ventilation, steam cleaning	7/8/8	++	BHR^2-150

Improvement:
↵2-160 highly significant,
↵2-150 significant,
↵2-151 not significant. PEFR = peak expiratory flow rate; BHR = bronchial hyperresponsiveness.