Table 1

Percentage of asthma cases attributable to atopy (defined as at least one positive skin prick test) in population based studies

Reference		Age		Non-asthmatics				Asthmatics		Relative risk	% of cases attributable to atopy	Definition of asthma
Reference		Age		No.	Atopy (%)			No.	Atopy (%)	Relative risk	% of cases attributable to atopy	Definition of asthma
Studies exclusively or predominantly in children
Gergenet al 21	6–17	5505	21		395	45	3.1	30	Diagnosis or frequent wheezing
Burrows et al ⁴	6–34	994	44		89	79	4.8	63	“Asthma” + symptoms
Sears et al 22	13	399	35		315	57	2.5	34	Clinical examination
Norrman et al 23	14	887	40^1-150		110	66	2.5	40	Ever asthma
Von Mutius et al 24	9–11^1-151	4756	37		274	69	3.8	51	Diagnosis with current symptoms
	9–12^1-152	2523	18		100	40	3.0	27	Diagnosis with current symptoms
Martinez et al 25	6	442	35		187	56	2.3	32	Persistent or late onset wheeze
Brooke et al 26	4–9	220	26		54	54	3.3	38	Current wheeze
Sporik et al 27	12–14	53	64		67	73	1.5	25	Respiratory symptoms
Remes and Korppi28	7–12	204	46		43	77	3.8	57	Clinical examination

Studies exclusively or predominantly in adults
Burrowset al ⁴	35–54	498	40		47	72	3.9	53	Asthma with symptoms
	55+	928	23		101	40	2.2	22	Asthma with symptoms
Mensinga et al 29 ^1-153	17–49	2711	26		94	46	2.4	27	Asthma attacks ever
Sparrow et al 30 ^1-154	41–86	598	23		28	29	1.4	8	Adult onset wheeze
Wüthrich et al 31	18–60	7789	21^1-150		568	56	4.8	44	Diagnoses
Settipane et al 32 ^1-154	40–42	654	35		36	56	2.4	32	Asthma attacks
Bodner et al 33	39–45	217	45		102	55	1.5	18	Adult onset wheeze
Siracusa et al 34	0–69	783	19		41	63	7.3	55	Current diagnosed asthma

↵1-150 Estimated.
↵1-151 West Germany.
↵1-152 East Germany.
↵1-153 Atopy definition based on skin prick index (no. of positive reactions × size of weals).
↵1-154 Prospective study, age at end of follow up.
All studies are based on a source population of at least 600 subjects but some prevalence case-control studies involve smaller numbers of cases and controls.