Table 3.

Random effects Pooled Odds Ratios (ORs) and 95% confidence intervals (CIs) of allergic rhinitis and asthma in different subgroups.

Groups	Number of studies	OR (95% CI)	Ria	p- value of Q test
All studies	29	3.82 (2.92–4.99)	0.98	<0.001
Design
Cohort studies	22	3.42 (2.60–4.50)	0.96	<0.001
Case-control studies	7	4.71 (3.58–6.17)	0.70	0.003
Region
European	21	4.35 (3.12–6.06)	0.98	<0.001
Non European	8	2.75 (2.16–3.50)	0.73	<0.001
Age group
Children	15	4.10 (2.56–6.56)	0.99	<0.001
Adults	14	3.37 (2.64–4.30)	0.89	<0.001
Quality Score
<3	11	3.86 (2.49–6.00)	0.99	<0.001
≥3	18	3.61 (2.97–4.39)	0.51	0.006
Items of quality assessment:
Proper definition of target population
Yes	23	3.42 (2.62–4.48)	0.96	<0.001
No	6	6.26 (3.18–12.30)	0.97	<0.001
Proper diagnosis of asthma
Yes	9	3.67 (2.52–5.34)	0.81	<0.001
No	20	3.82 (2.92–4.99)	0.98	<0.001
Proper diagnosis of Allergic Rhinitis
Yes	12	5.06 (3.58–7.15)	0.64	0.001
No	17	3.18 (2.26–4.46)	0.99	<0.001
Clear temporal trend between rhinitis and occurrence of asthma
Yes	24	3.55 (2.74–4.61)	0.96	<0.001
No	5	4.89 (3.26–7.35)	0.68	0.015
Adjustment
Full adjustment	12	3.82 (2.92–4.98)	0.43	0.057
Incomplete adjustment	17	3.94 (2.77–5.61)	0.99	<0.001

^aProportion of total variance due to between-study variance