. 2010 Feb 23;39(3):718–732. doi: 10.1093/ije/dyp378

Table 3.

Subgroup meta-analyses of day-care attendance and risk of childhood ALL evaluating the influence of timing of day-care attendance

Study, year	Day care any time				Day care at age ≤ 2
Study, year		Cases	OR	95% CI	Wi (%)^a	Cases	OR	95% CI	Wi (%)^a
Petridou et al., 1993²³	136	0.67	0.41, 1.11	7.7	136	0.28	0.09, 0.88	2.3
Roman et al., 1994⁴⁰
Petridou et al., 1997²⁴	153	0.83	0.51, 1.37	7.8
Schuz et al., 1999^42,^b					921	0.91	0.90, 1.30	15.7
Dockerty et al., 1999²²					90	0.65	0.36, 1.17	6.5
Infante-Rivard et al., 2000³⁴					433	0.49	0.31, 0.77	8.8
Neglia et al., 2000³⁸	1744	0.96	0.82, 1.12	38.0	1744	0.99	0.84, 1.17	16.1
Rosenbaum et al., 2000^41,^b	158	0.76	0.70, 2.52	4.9
Chan et al., 2002³²					98	0.96	0.70, 1.32	12.0
Perrillat et al., 2002³⁹	246	0.60	0.40, 1.00	8.9
Jourdan-Da Silva et al., 2004³⁵	387	0.70	0.60, 1.00	22.1
Gilham et al., 2005³³					1272	0.66	0.56, 0.77	28.8
Ma et al., 2005—White³⁷	136	0.75	0.38, 1.45	4.5	136	0.77	0.43, 1.40	2.1
—Hispanic³⁷	120	1.09	0.62, 1.90	6.2	120	1.92	0.89, 4.13	1.2
Kamper-Jorgensen et al., 2008³⁶					176	0.68	0.48, 0.95	6.3
Combined:	3080	0.81	0.70, 0.94	100.0	5126	0.79	0.65, 0.95	100.0
P-value (heterogeneity):	0.277				0.001

^aPercent weight assigned to each OR in the random effects model. Wi, weight.

^bSchuz et al.: changed reference to ‘Yes-deficit in social contacts’ by calculating the inverse of the OR provided for ‘No-deficit in social contacts’; Rosenbaum et al.: estimated the OR for ‘ > 36 months’ by calculating the inverse of the originally provided OR for ‘stayed home’.