Table 1.
Select characteristics and results of 14 studies of day-care attendance and risk of childhood leukaemia.
| Study | Country | Outcome, agea | Exposure |
|||
|---|---|---|---|---|---|---|
| Definition | Timing | No. of cases | OR (95% CI) | |||
| Petridou et al.(20) | Greece | Leukaemia, 0–14 | Attendance at creche: yes/no | Before age 2 | 136 | 0.28 (0.09–0.88) |
| Roman et al.(22) | UK | ALL, 0–4 | Pre-school playgroup: yes/no | Year before diagnosis | 38 | 0.60 (0.20–1.80) |
| Petridou et al.(21) | Greece | Leukaemia, 0–14 | Day-care: ever/never | Birth to diagnosis | 153 | 0.83 (0.51–1.37) |
| Schuz et al.(24)b | Germany | AL, 1.5–14 | Deficit in social contacts: no/yes | Before age 2 | 921 | 0.91 (0.90–1.30) |
| Dockerty et al.(13) | New Zealand | ALL, 1.25–14 | Regular contact outside home: yes/no | First year of life | 90 | 0.65 (0.36–1.17) |
| Infante-Rivard et al.(15) | Canada | ALL, 0–9 | Day-care: entry at ≤2 y/never | At or before age 2 | 490 | 0.49 (0.31–0.77) |
| Rosenbaum et al.(23)b | USA | ALL, 0–14 | Out of home care: >36 months./none | Birth to diagnosis | 248 | 0.76 (0.70–2.52) |
| Neglia et al.(18) | USA | ALL, 1–14 | Day-care before age 2: yes/no | Before age 2 | 1744 | 0.99 (0.84–1.17) |
| Chan et al.(12) | Hong Kong | AL, 2–14 | Index and family day-care: 3-level | First year of life | 98 | 0.96 (0.70–1.32) |
| Perrillat et al.(19) | France | AL, 2–15 | Day-care attendance: yes/no | Birth to diagnosis | 246 | 0.60 (0.40–1.00) |
| Jourdan-Da Silva et al.(16) | France | ALL, 1–14 | Day-care attendance: yes/no | Birth to diagnosis | 387 | 0.70 (0.60–1.00) |
| Gilham et al.(14) | UK | ALL, 2–14 | Social activity: any/none | First year of life | 1272 | 0.66 (0.56–0.77) |
| Ma et al.(10)(White) | USA | ALL, 1–14 | Child-hours of exposure: ≥15 000/0 | Birth to diagnosis | 136 | 0.60 (0.28–1.27) |
| Ma et al., (10)(Hispanic) | USA | ALL, 1–14 | Child-hours of exposure: ≥15 000/0 | Birth to diagnosis | 120 | 1.27 (0.62–2.56) |
| Kamper-Jorgensen et al.(17) | Denmark | ALL, 0–15 | Attendance to childcare: yes/no | Before age 2 | 176 | 0.68 (0.48–0.95) |
aALL, acute lymphoblastic leukaemia; AL, acute leukaemia; age ranges are for those included in the analysis.
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’.