Table 7.  .

Region and author	Year of diagnosis	Disease diagnosis	No. of cases/controls	Exposure measurements	Ages	Results	Reason for exclusion
China, Shanghai: Yang et al (2008)	2006–2007	Acute childhood leukaemia	123/NA	Transformers or power lines within 50 m	0–15	COR=4.39 (95% CI 1.42–13.54) for interaction of XRCC1 Ex9þ16A gene and a residency within 50 m of power line/transformer	Case-only study
Cuba: Perez et al (2005)	1996–2000	Acute childhood leukaemia	NA	SM in each room and outside	0–15	OR=1.2 (median exposure) OR=6.72 (for 0.5 μT) OR=45.15 (for 1 μT)	Methods unclear and problematic
Iran: Feizi and Arabi (2007)	1998–2004	Acute childhood leukaemia	60/59	Distance CF	0–15	Distance: OR=8.76, (95% CI 1.74–58.4) Calculated fields: OR=3.60, (95% CI 1.11–12.4)	Hospital based Problematic magnetic fields calculations
Mexico City: Mejia-Arangure et al (2007)	1995–2003	Acute childhood leukaemia	42/124	SM distance	0–16	OR=4.1 (95% CI 1.05–13) for ⩾0.6 μT vs ⩽0.1 μT)	Included only children with Down's syndrome
Malaysia: Abdul Rahman et al (2008)	2001–2007	Acute childhood leukaemia	128/128	Distance	0–14	OR=2.3 (95% CI 1.18–4.49) for ⩽200 m vs >200 m	Hospital based
Northern Germany: Hoffmann et al (2008)	1986–1998	Leukaemia and lymphoma	97/187	SM in a subset	0–75	NA	Large overlap with study by Schuz (2001), which is included in this pooled analysis
United States, Northern California: Does et al (2009)	2004–2007	Childhood leukaemia	245/269	SM WC	0–8	OR=0.57 (95% CI 0.3–1.93) for >0.3 μT vs <0.1 μT	No long-term measurements in child's bedroom Data not available in time

Abbreviations: CF=calculated fields; CI=confidence interval; COR=case-only odds ratio; NA= not applicable; OR=odds ratio; SM=spot measurements; WC=wire codes; XRCC1=X-ray repair complementing defective repair in Chinese hamster cells 1.