Table 1. Characteristics of studies in the pooled analysis of childhood leukaemia and EMF exposure.

	Subjects			Exposure measurement				Potential confounders
Study	Cases	Controls	Year of diagnosis	Home targeted for assessment	Long-term measurements	Calculated fields	Distance	Sex	Date of birth/age	Dwelling type	Mobility	Socioeconomic status	Urbanisation	Traffic exhaust
Brazil	162	565	2001–2009	Diagnosis	√		√	√	√		√	√
Germany	514	1301	1988–1994	Longest	√			√	√	√	√	√	√
Italy1	119	476	1978–1997	Diagnosis		√	√	√	√			√		√
Italy2	46	184	1986–2007	Diagnosis		√	√	√	√		√	√
Japan	312	603	1999–2001	Diagnosis	√		√	√	√		√	√	√
Tasmania	47	47	1972–1980	Diagnosis			√	√	√		√	√
UK	9695	9695	1962–1995	Birth		√	√	√	√			√	√

Abbreviation: EMF=electronic and magnetic fields.