Table 2.

Method of initial approach to families, by region

Region	Method of approach
North England	Indirect	Telephone	Child's paediatrician phoned; followed by phone call from researcher
West Sweden	Direct	Letter – opt-out	Researcher sent opt-out letter, followed by phone call
Northern Ireland	Indirect	Letter – opt-in	Child's primary notifier to the register sent opt-in letter, follow-up letters and in some cases telephoned some families
South East France	Direct	Letter – opt-out	Researcher sent opt-out letter, followed by phone call
South West Ireland	Direct	Telephone	Researcher phoned, followed by letter
East Denmark	Direct	Letter – opt-out	Researcher sent opt-out letter, followed by phone call
Central Italy	Indirect	Telephone	Doctor, social worker or therapist phoned family, followed by phone call by researcher
South West France	Direct	Telephone	Researcher phoned, followed by letter
North West Germany	Indirect	Face-to-face	Child's primary carer approached family face-to-face