Ongoing ALSPAC clinic based data collection is impractical and not cost-effective. Alternative methods of ensuring and extending follow-up are required. Efficient and effective follow-up of the health status (and some other factors) of ALSPAC can be achieved through record linkage. 90% of health service contacts occur in primary care and primary care information systems record all significant clinical diagnoses and events throughout the life course such as hospital visits and admissions and data quality is improving. Projects based on "e health" supported by MRC and NIH are being developed in order to facilitate recruitment and follow-up of patients through primary care information systems (see http://www.pcpoh.bham.ac.uk/ primarycare/mdm/e-health.htm).

Information systems also are being developed regionally to enable Primary Care Trusts and Strategic Health Authorities to communicate and retrieve data from general practice information systems. Avon Information Management and Technology (Avon IMT), based in Bristol (http://nww.avon.nhs.uk/imtconsortium/Information_Services), administers the Exeter system which records details on all patients registered with GPs in Avon, has linked the Exeter system with Hospital Episode Statistics, and is commissioning a new information system to allow remote data retrieval from GP systems. The flagging and record linkage between ALSPAC and Avon Exeter systems is achievable - time and permission allowing. Confidentiality and data security are critical to the development of these new information systems linking and extracting data from primary care. Informed consent is required to allow access to the systems, and to allow ALSPAC to periodically update and follow-up health status of its cohort.