Information on the type and number of medications taken regularly has been obtained from reports made at five home visits at age 36, 43, 53, 60-64 and 68-70, and from the responses to postal questionnaires at 31 and 60-64 years. Respondents were usually asked if they 'regularly took any medicines, pills or tablets (or have regular injections)?' and asked to complete questions on the reason, duration, name and dosage of any medications taken.

The 2006-10 data collection was slightly different, in that study members were asked two sets of medication questions. The postal questionnaire asked the usual question about regular taking of medications, whereas the home visit asked for details of medications taken in the past 24 hours.