At each visit, participants were sent a detailed questionnaire to complete at home; questionnaires were reviewed for completeness during the clinic visit. The questionnaires asked about a variety of health conditions.
In most visits, participants were asked to:
- rate their general health, and their physical and emotional functioning using questions similar to those on the RAND 36-Item Short Form Health Survey (SF-36) developed as part of the Medical Outcomes Study;
- indicate the number of doctor and hospital visits in past year, and reason for hospital visits;
- indicate whether they had ever been told by a doctor that they had any of an extensive list of chronic diseases, including different types of cardiovascular disease, hypertension, pulmonary disease, kidney disease, liver disease, thyroid disease, osteoporosis, and different types of cancer. In some cases, participants were also asked to indicate age at first diagnosis.