Equipment costs were discounted at 5%. Costs and quantities were not reported separately. Costs to health care, screening organisation and patients were considered, including screening costs (including follow up telephone calls), medical care costs (physician visits, laboratory tests etc) and participant (employer and employee) costs (e.g., for follow up, travel etc). The estimation of the costs was based on actual data (the units of analysis). Data were collected from participants' year-end assessment and medical records. Prices related to 1987.