For the purposes of the present part of the Atahualpa Project, field personnel were trained to achieve expertise with the use of the screening questionnaires, and to assure uniformity in data collection. The independent review board of Hospital-Clínica Kennedy (Guayaquil, Ecuador) approved the study design and the informed consent form that has to be signed by all Atahualpa residents aged ≥40 years before enrollment in the study.