Participants and interviews

The study is concentrated in the Cantons of Geneva, Vaud, Basel Town, Bern, Zurich and Ticino. Potential participants receive an invitation letter and a brochure on purpose, procedures, and study team. They are informed that we will call them in the following week. If centenarians cannot be reached by phone we contact relatives by phone, letter or visit. If they live in an institution, we contact centenarian’s relatives via the administration. There will be no exclusion criterion, but centenarians or their families may refuse participation.

You wish to be part of this national study? You can contact us through this form or by phone: PHONE NUMBERS

There are different participation levels, based on the cognitive status of the centenarians. If relatives report that cognitive functioning and health of the centenarian is too limited for study participation they may still agree to be enrolled as proxy informants. If relatives refuse participation, they will be asked for basic information to determine sample selectivity (e.g., centenarian’s health, cognitive status, non-participation reasons). If able to provide reliable information, centenarians will be asked whether they approve proxy involvement. Once participation is agreed on, interviews are scheduled within the next two weeks. Due to potential health impairments of the study population, interviews will be conducted at the participant’s residence by well-trained interviewers.

Information about each centenarian will be collected from three sources:

  • the centenarian him/herself (if cognitively able for reliable self-report, see below)
  • the proxy respondent
  • the interviewer

In the first visit, the interviewer explains the study’s nature and objectives to the centenarian in the presence of a next of kin, caregiver, or a facility staff member. In the first visit, the interviewer will explains the study’s nature and objectives to the centenarian in the presence of a next of kin, caregiver, or a facility staff member. They will be able to ask questions. Written informed consent is obtained from participants if considered competent; otherwise, proxy consent is obtained from the next of kin.

Two sessions of 2 hours each (including flexible breaks) are then held in order to collect baseline information. Session 1 includes the assessment for demographics and life achievements, physical health, cognition, quality of life and well-being. Session 2 measures focus on psychopathology and psychological characteristics including personality, psychological strengths, activities, life events, current challenges and goals and attitudes towards death/End of life preparation. Biological indicators are also measured during these sessions, such as blood pressure, temperature, blood samples, etc.

Since the SWISS100 study takes the whole life course into account, information is collected on vulnerability development, such as change in well-being or care transitions. There are then follow-up interviews with the centenarian and the proxy (i.e., one in-person session lasting 1.5 hours) every 6 months. In addition, we will conduct short phone interviews with the proxy (30 minutes) between follow-up sessions (i.e., ca. 3 months after each follow-up).