Cohort Profile: The Lausanne cohort 65+ (Lc65+)

Why was the cohort set up?The proportion of the population over the age of 65 years has doubled from 1950 to nowadays in Switzerland 1 as everywhere else in the world, 2 and will continue to increase until 2030 when the youngest Baby Boomers turn 65.This demographic shift represents a major challenge to society in general and to the health care system in particular, but it also brings potential opportunities, thanks to Key Features• The Lc65þ study is a population-based longitudinal study with a cohort-sequential design.It aims to gain new knowledge of the determinants, the development and the consequences of age-related frailty from its initial manifestations in the youngest old.• Three representative samples of the non-institutionalized population of Lausanne (Switzerland) aged 65 to 70 years were recruited at 5-year intervals in 2004 (birth year 1934-1938, N ¼ 1564), 2009 (birth year 1939-1943, N ¼ 1489) and 2014 (birth year 1944-1948, N ¼ 1678).Follow-up combined annual postal questionnaires as well as in-person interviews and examinations planned every third year at the study centre.The response rate has remained above 90% over the years, with 779 (50%) of the initial respondents in 2004 still participating 16 years later.• Postal questionnaires address a large set of both objective and subjective measures, including life history, physical and mental health, socioeconomic status, health services use and health behaviours.Ad hoc surveys have been conducted on topics such as falls, quality of life and COVID-19.In-person interviews and examinations include a set of anthropometric and cardiovascular indices, as well as physical and cognitive performance tests.