RT Journal Article SR Electronic T1 Importance of population-based longitudinal studies to understanding the impact of COVID-19 JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP jech-2021-217114 DO 10.1136/jech-2021-217114 A1 Panayotes Demakakos YR 2021 UL http://jech.bmj.com/content/early/2021/05/23/jech-2021-217114.abstract AB