subsample studies of interest include the Finnish Twin Study of Ageing (FITSA, https://www.jyu.fi/sport/laitokset/tutkimusyksikot/sgt/en/Research/fitsa) of elderly female twins. The TwinSpine study has assessed disc degeneration and back disorders among 600 male twins using MRI assessments across three waves in the past 15 years. This study has won numerous awards, including the American Academy of Orthopaedic Surgeons’ 2008 Kappa Delta Elizabeth Winston Lanier Award (Battie et al, 2009).
