Methods and results
A prospective cohort study, reported usual FTR levels at baseline in 2005–2015 and the participants of MVR have been followed up for 5~6 years, approximately every one years, and so far, the data have been collected across five subsequent phases. Five-year longitudinal trajectories of FTR were identified using group-based trajectory modelling(GBTM). We identified 3 distinct trajectories using a GBTM, labeled by initial value and changing pattern: stable group(258/378, 68.2%), increasing-slow group(67/378, 17.6%) and increasing-fast group(53/378, 14.2%). Treating the stable group as the reference, the age- and sex-adjusted odds ratio(OR) was 25.84 (95% confidence interval, 11.78-56.65) for the increasing-slow group and 139.94(95% confidence interval, 45.47-430.68) for the increasing-fast group by logistic regression model. After adjustment for every potential confounding factors, the OR is 14.21(95% confidence interval, 4.36-46.33)、49.34(95% confidence interval, 8.88-273.87) respectively.