Fig. 2

Estimated trajectories of the FI over 7 years by CRP groups using a linear mixed model. Y axis represented the predicted frailty index based on a model adjusted for age, sex, education level, marital status, smoking status, drinking status, residence, and body mass index by CRP quartiles. Different CRP groups were represented using type of lines. represented the group Q4 (the highest CRP group), represented Q3, represented Q2, represented Q1(the lowest CRP group). Participants in the Q4 group had the fastest rate of rise of FI over time, with the Q1 group being the slowest. *P < 0.05, **P < 0.01