Association Between the Frailty Index and Self-Reported Headache in Middle-Aged and Older Chinese Adults: An Analysis of the China Health and Retirement Longitudinal Study.

BACKGROUND

Headache is one of the common subjective discomfort symptoms in middle-aged and elderly people, which seriously affects the quality of life. Frailty is a syndrome characterizing the aging state, but the association between frailty and headache lacks support from large-sample studies.

METHODS

This cross-sectional analysis used data from the China Health and Retirement Longitudinal Study (CHARLS). We concatenated the 2011/2013/2015 waves and used cluster-robust standard errors at the participant level to account for repeated measures; all analyses applied CHARLS sampling weights. A 35-item index was used to construct the frailty index (FI) and grouped by quartiles. The association between frailty and headache was assessed using multifactorial logistic regression models, and nonlinear associations were assessed using restricted cubic spline (RCS) analysis. Robustness tests included subgroup analyses and interaction tests.

RESULTS

A total of 28,402 participants were included. Multivariable logistic regression showed that FI was positively associated with headache. In the fully adjusted model, each 0.1-point increase in FI was associated with a 13.5% higher odds of headache (OR = 1.135, 95% CI: 1.130-1.139, p < 0.001). Compared with Q1, participants in Q2, Q3, and Q4 had progressively higher odds of headache, with the highest odds observed in Q4 (P for trend < 0.001). RCS analysis indicated a significant nonlinear positive association between FI and headache (P for nonlinearity < 0.001), with a more pronounced increase in headache odds at higher FI levels. Subgroup analyses were generally consistent, with nominal interactions observed by drinking status and hypertension.

CONCLUSION

Higher frailty levels were associated with greater headache odds with a nonlinear pattern. Given the cross-sectional design, temporality and causality cannot be established, and future longitudinal studies are needed to clarify causal relationships.