Associations of serum total light chain kappa and lambda levels with all-cause mortality in Chinese centenarians.

The purpose of this study was to determine the relationship between the serum levels of kappa (κ) and lambda (λ) total light chain (TLC), the κ/λ ratio, and the combined serum TLCκ and TLCλ (ΣTLC) levels in Chinese centenarians and all-cause mortality. The association between serum TLC and all-cause mortality was investigated using restricted cubic spline (RCS) analysis, Cox proportional hazards models, and Kaplan‒Meier curves. The study included 906 centenarians (18.8% male), 838 (92.5%) of whom died during a median follow-up of 30 months. The proportions of centenarians with abnormal TLCκ and TLCλ levels were 68.1% and 49.0%, respectively. RCS analysis indicated that the levels of TLCκ, TLCλ, and ΣTLC were associated with all-cause mortality (P < 0.05), whereas the κ/λ ratio was not (P > 0.05). Cox proportional hazards analysis demonstrated that the highest quartiles of TLCκ, TLCλ, and ΣTLC were associated with an increased risk of death, with hazard ratios of 1.434 (95% confidence interval [CI], 1.061-1.939; P = 0.019), 1.351 (95% CI, 1.013-1.802; P = 0.041), and 1.891 (95% CI, 1.347-2.654; P < 0.001), respectively. Kaplan-Meier analysis illustrated that centenarians with higher levels of TLCκ, TLCλ, and ΣTLC had significantly shorter median survival times (26 months versus 35 months, P < 0.001; 26 months versus 32 months, P = 0.003; and 26 months versus 36 months, P < 0.001, respectively). Our findings suggest that serum levels of TLCκ, TLCλ, and ΣTLC are significantly associated with all-cause mortality in centenarians. Trial registration Not applicable.