The impact of cognitive impairment and low muscle mass on all-cause mortality among older adults in China: An empirical analysis based on CLHLS cohort data.

The coexistence of cognitive impairment and low muscle mass was associated with the highest risk of all-cause mortality among older adults in China.

• Compared with the CI-/LMM- group, the adjusted HR for the CI+/LMM+ group was 2.54 (95% CI: 2.11–3.05).
• Kaplan-Meier survival analyses and log-rank tests confirmed the CI+/LMM+ group had the highest mortality risk (p < 0.001).
• A total of 5,625 participants from the CLHLS cohort (2011–2018) were included in the analysis.
• The CI+/LMM+ group comprised 791 participants (14.1% of the total sample).

Low muscle mass alone was independently associated with increased all-cause mortality risk compared to participants with neither condition.

• The adjusted HR for the CI-/LMM+ group was 1.29 (95% CI: 1.01–1.51) compared with the CI-/LMM- reference group.
• The CI-/LMM+ group was the largest subgroup, comprising 2,795 participants (49.7% of the sample).
• Cox proportional hazards models were used to estimate hazard ratios after multivariable adjustment.

Cognitive impairment alone was associated with a greater increase in all-cause mortality risk than low muscle mass alone.

• The adjusted HR for the CI+/LMM- group was 1.92 (95% CI: 1.50–2.45) compared with the CI-/LMM- reference group.
• The CI+/LMM- group comprised 341 participants (6.1% of the total sample).
• The reference group (CI-/LMM-) included 1,698 participants (30.2% of the sample).

There was a significant increasing trend in all-cause mortality risk across the four groups defined by cognitive impairment and low muscle mass status.

• Sensitivity analyses confirmed the robustness of the main findings, with a significant increasing trend in mortality risk across the four groups (trend p < 0.001).
• The four groups were: CI-/LMM-, CI-/LMM+, CI+/LMM-, and CI+/LMM+.
• Cox proportional hazards models were applied to estimate HRs and corresponding 95% CIs for all-cause mortality.

The association between coexisting cognitive impairment and low muscle mass with elevated all-cause mortality was particularly pronounced among women and participants aged under 80 years.

• In subgroup analyses, the CI+/LMM+ group was significantly associated with an elevated risk of all-cause mortality among women.
• The CI+/LMM+ group was also significantly associated with elevated mortality risk among participants aged <80 years.
• Subgroup and sensitivity analyses were performed to evaluate the robustness of the findings.

The study sample was drawn from the China Longitudinal Healthy Longevity Survey (CLHLS), a large prospective cohort of older adults.

• Data were collected between 2011 and 2018.
• A total of 5,625 participants were included in the analysis.
• Participants were classified into four mutually exclusive groups based on the presence or absence of cognitive impairment and low muscle mass.
• Kaplan-Meier survival analyses, log-rank tests, and Cox proportional hazards models were used as the primary analytical methods.