Dynapenic abdominal obesity and elevated risk of multidimensional multimorbidity across physical, psychological, and cognitive domains: evidence from longitudinal cohorts.

BACKGROUND: The long-term impact of dynapenic abdominal obesity (D/AO)-the coexistence of muscle weakness and central adiposity-on physical, psychological, and cognitive multidimensional multimorbidity (mMM) remains unclear.

METHODS: We analyzed longitudinal data from 8,311 adults aged ≥45 [China Health and Retirement Longitudinal Study (CHARLS), n = 4,887; Health and Retirement Study (HRS), n = 3,424] without baseline mMM (i.e., having at most a single-domain impairment), followed biennially for up to 4 years. To account for cross-cultural heterogeneity, analyses were conducted independently per cohort. Three mMM patterns-physical-psychological (PP-MM), physical-cognitive (PC-MM), and physical-psychological-cognitive (PPC-MM)-were constructed using chronic diseases, depressive symptoms, and cognitive tests. Multivariate regression assessed the risk and trajectory of mMM associated with D/AO, and continuous-time Markov multi-state models were utilized to estimate transition probabilities.

RESULTS: In both the CHARLS and HRS cohorts, D/AO was significantly associated with an increased risk of all three specific mMM patterns compared to the non-dynapenic/non-abdominal obesity group, with the strongest association observed for PPC-MM [OR = 2.475 (1.100-5.002) in CHARLS; OR = 5.712 (2.009-14.882) in HRS]. Longitudinal analysis revealed that D/AO was associated with a higher likelihood of entering "incident/worsening" trajectories (RRR = 2.001, P = 0.014 in CHARLS; RRR = 2.507, P = 0.013 in HRS) and an elevated probability of progressing from PC-MM to complex PPC-MM. Notably, age significantly modified these associations, with risk magnitudes markedly higher among individuals aged <65 years (e.g., PP-MM in HRS: OR = 6.98, 95% CI: 1.85-26.31; PC-MM in CHARLS: OR = 4.39, 95% CI: 1.95-9.89). Pooled analyses and multiple sensitivity tests confirmed the robustness of the D/AO "risk gradient effect" across diverse populations, without significant cohort interactions.

CONCLUSION: D/AO is longitudinally associated with a higher incidence of mMM and less favorable health trajectories, particularly among individuals aged <65 years. These findings suggest that integrating muscle strength and abdominal adiposity assessments into primary care may offer potential value for early risk stratification. While the efficacy of targeted interventions warrants further verification in interventional studies, focusing on the D/AO phenotype provides a proactive perspective for mitigating the multidimensional multimorbidity burden in aging populations.