Background The incidence of frailty among the elderly in China increases with age,investigating the mechanisms by which central obesity and vitamin D levels contribute to the development of frailty is essential for effective management strategies.Objective A cross-lagged model was employed to investigate the longitudinal mediating role of vitamin D levels in the relationship between central obesity and frailty among the elderly,thereby offering a theoretical framework for the management of frailty in this population.Methods The study subjects were 1 364 elderly individuals selected from the Chinese Longitudinal Healthy Longevity Study(CLHLS)in 2011-2012(T1)and 2014(T2).The vitamin D levels of the study subjects were measured,and abdominal obesity was assessed using the weight-adjusted-waist index(WWI),while frailty was measured using the frailty index(FI).A cross-lagged model was implemented to analyze the causal temporal relationship and underlying mechanisms between central obesity,vitamin D levels,and frailty among the elderly.Results The detection rate of frailty in the elderly was 21.8%(298/1 364)at T1 and 31.2%(425/1 364)at T2.At two time points,WWI was negatively correlated with vitamin D levels(P<0.05)and positively correlated with FI(P<0.05);vitamin D levels were negatively correlated with FI(P<0.05).Cross-lagged model results showed that WWI at T1 could predict FI at T2(β=1.124,P<0.05),and FI at T1 could predict WWI at T2(β=0.125,P<0.05).Longitudinal mediation effect analysis showed that T1 WWI could not only directly predict T2 FI(β=0.040,P<0.05),but also predict T2 FI through the mediating effect of T2 vitamin D level(β=-0.131,P<0.05).Conclusion Abdominal obesity can not only directly predict frailty in the elderly,but also indirectly affect frailty in the elderly through the longitudinal mediating effect of vitamin D levels.Elderly people should regularly monitor abdominal obesity and vitamin D levels,to prevent or delay the onset of debilitation.
维普
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