Table 3.

Causal mediation analysis of age, body mass index, and waist circumference as potential mediators on the effect of health-related quality of life on the risk of sarcopenia

Mediators		Euro-QoL-Five Dimensions-three levels index score
		Estimatea	95% CI	P value
Age	Total effectb	− 0.73	− 1.02 to − 0.44	<0.001
	Direct effectc	− 0.53	− 0.80 to − 0.25	<0.001
	Indirect effectd	− 0.21	− 0.30 to − 0.11	<0.001
Body mass index	Total effectb	− 0.53	− 0.80 to − 0.25	<0.001
	Direct effectc	− 0.59	− 0.85 to − 0.33	<0.001
	Indirect effectd	0.06	− 0.02 to 0.14	0.129
Waist circumference	Total effectb	− 0.53	− 0.80 to − 0.25	<0.001
	Direct effectc	− 0.57	− 0.83 to − 0.30	<0.001
	Indirect effectd	0.04	− 0.03 to 0.10	0.231

Results based on covariate-adjusted causal mediation analyses. Analysis was adjusted for sex, educational attainment, hypertension, diabetes, marriage status, and residency status. Estimates were calculated taking the non-sarcopenia group as reference

CI, Confidence Interval

^aBootstrapped β coefficients. Negative estimates indicate that age, body mass index, and waist circumference are associated with the risk of sarcopenia

^bEffect of health-related quality of life on the risk of sarcopenia includes the mediator’s (age, body mass index, or waist circumference) effect

^cEffect of health-related quality of life on the risk of sarcopenia excludes the mediator’s (age, body mass index, or waist circumference) effect

^dEffect of health-related quality of life on the risk of sarcopenia through the mediators (age, body mass index, or waist circumference)