Table 3.

Association between muscle quality index and mortality

	Quintiles of Muscle Quality Index, Watts (W)
	Quintile 1	Quintile 2	Quintile 3	Quintile 4	Quintile 5	Ptrend
Full Sample (N=4,510)
Median [IQR] (watts)	57.3 [49.0–65.0]	82.8 [76.8–88.7]	105.4 [99.0–112.6]	135.5 [126.5–144.9]	186.1 [168.0–212.2]
Median [IQR] Survival, Yrs.	10.7 [6.25–18.8]	13.4 [7.7–21.5]	15.0 [8.7–21.9]	15.9 [9.1–21.5]	16.8 [9.8–22.7]	<0.001
Model 1*	1.92 (1.58–2.35)	1.46 (1.21–1.75)	1.27 (1.07–1.51)	1.19 (1.01–1.39)	1.00 – Ref	<0.001
Model 2†	1.90 (1.53–2.36)	1.65 (1.36–1.98)	1.47 (1.24–1.75)	1.23 (1.05–1.44)	1.00 – Ref	<0.001
Model 3‡	1.57 (1.23–2.01)	1.43 (1.16–1.75)	1.23 (1.02–1.48)	1.09 (0.92–1.30)	1.00 – Ref	<0.001
Model 4§	1.55 (1.20–1.99)	1.43 (1.16–1.76)	1.22 (1.01–1.47)	1.13 (0.95–1.34)	1.00 – Ref	<0.001
Model 5||	1.50 (1.15–1.96)	1.39 (1.11–1.73)	1.21 (0.99–1.47)	1.13 (0.95–1.34)	1.00 – Ref	0.001
Males Only (N=2,240)
Median [IQR] (watts)	81.4 [71.1–89.6]	109.7 [102.9–115.	131.5 [125.2–138.2]	160.2 [151.9–170.0]	208.7 [192.6–251.7]
Median [IQR] Survival, Yrs.	9.7 [4.1–15.0]	9.7 [4.7–16.6]	12.0 [7.0–19.0]	16.2 [8.7–NR]	16.7 [10.3–22.7]	<0.001
Model 1*	2.27 (1.72–3.01)	2.07 (1.59–2.69)	1.62 (1.27–2.07)	1.12 (0.90–1.40)	1.00 – Ref	<0.001
Model 2†	1.81 (1.39–2.37)	1.73 (1.36–2.21)	1.32 (1.04–1.68)	1.05 (0.85–1.30)	1.00 – Ref	<0.001
Model 3‡	1.42 (1.05–1.90)	1.46 (1.15–1.87)	1.14 (0.88–1.47)	0.92 (0.73–1.15)	1.00 – Ref	<0.001
Model 4§	1.44 (1.06–1.95)	1.47 (1.15–1.89)	1.20 (0.93–1.54)	0.91 (0.72–1.14)	1.00 – Ref	<0.001
Model 5||	1.37 (1.00–1.87)	1.42 (1.10–1.83)	1.17 (0.91–1.50)	0.89 (0.71–1.12)	1.00 – Ref	0.001
Females Only (N=2,270)
Median [IQR] (watts)	50.0 [43.4–54.9]	68.9 [64.2–73.1]	84.9 [80.6–89.3]	104.1 [97.7–110.6]	144.8 [130.5–165.4]
Median [IQR] Survival, Yrs.	10.0 [5.7–17.7]	13.7 [8.2–NR]	14.7 [9.2–NR]	19.0 [11.7–NR]	16.7 [12.3–NR]	<0.001
Model 1*	2.61 (1.98–3.43)	1.60 (1.26–2.04)	1.54 (1.23–1.93)	1.06 (0.86–1.33)	1.00 – Ref	<0.001
Model 2†	1.62 (1.23–2.14)	1.33 (1.05–1.70)	1.27 (1.03–1.58)	1.00 (0.80–1.24)	1.00 – Ref	<0.001
Model 3‡	1.43 (1.05–1.93)	1.20 (0.92–1.57)	1.20 (0.95–1.51)	0.87 (0.69–1.10)	1.00 – Ref	0.003
Model 4§	1.33 (0.96–1.84)	1.15 (0.87–1.52)	1.17 (0.92–1.48)	1.17 (0.66–1.07)	1.00 – Ref	0.013
Model 5||	1.27 (0.89–1.83)	1.12 (0.83–1.52)	1.14 (0.88–1.48)	0.83 (0.65–1.07)	1.00 – Ref	0.044

Note. NR: Not reached. Ref: Reference group.

^*Model 1 is adjusted for body mass.

^†Model 2 is adjusted for model 1, age and sex (except in sex-specific strata).

^‡Model 3 is adjusted for model 2, race, leg length, smoking status, cognitive function, hypertension, diabetes, hyperlipidemia, COPD, cancer, arthritis, myocardial infarction, stroke, heart failure, kidney disease, self-rated health, hospitalization, falls, hemoglobin, albumin, C-reactive protein, glycated hemoglobin, insulin, glucose, and creatinine.

^§Model 4 is adjusted for model 3, and poor balance.

^||Model 5 is adjusted for model 4 and gait speed.

The tests for statistical interaction between muscle quality index and sex were as follows: Model 1, P<0.001; Model 2, P=0.003; Model 3, P<0.001; Model 4, P=0.002; Model 5, P=0.005.