Table 5.

Model-based standardized Z and T scores and centiles for skeletal muscle mass by sex and age group.

	Female								Male
	Mean ± SD	5th	15th	20th	50th	75th	85th	95th	Mean ± SD	5th	15th	20th	50th	75th	85th	95th
Total	6.9 ± 1	5.66	6	6.11	6.69	7.4	7.97	8.8	8.74 ± 1.33	6.8	7.4	7.6	8.61	9.58	10.06	11.09
Z score		−1.24	−0.9	−0.79	−0.21	0.5	1.07	1.9		−1.46	−1.01	−0.86	−0.1	0.63	0.99	1.77
T score		38	41	42	48	55	61	69		35	40	41	49	56	60	68
Middle age	6.86 ± 1	5.65	5.97	6.07	6.66	7.33	7.85	8.73	9.04 ± 1.29	7.26	7.77	7.92	8.89	9.81	10.31	11.39
Z score		−1.21	−0.89	−0.79	−0.2	0.47	0.99	1.87		−1.38	−0.99	−0.87	−0.12	0.59	0.98	1.81
T score		38	41	42	48	55	60	69		36	40	41	49	56	60	68
Elderly	6.93 ± 1	5.66	6.01	6.15	6.71	7.45	8.05	8.84	8.55 ± 1.32	6.64	7.21	7.42	8.41	9.43	9.91	10.92
Z score		−1.27	−0.92	−0.78	−0.22	0.52	1.12	1.91		−1.45	−1.02	−0.86	−0.11	0.67	1.03	1.8
T score		37	41	42	48	55	61	69		35	40	41	49	57	60	68
40–44 yr	7 ± 1.18	5.63	5.97	6.09	6.74	7.44	7.92	9	9.25 ± 1.29	7.36	7.98	8.19	9.17	10.05	10.56	11.47
Z score		−1.17	−0.88	−0.77	−0.22	0.37	0.78	1.7		−1.47	−0.99	−0.82	−0.06	0.62	1.01	1.72
T score		38	41	42	48	54	58	67		35	40	42	49	56	60	67
45–49 yr	6.95 ± 1.05	5.62	5.96	6.08	6.71	7.37	7.81	8.77	9.17 ± 1.23	7.38	7.93	8.12	9.05	9.94	10.47	11.5
Z score		−1.26	−0.94	−0.82	−0.23	0.39	0.81	1.73		−1.45	−1.01	−0.85	−0.1	0.62	1.06	1.89
T score		37	41	42	48	54	58	67		35	40	41	49	56	61	69
50–54 yr	6.79 ± 0.92	5.61	5.94	6.06	6.67	7.31	7.73	8.62	9.16 ± 1.39	7.34	7.85	8.03	8.93	9.81	10.37	11.47
Z score		−1.29	−0.92	−0.79	−0.12	0.57	1.03	2		−1.31	−0.94	−0.81	−0.17	0.47	0.87	1.66
T score		37	41	42	49	56	60	70		37	41	42	48	55	59	67
55–59 yr	6.76 ± 0.9	5.6	5.94	6.06	6.67	7.3	7.71	8.57	9.05 ± 1.2	7.21	7.73	7.91	8.81	9.68	10.23	11.3
Z score		−1.3	−0.92	−0.78	−0.1	0.6	1.06	2.02		−1.52	−1.09	−0.94	−0.2	0.53	0.98	1.87
T score		37	41	42	49	56	61	70		35	39	41	48	55	60	69
60–64 yr	6.87 ± 1	5.59	5.95	6.07	6.7	7.34	7.76	8.62	8.77 ± 1.29	7	7.56	7.75	8.69	9.56	10.09	11.08
Z score		−1.28	−0.93	−0.8	−0.17	0.47	0.89	1.76		−1.37	−0.94	−0.79	−0.06	0.62	1.03	1.8
T score		37	41	42	48	55	59	68		36	41	42	49	56	60	68
65–69 yr	6.91 ± 1.02	5.6	5.96	6.09	6.74	7.4	7.83	8.7	8.68 ± 1.25	6.74	7.36	7.58	8.56	9.45	9.96	10.89
Z score		−1.28	−0.93	−0.8	−0.17	0.48	0.89	1.75		−1.55	−1.05	−0.88	−0.09	0.62	1.03	1.76
T score		37	41	42	48	55	59	68		35	40	41	49	56	60	68
70–74 yr	6.93 ± 0.98	5.61	5.98	6.12	6.78	7.46	7.89	8.77	8.5 ± 1.33	6.54	7.19	7.41	8.44	9.36	9.88	10.82
Z score		−1.35	−0.97	−0.83	−0.15	0.54	0.98	1.87		−1.48	−0.99	−0.82	−0.05	0.64	1.04	1.75
T score		37	40	42	48	55	60	69		35	40	42	50	56	60	67
75–79 yr	6.94 ± 1.02	5.62	6	6.14	6.82	7.5	7.93	8.8	8.46 ± 1.37	6.43	7.07	7.29	8.32	9.27	9.83	10.85
Z score		−1.3	−0.92	−0.78	−0.12	0.55	0.98	1.83		−1.48	−1.01	−0.86	−0.1	0.59	1	1.74
T score		37	41	42	49	56	60	68		35	40	41	49	56	60	67
≥ 80 yr	6.97 ± 0.92	5.63	6.02	6.16	6.85	7.52	7.95	8.79	8.41 ± 1.38	6.36	6.97	7.18	8.2	9.17	9.76	10.88
Z score		−1.46	−1.04	−0.88	−0.14	0.6	1.06	1.98		−1.48	−1.04	−0.89	−0.15	0.55	0.98	1.79
T score		35	40	41	49	56	61	70		35	40	41	48	56	60	68

Values are presented as model-based mean ± standard deviation (SD) and percentile cutoffs (5th, 15th, 20th, 50th, 75th, 85th, and 95th) for skeletal muscle mass. Skeletal muscle mass is expressed as skeletal muscle mass index (kg/m²). Percentiles and standardized scores were derived from sex- and age-specific GAMLSS models; Z scores were calculated as Z = (X − μ)/σ and converted to T scores using T = 50 + 10 × Z. Data are stratified by sex and age group.

SD, standard deviation.