Table 6.

Muscle thickness and echogenicity across age categories in adults stratified for sex and BMI

	Abdomen
Women					Men
Quartile	Age	MT (mm)	EG (%)	MT/SAT	Age	MT (mm)	EG (%)	MT/SAT
Normal weight					Normal weight
I	18–25 years	16.09 ± 2.30 (n = 100)	53.48 ± 9.53 (n = 100)	1.75 ± 1.08 (n = 100)	18–23 years	17.30 ± 2.96 (n = 176)	53.86 ± 12.26 (n = 176)	2.77 ± 1.53 (n = 176)
II	26–38 years	14.83 ± 2.91 (n = 91)	58.64 ± 8.57 (n = 91)	1.17 ± 0.69 (n = 91)	24–31 years	18.43 ± 3.30 (n = 169)	56.24 ± 10.73 (n = 169)	2.01 ± 0.98 (n = 169)
III	39–49 years	12.80 ± 2.64 (n = 60)	66.61 ± 8.53 (n = 60)	0.86 ± 0.68 (n = 60)	32–45 years	16.84 ± 2.11 (n = 108)	59.08 ± 10.84 (n = 108)	1.76 ± 0.84 (n = 108)
IV	50–89 years	11.31 ± 2.82 (n = 49)	76.10 ± 8.95 (n = 49)	0.61 ± 0.40 (n = 49)	46–84 years	16.32 ± 3.45 (n = 148)	62.48 ± 11.80 (n = 148)	1.39 ± 1.04 (n = 148)
	p	< 0.001	< 0.001	< 0.001	p	< 0.001	< 0.001	< 0.001
Overweight					Overweight
I	18–25 years	15.85 ± 3.22 (n = 18)	59.96 ± 9.75 (n = 18)	0.48 ± 0.15 (n = 18)	18–23 years	18.18 ± 2.94 (n = 88)	55.96 ± 10.53 (n = 88)	1.35 ± 0.86 (n = 88)
II	26–38 years	15.58 ± 2.66 (n = 22)	57.12 ± 10.33 (n = 22)	0.63 ± 0.31 (n = 22)	24–31 years	18.42 ± 3.70 (n = 72)	54.79 ± 10.80 (n = 72)	1.29 ± 0.82 (n = 72)
III	39–49 years	13.51 ± 2.66 (n = 40)	69.04 ± 11.06 (n = 40)	0.52 ± 0.28 (n = 40)	32–45 years	17.09 ± 3.00 (n = 120)	59.68 ± 12.91 (n = 120)	0.92 ± 0.47 (n = 120)
IV	50–89 years	11.65 ± 3.16 (n = 52)	73.64 ± 11.79 (n = 52)	0.45 ± 0.12 (n = 52)	46–84 years	14.89 ± 3.41 (n = 96)	66.10 ± 14.81 (n = 96)	0.75 ± 0.62 (n = 96)
	p	< 0.001	< 0.001	0.019	p	< 0.001	< 0.001	< 0.001
Obesity					Obesity
I	18–25 years	16.18 ± 2.90 (n = 8)	65.28 ± 14.30 (n = 8)	0.30 ± 0.06 (n = 8)	18–23 years	17.83 ± 3.47 (n = 9)	52.51 ± 17.18 (n = 9)	0.47 ± 0.27 (n = 9)
II	26–38 years	12.39 ± 1.93 (n = 12)	48.85 ± 8.18 (n = 12)	0.27 ± 0.10 (n = 12)	24–31 years	19.78 ± 3.68 (n = 43)	50.54 ± 11.50 (n = 43)	0.69 ± 0.24 (n = 43)
III	39–49 years	14.36 ± 2.83 (n = 24)	64.08 ± 9.85 (n = 24)	0.36 ± 0.10 (n = 24)	32–45 years	15.97 ± 3.04 (n = 38)	57.36 ± 12.62 (n = 38)	0.45 ± 0.13 (n = 38)
IV	50–89 years	12.35 ± 2.73 (n = 37)	61.90 ± 14.00 (n = 37)	0.32 ± 0.11 (n = 37)	46–84 years	14.04 ± 2.87 (n = 50)	62.07 ± 8.26 (n = 50)	0.33 ± 0.08 (n = 50)
	p	0.001	0.004	0.137	p	< 0.001	< 0.001	< 0.001
	Thigh
Women					Men
Normal weight					Normal weight
I	18–27 years	38.64 ± 7.48 (n = 103)	38.00 ± 14.14 (n = 103)	3.36 ± 1.57 (n = 215)	18–22 years	41.14 ± 7.63 (n = 166)	35.97 ± 13.63 (n = 166)	7.78 ± 3.34 (n = 166)
II	28–40 years	32.81 ± 8.06 (n = 180)	47.90 ± 15.88 (n = 180)	2.51 ± 0.85 (n = 180)	23–30 years	40.61 ± 8.73 (n = 192)	44.63 ± 11.74 (n = 192)	7.50 ± 3.26 (n = 192)
III	41–50 years	29.93 ± 6.91 (n = 127)	54.62 ± 14.90 (n = 127)	2.20 ± 0.88 (n = 127)	31–45 years	40.25 ± 7.66 (n = 117)	41.86 ± 13.01 (n = 117)	8.47 ± 3.66 (n = 117)
IV	51–89 years	28.42 ± 7.26 (n = 103)	56.60 ± 16.65 (n = 103)	2.12 ± 1.02 (n = 103)	46–84 years	32.25 ± 6.30 (n = 142)	48.65 ± 14.02 (n = 142)	6.28 ± 1.99 (n = 142)
	p	< 0.001	< 0.001	< 0.001	p	< 0.001	< 0.001	< 0.001
Overweight					Overweight
I	18–27 years	36.93 ± 7.58 (n = 41)	41.55 ± 14.64 (n = 41)	1.93 ± 0.68 (n = 41)	18–22 years	39.73 ± 9.00 (n = 64)	44.11 ± 15.48 (n = 64)	4.70 ± 1.85 (n = 64)
II	28–40 years	33.09 ± 6.80 (n = 52)	46.81 ± 15.71 (n = 52)	1.74 ± 0.59 (n = 52)	23–30 years	41.50 ± 8.77 (n = 75)	44.15 ± 15.79 (n = 75)	5.47 ± 2.18 (n = 75)
III	41–50 years	32.16 ± 7.05 (n = 107)	50.67 ± 14.23 (n = 107)	1.84 ± 0.65 (n = 107)	31–45 years	40.48 ± 7.42 (n = 130)	46.48 ± 13.74 (n = 130)	5.67 ± 3.04 (n = 130)
IV	51–89 years	27.07 ± 6.71 (n = 106)	56.41 ± 16.83 (n = 106)	1.55 ± 0.47 (n = 106)	46–84 years	32.23 ± 8.28 (n = 91)	56.41 ± 15.83 (n = 91)	4.54 ± 1.68 (n = 91)
	p	< 0.001	< 0.001	< 0.001	p	< 0.001	< 0.001	0.001
Obesity					Obesity
I	18–27 years	37.27 ± 5.12 (n = 14)	49.54 ± 12.96 (n = 14)	1.78 ± 0.81 (n = 14)	18–22 years	46.01 ± 10.65 (n = 9)	30.39 ± 12.66 (n = 9)	2.60 ± 0.93 (n = 9)
II	28–40 years	34.71 ± 12.62 (n = 25)	38.28 ± 12.83 (n = 25)	1.53 ± 0.64 (n = 25)	23–30 years	51.30 ± 10.11 (n = 33)	31.65 ± 13.86 (n = 33)	4.66 ± 2.03 (n = 33)
III	41–50 years	31.19 ± 7.16 (n = 48)	59.22 ± 16.87 (n = 48)	1.40 ± 0.42 (n = 48)	31–45 years	39.73 ± 8.61 (n = 46)	41.00 ± 16.38 (n = 46)	2.93 ± 1.02 (n = 46)
IV	51–89 years	28.40 ± 8.32 (n = 67)	53.14 ± 21.29 (n = 67)	1.38 ± 0.57 (n = 67)	46–84 years	32.68 ± 6.81 (n = 47)	55.68 ± 16.70 (n = 47)	3.17 ± 1.15 (n = 47)
	p	0.012	< 0.001	0.891	p	< 0.001	< 0.001	< 0.001
Hip					Chest
Normal weight					Normal weight
I	18–33 years	20.91 ± 4.85 (n = 109)	60.90 ± 10.94 (n = 109)	2.77 ± 1.41 (n = 109)	18–24 years	27.07 ± 5.98 (n = 126)	47.57 ± 10.88 (n = 126)	8.23 ± 3.53 (n = 126)
II	34–43 years	20.37 ± 4.63 (n = 118)	64.55 ± 10.67 (n = 118)	2.49 ± 1.51 (n = 118)	25–31 years	29.30 ± 7.10 (n = 136)	52.14 ± 11.49 (n = 136)	6.87 ± 3.58 (n = 136)
III	44–51 years	21.05 ± 4.21 (n = 76)	71.70 ± 11.19 (n = 76)	2.00 ± 1.06 (n = 76)	32–46 years	28.91 ± 7.23 (n = 115)	52.45 ± 11.97 (n = 115)	7.05 ± 3.79 (n = 115)
IV	52–74 years	18.60 ± 3.80 (n = 75)	75.76 ± 9.64 (n = 75)	2.10 ± 1.08 (n = 75)	47–74 years	24.96 ± 7.50 (n = 134)	64.22 ± 12.02 (n = 134)	6.07 ± 2.93 (n = 134)
	p	0.002	< 0.001	< 0.001	p	< 0.001	< 0.001	< 0.001
Overweight					Overweight
I	18–33 years	23.51 ± 4.03 (n = 50)	63.31 ± 13.63 (n = 50)	1.29 ± 0.40 (n = 50)	18–24 years	28.13 ± 6.39 (n = 73)	56.60 ± 10.74 (n = 73)	5.34 ± 3.51 (n = 73)
II	34–43 years	22.61 ± 3.69 (n = 21)	64.33 ± 12.82 (n = 21)	1.39 ± 0.74 (n = 21)	25–31 years	28.49 ± 7.38 (n = 51)	56.58 ± 13.67 (n = 51)	4.91 ± 2.52 (n = 51)
III	44–51 years	21.07 ± 0.55 (n = 71)	68.95 ± 13.91 (n = 71)	1.19 ± 0.34 (n = 71)	32–46 years	27.57 ± 7.30 (n = 104)	62.31 ± 13.95 (n = 104)	3.73 ± 2.54 (n = 104)
IV	52–74 years	20.32 ± 3.95 (n = 84)	72.15 ± 12.98 (n = 84)	1.10 ± 0.29 (n = 84)	47–74 years	24.36 ± 8.71 (n = 75)	68.21 ± 14.01 (n = 75)	2.37 ± 1.91 (n = 75)
	p	< 0.001	0.002	0.005	p	0.004	< 0.001	< 0.001
Obesity					Obesity
I	18–33 years	25.84 ± 2.77 (n = 18)	63.56 ± 11.84 (n = 18)	1.07 ± 0.20 (n = 18)	18–24 years	36.55 ± 3.19 (n = 3)	73.38 ± 2.46 (n = 3)	1.71 ± 0.30 (n = 3)
II	34–43 years	20.85 ± 3.07 (n = 16)	68.35 ± 10.02 (n = 16)	1.04 ± 0.33 (n = 16)	25–31 years	33.27 ± 6.18 (n = 15)	55.91 ± 9.29 (n = 15)	2.27 ± 0.77 (n = 15)
III	44–51 years	22.06 ± 3.80 (n = 42)	69.64 ± 11.70 (n = 42)	0.98 ± 0.27 (n = 42)	32–46 years	30.67 ± 5.54 (n = 31)	55.03 ± 11.12 (n = 31)	2.14 ± 0.58 (n = 31)
IV	52–74 years	22.36 ± 4.97 (n = 41)	69.46 ± 11.11 (n = 41)	1.03 ± 0.30 (n = 41)	47–74 years	24.72 ± 6.92 (n = 27)	69.23 ± 13.68 (n = 27)	1.53 ± 0.73 (n = 27)
	p	0.002	0.241	0.657	p	< 0.001	< 0.001	0.002
Triceps
Normal weight
I	18–33 years	31.59 ± 7.26 (n = 125)	41.15 ± 14.72 (n = 125)	2.79 ± 1.07 (n = 125)
II	34–44 years	31.57 ± 7.35 (n = 130)	43.50 ± 14.99 (n = 130)	2.31 ± 0.79 (n = 130)
III	45–53 years	32.80 ± 6.77 (n = 79)	48.60 ± 12.81 (n = 79)	2.29 ± 0.59 (n = 79)
IV	54–89 years	31.33 ± 6.43 (n = 80)	50.37 ± 15.49 (n = 80)	2.28 ± 0.67 (n = 80)
	p	0.536	< 0.001	< 0.001
Overweight
I	18–33 years	32.67 ± 7.12 (n = 51)	46.45 ± 15.14 (n = 51)	1.85 ± 0.46 (n = 51)
II	34–44 years	35.61 ± 5.56 (n = 50)	41.59 ± 14.13 (n = 50)	1.86 ± 0.54 (n = 50)
III	45–53 years	33.30 ± 4.78 (n = 86)	42.87 ± 14.41 (n = 86)	1.71 ± 0.35 (n = 86)
IV	54–89 years	31.03 ± 6.23 (n = 78)	49.18 ± 13.88 (n = 78)	1.75 ± 0.43 (n = 78)
	p	< 0.001	0.009	0.006
Obesity
I	18–33 years	33.81 ± 5.37 (n = 28)	41.69 ± 14.18 (n = 28)	1.65 ± 0.46 (n = 28)
II	34–44 years	31.93 ± 5.63 (n = 28)	43.43 ± 15.94 (n = 28)	1.59 ± 0.23 (n = 28)
III	45–53 years	31.12 ± 5.75 (n = 45)	50.09 ± 14.36 (n = 45)	1.49 ± 0.32 (n = 45)
IV	54–89 years	31.10 ± 5.11 (n = 52)	50.02 ± 18.54 (n = 52)	1.52 ± 0.27 (n = 52)
	p	0.150	0.055	0.165

Data are expressed as mean ± SD. Difference between groups were compared by one-way ANOVA, followed by Bonferroni test as post-hoc test. A p value in bold type denotes a significant difference (p < 0.05)

Abbreviations: subcutaneous adipose tissue, SAT; muscle thickness, MT; echogenicity, EG; standard deviation, SD