Higher Serum Leptin Levels are Associated with a Reduced Risk of Sarcopenia but a Higher Risk of Dynapenia Among Older Adults

Figures & data

Figure 1 Algorithm for sarcopenia diagnosis by 2019 Asia Working Group of Sarcopenia (AWGS).

Abbreviations: F, female; M, male.

Table 1 Characteristics of Study Participants

	Quartiles of Serum Leptin Levels (ng/mL)
	Male						Female
	Q1	Q2	Q3	Q4	Total	p- value	Q1	Q2	Q3	Q4	Total	p- value
	(<2.304)	(2.304 to<3.404)	(3.404 to<5.29)	(≥5.298)	N=204		(<4.934)	(4.934 to<8.536)	(8.536 to<14.240)	(≥14.240)	N=256
	n=51	n=51	n=51	n=51			n=64	n=64	n=64	n=64
Continuous variables^a.
Age, years	72.9(8.3)	70.2(6.9)	72.4(6.9)	73.1(7.4)	72.2(7.5)	0.195	70.4(4.9)	72.8(6.9)	71.1(5.1)	71.4(5.9)	71.4(5.8)	0.128
BMI, kg/m^2	22.2(2.3)	23.9(2.1)	26.2(2.5)	27.4(3.5)	24.9(3.3)	<0.001	21.1(2.4)	22.6(2.4)	25.4(4.2)	26.8(3.2)	23.9(3.8)	<0.001
WC, cm	77.2(5.1)	82.4(5.6)	87.7(6.5)	91.1(8.1)	84.6(8.3)	<0.001	70.5(6.1)	75.0(8.1)	77.2(10.0)	84.1(9.1)	76.7(9.7)	<0.001
SMI, kg/m^2	7.2(0.7)	7.5(0.8)	7.7(0.9)	7.7(0.8)	7.5(0.8)	0.014	5.7(0.5)	5.6(0.6)	6.1(0.8)	6.2(0.6)	5.9(0.7)	<0.001
HGS, kg	33.3(8.1)	34.8(7.6)	33.9(6.9)	31.8(8.4)	33.4(7.8)	0.254	19.7(5.8)	20.5(5.2)	20.5(4.6)	20.0(4.8)	20.2(5.1)	0.767
Gait speed, m/s	1.21(0.35)	1.24(0.31)	1.09(0.32)	1.07(0.31)	1.15(0.34)	0.028	1.17(0.32)	1.08(0.34)	1.14(0.24)	1.02(0.29)	1.11(0.31)	0.025
PA, kcal/week	11,101.8 (5511.7)	10,374.3 (3045.9)	9336.2 (2785.4)	10,034.1 (3200.3)	10,211.6 (3822.1)	0.130	10,160.7 (2847.4)	10,353.7 (3213.8)	10,141.2 (3376.9)	10,422.1 (3017.6)	10,269.1 (3103.8)	0.186
Fat mass, kg	12.2(3.2)	16.4(3.5)	20.1(4.3)	24.1(6.6)	18.2(6.3)	<0.001	13.7(3.6)	17.8(3.8)	21.9(4.2)	25.2(5.8)	19.6(6.2)	<0.001
Body fat, %	20.7(4.6)	24.9(4.1)	28.1(4.5)	32.1(5.5)	26.4(6.3)	<0.001	27.7(5.4)	33.5(4.1)	36.9(4.2)	40.1(5.3)	34.5(6.6)	<0.001
FMR	0.49(0.15)	0.61(0.14)	0.72(0.17)	0.89(0.22)	0.67(0.22)	<0.001	0.74(0.21)	0.96(0.18)	1.11(0.19)	1.28(0.31)	1.02(0.30)	<0.001
Leptin,	1.92(0.28)	2.87(0.31)	4.15(0.55)	9.44(5.64)	4.59(4.05)	<0.001	3.47(0.92)	6.62(0.93)	11.03(1.67)	25.21(18.43)	11.58(12.42)	<0.001
Categorical variables^b
Smoke	21(41.1)	24(47.1)	22(43.1)	31(60.8)	98(48.1)	0.188	5(7.8)	1(1.5)	0 (0)	1(1.5)	7(2.7)	0.035
AC	2(3.9)	6(11.7)	7 (13.7)	5(9.8)	20(9.8)	0.376	2(3.1)	1(1.5)	0 (0)	1(1.5)	4(1.5)	0.567
≥ 1 time/week
HTN	14(27.4)	21(41.1)	25(49.0)	25(49.0)	85(41.6)	0.108	18(28.1)	22(34.3)	21(32.8)	26(40.6)	87(33.9)	0.546
DM	5 (9.8)	7(13.7)	11(21.5)	10(19.6)	33(16.2)	0.378	5 (7.8)	7(10.9)	8(12.5)	12(18.7)	32(12.5)	0.317
Stroke	1 (1.9)	0 (0)	5 (9.8)	0 (0)	6 (2.9)	0.009	2 (3.1)	1 (1.5)	1 (1.5)	2 (3.1)	6 (2.3)	0.881
CAD	2 (3.9)	2 (3.9)	3 (5.8)	5 (9.8)	12(5.8)	0.574	5 (7.8)	2 (3.1)	1 (1.5)	5 (7.8)	13 (5.1)	0.228
MetS	4 (7.8)	8(15.6)	19(37.2)	20(39.2)	51(25.0)	<0.001	4 (6.2)	13(20.3)	17(26.5)	31(48.4)	65(25.3)	<0.001
Dynapenia	8 (15.6)	10(19.6)	17(33.3)	16(31.3)	51(25.0)	0.105	10(15.6)	14(21.8)	16(25)	19(29.6)	59(23.0)	0.288
Sarcopenia	11(21.5)	8(15.6)	2(3.9)	7(13.7)	28(13.7)	0.073	12(18.7)	19(29.6)	8(12.5)	7(10.9)	46(17.9)	0.024

Notes: ^aValues in the continuous variables were expressed as mean (standard deviation) unless otherwise specified. The differences among leptin quartiles were examined by ANOVA test. ^bValues in the categorical variables were expressed as number (percent). Chai-square test was used to examine the differences of these variables.

Abbreviations: BMI, body mass index; WC, waist circumference; SMI, skeletal muscle mass index; HGS, handgrip strength; PA, physical activity; FMR, fat to muscle ratio; AC, alcohol consumption; HTN, hypertension; DM, diabetes mellitus; CAD, coronary artery disease; MetS, metabolic syndrome.

Table 2 Correlation Between Serum Leptin Levels and Body Composition, Muscle Function

	Male		Female
Variables	r	p-value	r	p-value
SMI (kg/m^2)	0.186	0.009	0.213	0.001
Handgrip strength (kg)	−0.170	0.015	−0.142	0.023
Gait speed (m/s)	−0.174	0.014	−0.213	0.001
BMI (kg/m^2)	0.534	<0.001	0.471	<0.001
Waist circumference (cm)	0.569	<0.001	0.427	<0.001
Fat mass (kg)	0.639	<0.001	0.579	<0.001
Body fat percentage (%)	0.564	<0.001	0.533	<0.001
Fat to muscle ratio	0.582	<0.001	0.559	<0.001

Note: Pearson’s correlation was performed to examine the relationship between serum leptin level and variables.

Abbreviations: BMI, body mass index; SMI, skeletal muscle mass index.

Table 3 Serum Leptin Level and Risk of Dynapenia and Sarcopenia

		Dynapenia			Sarcopenia
Models	Leptin Quartiles	OR (95% CI)	p-value	p for Trend	OR (95% CI)	p-value	p for Trend
Male
Model 1	Q2 vs Q1	1.41 (0.47–4.18)	0.540	0.015	1.12 (0.34–3.68)	0.851	0.039
	Q3 vs Q1	2.95 (1.09–8.02)	0.033		0.12 (0.02–0.64)	0.014
	Q4 vs Q1	2.90 (1.05–7.98)	0.039		0.41 (0.12–1.41)	0.158
Model 2	Q2 vs Q1	1.58(0.50–4.97)	0.435	0.040	0.62(0.16–2.41)	0.487	0.002
	Q3 vs Q1	2.48 (0.79–7.72)	0.117		0.02 (0.01–0.26)	0.003
	Q4 vs Q1	3.74 (0.99–14.17)	0.052		0.06 (0.01–0.48)	0.008
Female
Model 1	Q2 vs Q1	1.42 (0.56–3.58)	0.454	0.052	1.35 (0.55–3.30)	0.504	0.038
	Q3 vs Q1	1.69 (0.68–4.20)	0.252		0.49 (0.18–1.36)	0.175
	Q4 vs Q1	2.35 (0.97–5.70)	0.058		0.44 (0.15–1.28)	0.135
Model 2	Q2 vs Q1	1.68 (0.62–4.52)	0.300	0.042	1.17 (0.44–3.12)	0.749	0.023
	Q3 vs Q1	2.27 (0.78–6.57)	0.128		0.33 (0.09–1.12)	0.075
	Q4 vs Q1	3.32 (1.03–10.74)	0.045		0.26 (0.06–1.17)	0.079

Notes: Quartile-based multiple logistic regression analysis was used to examine the risk of dynapenia and sarcopenia. Adjusted covariates: Model 1= age, health behaviors (smoking, alcohol consumption). Model 2= Model 1+ hypertension, diabetes, stroke, coronary artery disease, physical activity, fat to muscle ratio.

Abbreviations: OR, odds ratio; CI, confidence interval.