Examining the Association Between Serum Leptin and Sarcopenic Obesity

Figures & data

Table 1 Characteristics of the Study Population

Characteristic	Normal Population (N=2928)	Sarcopenia (N=178)	Obesity (N=882)	Sarcopenic Obesity (N=75)	P
Socio-demographic variables
Age (years±SD)*	72.01 (8.15)	71.85 (8.05)	69.3 (6.68)	69.47 (7.51)	<0.001
Male sex (%)^†	1423 (48.6)	70 (39.3)	534 (60.5)	41 (54.7)	<0.001
Race-ethnicity (%)^†					<0.001
Non-Hispanic White	1832 (62.6)	100 (56.2)	466 (52.8)	37 (49.3)
Smoker (%) 1 ever smoke >20 cigars in life	516 (17.6)	37 (20.8)	131 (14.9)	10 (13.3)	0.104
BMI (kg/m^2±SD)*	25.02 (3.07)	25.18 (2.67)	33.92 (3.83)	34.51 (4.71)	<0.001
Waist circumference (cm±SD)*	93.08 (10.02)	94.53 (8.94)	111.36 (9.48)	113.66 (10.62)	<0.001
Thigh skinfold (mm±SD)*	246.69 (1307.95)	547.94 (2082.28)	1475.25 (2630.89)	1310.61 (2667.74)	<0.001
Skeletal muscle index (%±SD)*	48.07 (7.17)	19.83 (2.99)	38.55 (5.56)	14.21 (2.6)	<0.001
Gait speed (m/s±SD)*	0.72 (0.21)	0.69 (0.23)	0.68 (0.2)	0.64 (0.23)	<0.001
Laboratory variables*
Leptin (mg/dL±SD)	10.03 (8)	8.12 (6.56)	23.09 (14.72)	27.08 (18.04)	<0.001
CRP (mg/dL ±SD)	0.53 (0.99)	0.58 (1.02)	0.65 (0.89)	0.67 (1.1)	0.009
Fasting Glucose (mg/dL±SD)	107.72 (42.81)	106.79 (44.26)	118.96 (49.33)	119.92 (50.09)	<0.001
Insulin (uU/mL±SD)	59,597.74 (222,362.02)	71,144.12 (242,354.44)	63,105.75 (228,496.1)	77,304.91 (253,227.57)	0.909
Total protein (g/dL±SD)	7.3 (0.48)	7.3 (0.52)	7.35 (0.47)	7.33 (0.56)	0.061
LDL cholesterol (mg/dL±SD)	139.92 (38.75)	137.99 (38.67)	146.3 (40.61)	140.7 (45.88)	0.042
Comorbidities^†
Asthma (%)	175 (6)	7 (3.9)	68 (7.7)	8 (10.7)	<0.001
Arthritis (%)	1212 (41.4)	75 (42.1)	468 (53.1)	38 (50.7)	<0.001
DM (%)	368 (12.6)	26 (14.6)	187 (21.2)	12 (16)	<0.001

Notes: *Continuous variables are presented as mean (standard deviation). ^†Categorical variables are presented as number (percentage).

Abbreviations: SD, standard deviation; BMI, body mass index; CRP, C-reactive protein; DM, diabetes mellitus; LDL, low-density lipoprotein.

Table 2 Regression Coefficients for Serum Leptin Levels and Components of Sarcopenic Obesity

	Model 1		Model 2		Model 3		Model 4
	β (95% CI)	P	β (95% CI)	P	β (95% CI)	P	β (95% CI)	P
BMI	1.35 (1.23,1.46)	<0.001	1.25 (1.15,1.35)	<0.001	1.01 (0.79,1.23)	<0.001	1.02 (0.79,1.24)	<0.001
Skeletal muscle index	−0.67 (−0.74,-0.6)	<0.001	−0.52 (−0.59,-0.45)	<0.001	−0.1 (−0.17,-0.02)	0.009	−0.1 (−0.17,-0.02)	0.009
Gaitspeed	−8.94 (−12.71,-5.18)	<0.001	−7.19 (−10.68,-3.69)	<0.001	−0.05 (−2.76,2.65)	0.966	−0.23 (−2.95,2.48)	0.866

Notes: Adjusted covariates: Model 1= unadjusted, Model 2= age, gender, race/ethnicity, Model 3= Model 2+ BMI, serum C-reactive protein, fasting glucose, waist circumference, thigh skinfold, serum insulin, total protein and low-density lipoprotein cholesterol, Model 4= Model 3+ (smoking, arthritis, asthma and diabetes mellitus).

Abbreviation: BMI, body mass index.

Table 3 Regression Coefficients for Serum Leptin Levels and 4 Groups

	Model 1		Model 2		Model 3		Model 4
	β (95% CI)	P	β (95% CI)	P	β (95% CI)	P	β (95% CI)	P
Normal	Reference(-,-)		Reference(-,-)		Reference(-,-)		Reference(-,-)
Sarcopenia	−0.89 (−4.98,3.2)	0.669	0.07 (−3.43,3.57)	0.969	−0.32 (−3.41,2.75)	0.834	−0.3 (−3.39,2.78)	0.849
Obesity	13.78 (12.21,15.35)	<0.001	12.14 (10.77,13.51)	<0.001	2.05 (0.23,3.87)	0.027	1.99 (0.16,3.83)	0.032
Sarcopenic obesity	19.22 (13.72,24.72)	<0.001	17.12 (12.41,21.83)	<0.001	6.97 (2.61,11.33)	0.002	6.95 (2.59,11.32)	0.002

Notes: Adjusted covariates: Model 1= unadjusted, Model 2= age, gender, race/ethnicity, Model 3= Model 2+ BMI, serum C-reactive protein and fasting glucose, waist circumference, thigh skinfold, serum insulin, total protein and low-density lipoprotein cholesterol, Model 4= Model 3+ (smoking, arthritis, asthma and diabetes mellitus).