Influence of Central Obesity on Associations Between Physical Activity, Sitting Time, and Metabolic Syndrome Among Middle-Aged and Older Adults in Urban China: A Cross-Sectional Study

Figures & data

Figure 1 Flow chart of study population.

Abbreviations: WC, waist circumference; MRI, magnetic resonance imaging.

Table 1 Sociodemographic Characteristics, Lifestyle and Metabolic Parameters of the Total Sample and Across MetS Status

Characteristic	All	Non-MetS	MetS	P value
	N=957	N=800	N=157
Sex: male, N (%)	386 (40.3%)	288 (36.0%)	98 (62.4%)	0.000*
Age (y)	53.1 ± 6.8	52.8 ± 6.7	54.6 ± 6.7	0.003*^a
Smoke, N (%)	295 (30.8%)	215 (26.9%)	80 (51.0%)	0.000*
Alcohol use, N (%)	411 (42.9%)	324 (40.5%)	87 (55.4%)	0.001*
Drink tea, N (%)	667 (69.7%)	541 (67.6%)	126 (80.3%)	0.002*
Sleep duration (≥8 h/day), N (%)	450 (47.0%)	364 (45.5%)	86 (54.8%)	0.033*
Marital status: married, N (%)	900 (94.0%)	753 (94.1%)	147 (93.6%)	0.811
Education, N (%)^#				0.688
Illiterate or primary	94 (9.8%)	76 (9.5%)	18 (11.5%)
Junior high school	431 (45.1%)	364 (45.5%)	67 (42.9%)
High school or higher	431 (45.1%)	360 (45.0%)	71 (45.5%)
Dietary pattern, N (%)				0.243
Meat-based diet	75 (7.8%)	58 (7.2%)	17 (10.8%)
Half meat half vegetarian	659 (68.9%)	551 (68.9%)	108 (68.8%)
Vegetarian diet	223 (23.3%)	191 (23.9%)	32 (20.4%)
Physical activity, N (%)				0.008*
Low	214 (22.4%)	167 (20.9%)	47 (29.9%)
Moderate	473 (49.4%)	394 (49.3%)	79 (50.3%)
High	270 (28.2%)	239 (29.9%)	31 (19.7%)
Sitting time (h/day)	4.0 (3.0,6.0)	4.0 (2.6,6.0)	5.0 (3.0,8.0)	0.008*^b
Sitting time, N (%)				0.029*
≤3 (h/day)	370 (38.7%)	321 (40.1%)	49 (31.2%)
3–6 (h/day)	349 (36.5%)	292 (36.5%)	57 (36.3%)
>6 (h/day)	238 (24.9%)	187 (23.4%)	51 (32.5%)
Abdominal WC, N (%)	162 (16.9%)	69 (8.6%)	93 (59.2%)	0.000*
Increased glucose concentration, N (%)	191 (20.0%)	102 (12.8%)	89 (56.7%)	0.000*
Elevated blood pressure, N (%)	514 (53.7%)	372 (46.5%)	142 (90.4%)	0.000*
Increased TG concentration, N (%)	294 (30.7%)	157 (19.6%)	137 (87.3%)	0.000*
Decreased HDL-C concentration, N (%)	88 (9.2%)	26 (3.3%)	62 (39.5%)	0.000*

Notes: Values are presented as mean ± standard deviation (SD), median (interquartile range), or percent prevalence. P values calculated by chi-square test unless otherwise indicated. Versus the group of Non-MetS, *P<0.05. ^#Education was missing for 1 participant; therefore, total add up to 956. ^aT-test P value. ^bMann–Whitney U-test P value. Variables with statistical significance are shown in boldface. Abdominal WC was defined as WC ≥ 90 cm for men and ≥85 cm for women; increased glucose concentration was defined as FPG ≥ 110 mg/dL or 2hPG ≥ 140 mg/dL and (or) those who have been diagnosed with diabetes and treated; elevated blood pressure was referred to as blood pressure ≥ 130/85 mmHg and (or) confirmed hypertension and treated; increased TG concentration was referred to as fasting TG ≥ 150 mg/dL; and decreased HDL-C concentration means fasting HDL-C < 40 mg/dL.²⁶

Abbreviations: MetS, metabolic syndrome; WC, waist circumference; TG, triglyceride; HDL-C, high-density lipoprotein cholesterol.

Table 2 Prevalence of Metabolic Parameters and MetS According to Physical Activity Levels

Parameter	Low	Moderate	High	P value
	N=214	N=473	N=270
BMI (kg/m^2)	23.7 ± 3.1	23.5 ± 2.8	23.3 ± 3.0	0.355^a
WC (cm)	79.9 ± 9.4	78.5 ± 8.8	77.8 ± 9.3*	0.037^a
VFA (cm^2)	76.7 (51.5, 115.5)	70.1 (46.5, 109.7)	67.5 (43.8, 107.5)	0.059
SFA (cm^2)	152.7(118.2, 206.4)	154.6(118.4, 198.3)	148.7(115.3, 203.9)	0.689
TG (mg/dL)	125.0 (87.5, 176.5)	115.0 (84.0, 166.0)	112.0(80.8, 152.5)*	0.015
HDL-C (mg/dL)	53.0 (45.0, 62.5)	55.0 (47.0, 64.0)	56.0 (48.0, 66.0)*	0.021
FPG (mg/dL)	88.0 (81.0, 96.0)	88.0 (81.0, 97.0)	87.0 (80.0, 95.0)	0.393
2hPG (mg/dL)	99.0 (82.0, 130.0)	98.0 (82.0, 124.0)	97.5 (81.0, 116.0)	0.327
Fasting insulin (mmol/L)	18.5 (14.7, 23.6)	17.8 (13.6, 23.3)	17.4 (13.3, 22.5)	0.099
HOMA-IR	4.0 (3.1, 5.5)	3.8 (2.9, 5.5)	3.7 (2.7, 5.2)	0.125
SBP (mmHg)	124.4 ± 17.1	124.6 ± 17.0	123.6 ± 15.8	0.796^a
DBP (mmHg)	81.3 ± 10.3	81.1 ± 9.9	80.6 ± 9.9	0.620^a
MetS, N (%)	47 (22.0%)	79 (16.7%)*	31 (11.5%)*^#	0.008^b

Notes: Values are presented as mean ± SD, median (interquartile range), or percent prevalence. P values calculated by non-parametric Kruskal–Wallis test unless otherwise indicated. Versus the group of Low PA, *P<0.05. Versus the group of Moderate PA, ^#P<0.05. ^aANOVA P value. ^bChi-square P value. Variables with statistical significance are shown in boldface.

Abbreviations: SFA, subcutaneous fat area; VFA, visceral fat area; FPG, fasting plasma glucose; 2hPG, 2-hour post-load plasma glucose; HOMA-IR, homeostatic model assessment of insulin resistance; SBP, systolic blood pressure; DBP, diastolic blood pressure.

Table 3 Prevalence of Metabolic Parameters and MetS According to Sitting Time

Parameter	≤3h	3–6h	>6h	P value
	N=370	N=349	N=238
BMI (kg/m^2)	23.6 ± 3.2	23.4 ± 2.9	23.4 ± 2.6	0.610^a
WC (cm)	78.4 ± 9.4	78.3 ± 9.1	79.4 ± 8.6	0.305^a
VFA (cm^2)	71.0 (44.8, 114.2)	67.7 (45.3, 106.9)	74.0 (48.2, 113.5)	0.307
SFA (cm^2)	153.2(116.6, 206.1)	152.8(117.4, 199.2)	154.4(117.5, 198.7)	0.918
TG (mg/dL)	113.0 (83.3, 151.8)	119.0 (85.3, 164.5)	118.0 (85.0, 177.5)	0.133
HDL-C (mg/dL)	56.0 (48.0, 65.0)	54.0 (45.0, 63.0)	54.0 (46.0, 63.0)*	0.029
FPG (mg/dL)	88.0 (81.0, 97.0)	87.5 (80.0, 95.0)	87.0 (81.5, 94.5)	0.202
2hPG (mg/dL)	100.0 (83.0, 129.0)	97.0 (80.0, 118.0)	97.0 (81.0, 123.0)	0.121
Fasting insulin (mmol/L)	17.5 (13.3, 22.8)	17.6 (13.7, 22.9)	18.5 (14.4, 23.7)	0.234
HOMA-IR	3.8 (2.9, 5.5)	3.7 (2.9, 5.2)	4.1 (3.1, 5.5)	0.255
SBP (mmHg)	125.6 ± 16.9	123.3 ± 16.3	123.4 ± 16.8	0.115^a
DBP (mmHg)	80.6 ± 10.2	80.5 ± 9.4	82.2 ± 10.2	0.086^a
MetS, N (%)	49 (13.2%)	57 (16.3%)*	51 (21.4%)*^#	0.029^b

Notes: Values are presented as mean ± SD, median (interquartile range), or percent prevalence. P values calculated by non-parametric Kruskal–Wallis test unless otherwise indicated. Versus the group with ST of ≤3h, *P<0.05. Versus the group with ST for 3–6h, ^#P<0.05. ^aANOVA P value. ^bChi-square P value. Variables with statistical significance are shown in boldface.

Table 4 Odds Ratio for the MetS and Its Components Depending on Physical Activity (or, 95% CI)

PA		Total				Non-central obesity			Central obesity
		OR (95% CI)		P		OR (95% CI)	P		OR (95% CI)		P
Model1 unadjusted
Metabolic syndrome
Low		1.00				1.00			1.00
Moderate		0.71 (0.48, 1.07)		0.100		1.97 (0.56, 6.99)	0.294		0.63 (0.38, 1.04)		0.071
High		0.46(0.28, 0.76)		0.002		1.63 (0.41, 6.45)	0.485		0.38 (0.21, 0.70)		0.002
P for trend				0.009*			0.570				0.008*
Abdominal WC
Low		1.00				1.00			1.00
Moderate		0.74 (0.49, 1.12)		0.152		1.68 (0.46, 6.05)	0.430		0.70 (0.43, 1.16)		0.167
High		0.63 (0.40, 1.12)		0.059		0.68 (0.14, 3.44)	0.644		0.74 (0.42, 1.31)		0.296
P for trend				0.151			0.339				0.365
Increased glucose concentration
Low		1.00				1.00			1.00
Moderate		0.95 (0.65, 1.40)		0.799		1.69 (0.86, 3.32)	0.127		0.71 (0.43, 1.20)		0.200
High		0.62 (0.39, 0.98)		0.042		1.37 (0.65, 2.87)	0.406		0.37 (0.19, 0.72)		0.003
P for trend				0.068			0.293				0.012*
Elevated blood pressure
Low		1.00				1.00			1.00
Moderate		1.12 (0.81, 1.55)		0.482		1.36 (0.87, 2.13)	0.171		1.04 (0.61, 1.79)		0.884
High		1.06 (0.74, 1.52)		0.749		1.34 (0.83, 2.18)	0.232		0.99 (0.54, 1.84)		0.983
P for trend				0.773			0.364				0.981
Increased TG concentration
Low		1.00				1.00			1.00
Moderate		0.84 (0.60, 1.12)		0.330		1.03 (0.59, 1.79)	0.932		0.82 (0.50, 1.34)		0.435
High		0.66 (0.45, 0.98)		0.038		1.02 (0.55, 1.88)	0.951		0.53 (0.30, 0.94)		0.028
P for trend				0.110			0.996				0.076
Decreased HDL-C concentration
Low		1.00				1.00			1.00
Moderate		0.58 (0.35, 0.94)		0.029		1.03 (0.39, 2.73)	0.950		0.48 (0.26, 0.88)		0.019
High		0.35 (0.18, 0.66)		0.001		0.45 (0.12, 1.62)	0.219		0.36 (0.16, 0.77)		0.009
P for trend				0.004*			0.324				0.013*
Model2 adjusted
Metabolic syndrome
Low	1.00				1.00					1.00
Moderate	0.73 (0.44, 1.21)		0.221		2.73 (0.68, 11.01)			0.157		0.54 (0.29, 0.99)	0.046
High	0.46 (0.25, 0.86)		0.014		2.31 (0.50, 10.68)			0.285		0.33 (0.16, 0.70)	0.003
P for trend			0.049*					0.368			0.012*
Abdominal WC
Low	1.00				1.00					1.00
Moderate	0.85 (0.48, 1.54)		0.599		2.24 (0.48, 10.51)			0.308		0.67 (0.34, 1.32)	0.247
High	0.66 (0.33, 1.33)		0.244		0.94 (0.12, 7.42)			0.950		0.68 (0.30, 1.54)	0.359
P for trend			0.500					0.430			0.488
Increased glucose concentration
Low	1.00				1.00					1.00
Moderate	0.93 (0.61, 1.41)		0.731		1.79 (0.87, 3.67)			0.112		0.64 (0.37, 1.12)	0.120
High	0.60 (0.36, 0.98)		0.042		1.39 (0.63, 3.06)			0.413		0.31 (0.15, 0.64)	0.002
P for trend			0.074					0.259			0.007*
Elevated blood pressure
Low	1.00				1.00					1.00
Moderate	1.10 (0.77, 1.57)		0.619		1.25 (0.78, 2.02)			0.361		0.98 (0.55, 1.77)	0.950
High	1.16 (0.77, 1.74)		0.477		1.25 (0.74, 2.11)			0.405		1.01 (0.51, 2.00)	0.976
P for trend			0.774					0.628			0.995
Increased TG concentration
Low	1.00				1.00					1.00
Moderate	0.81 (0.54, 1.22)		0.314		0.90 (0.47, 1.71)			0.740		0.73 (0.41, 1.29)	0.277
High	0.75 (0.47, 1.19)		0.214		0.98 (0.48, 1.99)			0.949		0.56 (0.29, 1.09)	0.089
P for trend			0.439					0.927			0.234
Decreased HDL-C concentration
Low	1.00				1.00					1.00
Moderate	0.55 (0.31, 0.97)		0.038		0.87 (0.29, 2.67)			0.812		0.42 (0.21, 0.85)	0.015
High	0.38 (0.18, 0.78)		0.009		0.51 (0.12, 2.17)			0.359		0.31 (0.13, 0.76)	0.011
P for trend			0.021*					0.619			0.016*

Notes: Model 1: unadjusted. Versus the group of Low PA, *P<0.05. Model 2: adjusted for gender, age, BMI, smoke, alcohol use, tea drinking, sleep duration, education, dietary pattern, marital status, serum uric acid, total cholesterol, low-density lipoprotein cholesterol and sitting time. Versus the group of Low PA, *P<0.05. Variables with statistical significance are shown in boldface.

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

Table 5 Odds Ratio for the MetS and Its Components Depending on Sitting Time (or, 95% CI)

ST h/day	Total		Non-Central Obesity		Central Obesity
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
Model1 unadjusted
Metabolic syndrome
≤3	1.00		1.00		1.00
3–6	1.28 (0.85, 1.93)	0.244	0.94 (0.32, 2.73)	0.909	1.86 (1.12, 3.07)	0.016
>6	1.79 (1.16, 2.75)	0.008	2.31 (0.86, 6.23)	0.097	1.87 (1.10, 3.18)	0.020
P for trend		0.030*		0.124		0.022*
Abdominal WC
≤3	1.00		1.00		1.00
3–6	0.88 (0.60, 1.30)	0.529	1.92 (0.57, 6.46)	0.294	0.98 (0.61, 1.59)	0.942
>6	0.86 (0.56, 1.33)	0.496	2.39 (0.66, 8.63)	0.184	0.70 (0.41, 1.18)	0.177
P for trend		0.737		0.398		0.353
Increased glucose concentration
≤3	1.00		1.00		1.00
3–6	0.67 (0.46, 0.97)	0.035	0.52 (0.30, 0.91)	0.022	0.94 (0.56, 1.56)	0.799
>6	0.79 (0.53, 1.18)	0.254	0.79 (0.44, 1.42)	0.421	0.79 (0.45, 1.38)	0.412
P for trend		0.102		0.071		0.712
Elevated blood pressure
≤3	1.00		1.00		1.00
3–6	0.77 (0.57, 1.03)	0.076	0.82 (0.56, 1.20)	0.307	0.81 (0.49, 1.36)	0.428
>6	0.90 (0.65, 1.25)	0.536	0.78 (0.50, 1.21)	0.266	1.12 (0.64, 1.97)	0.698
P for trend		0.203		0.452		0.534
Increased TG concentration
≤3	1.00		1.00		1.00
3–6	1.33 (0.96, 1.84)	0.083	0.93 (0.56, 1.54)	0.778	2.45 (1.51, 3.95)	0.000
>6	1.73 (1.22, 2.46)	0.002	1.33 (0.78, 2.28)	0.298	2.39 (1.44, 3.97)	0.001
P for trend		0.009*		0.399		0.000*
Decreased HDL-C concentration
≤3	1.00		1.00		1.00
3–6	1.79 (1.04, 3.08)	0.036	2.93 (0.93, 9.23)	0.066	1.84 (0.96, 3.53)	0.065
>6	2.01 (1.13, 3.58)	0.018	3.67 (1.11, 12.16)	0.034	1.69 (0.85, 3.37)	0.138
P for trend		0.039*		0.094		0.150
Model2 adjusted
Metabolic syndrome
≤3	1.00		1.00		1.00
3–6	1.78 (1.06, 2.99)	0.029	0.99 (0.31, 3.11)	0.982	2.24 (1.22, 4.13)	0.010
>6	2.96 (1.69, 5.19)	0.000	2.79 (0.89, 8.70)	0.077	3.09 (1.55, 6.14)	0.001
P for trend		0.001*		0.105		0.003*
Abdominal WC
≤3	1.00		1.00		1.00
3–6	1.32 (0.75, 2.32)	0.338	8.11 (1.19, 55.18)	0.032	1.29 (0.67, 2.50)	0.451
>6	1.33 (0.70, 2.54)	0.380	8.45 (1.13, 63.50)	0.038	1.19 (0.56, 2.54)	0.648
P for trend		0.559		0.078		0.745
Increased glucose concentration
≤3	1.00		1.00		1.00
3–6	0.76 (0.51, 1.13)	0.179	0.58 (0.32, 1.06)	0.075	0.91 (0.52, 1.60)	0.741
>6	1.03 (0.66, 1.60)	0.910	1.09 (0.57, 2.09)	0.800	0.92 (0.49, 1.75)	0.809
P for trend		0.310		0.119		0.941
Elevated blood pressure
≤3	1.00		1.00		1.00
3–6	0.87 (0.63, 1.20)	0.394	0.86 (0.57, 1.31)	0.485	0.82 (0.47, 1.45)	0.495
>6	1.09 (0.75, 1.58)	0.658	0.88 (0.54, 1.43)	0.610	1.36 (0.71, 2.57)	0.353
P for trend		0.451		0.766		0.315
Increased TG concentration
≤3	1.00		1.00		1.00
3–6	1.56 (1.06, 2.30)	0.024	0.88 (0.50, 1.55)	0.652	2.65 (1.51, 4.63)	0.001
>6	2.07 (1.34, 3.20)	0.001	1.23 (0.65, 2.33)	0.520	2.92 (1.55, 5.47)	0.001
P for trend		0.003*		0.563		0.000*
Decreased HDL-C concentration
≤3	1.00		1.00		1.00
3–6	1.46 (0.79, 2.67)	0.225	2.14 (0.62, 7.37)	0.229	1.15 (0.55, 2.42)	0.705
>6	1.40 (0.73, 2.71)	0.312	2.58 (0.70, 9.60)	0.157	0.86 (0.38, 1.96)	0.727
P for trend		0.442		0.349		0.761

Notes: Model 1: unadjusted. Versus the group with ST of ≤ 3 h/day, *P<0.05. Model 2: adjusted for gender, age, BMI, smoke, alcohol use, tea drinking, sleep duration, education, dietary pattern, marital status, serum uric acid, total cholesterol, low-density lipoprotein cholesterol and physical activity. Versus the group with ST of ≤3 h/day, *P<0.05. Variables with statistical significance are shown in boldface.

Prevention D, Treatment of Clinical Guidelines Writing Group. 中国老年2型糖尿病防治临床指南 (2022年版) [Clinical guidelines for prevention and treatment of type 2 diabetes mellitus in the elderly in China (2022 edition)]. Zhonghua Nei Ke Za Zhi. 2022;61(1):12–50. Chinese. doi:10.3760/cma.j.cn112138-20211027-00751

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Data Sharing Statement

The datasets are not publicly available due institution’s policy but are available from the corresponding author upon reasonable request.