Prevalence and associated factors of metabolic syndrome in Chinese middle-aged and elderly population: a national cross-sectional study

Figures & data

Figure 1. Flowchart of data cleansing. HDL: high-density lipoprotein.

Table 1. Baseline population characteristics and prevalence in the grouped population.

Characteristics	Total participants (%)	IDF			NCEP-ATP ΙΙΙ
		Cases	Prevalence (%)	95% CI	Cases	Prevalence (%)	95% CI
Total	10834 (100.00)	3572	32.97	32.09-33.86	3223	29.75	28.90-30.62
Age groups
40–50	2202 (22.32)	600	27.25	25.43–29.15	491	22.30	20.61–24.09
50–60	3472 (32.05)	1196	34.45	32.88–36.05	1057	30.44	28.93–32.00
60–70	3459 (31.93)	1225	35.41	33.84–37.03	1137	32.87	31.32–34.46
>70	1701 (15.70)	551	32.39	30.21–34.66	538	31.63	29.46–33.88
Gender
Male	4977 (45.94)	1107	22.24	21.11–23.42	1035	20.80	19.69–21.95
Female	5857 (54.06)	2465	42.09	40.83–43.36	2188	37.36	36.13–38.60
Marital status
Married/cohabitated	9002 (83.09)	2931	32.56	31.60–33.53	2637	29.29	28.36–30.24
Others	1832 (16.91)	641	34.99	32.84–37.21	586	31.99	29.89–34.16
Depression
<10	6595 (66.77)	2142	32.48	31.36–33.62	1869	28.34	27.26–29.44
≥10	3282 (33.23)	1099	33.49	31.89–35.12	1038	31.63	30.06–33.24
Sleeping time
0–6 h	5292 (50.32)	1704	32.20	30.95–33.47	1548	29.25	28.04–30.49
6–8 h	4204 (39.98)	1415	33.66	32.24–35.10	1258	29.92	28.56–31.33
>8 h	1020 (9.70)	340	33.33	30.50–36.29	308	30.20	27.45–33.09
Geographical region
Urban	2629 (24.69)	1092	41.54	39.67–43.43	971	36.93	35.11–38.80
Rural	8018 (75.31)	2426	30.26	29.26–31.27	2201	27.45	26.48–28.44
Smoking
Yes	2937 (27.14)	609	20.74	19.30–22.24	589	20.05	18.64–21.54
No	6504 (60.11)	2545	39.13	37.95–40.32	2254	34.66	33.51–35.82
Quitted	1380 (12.75)	417	30.22	27.85–32.70	378	27.39	25.10–29.81
Alcohol consumption
Never	6998 (64.66)	2577	36.82	35.70–37.96	2371	33.88	32.78–35.00
Less than once a month	965 (8.92)	285	29.53	26.73–32.50	262	27.15	24.43–30.05
More than once a month	2859 (26.42)	707	24.73	23.18–26.34	588	20.57	19.12–22.09
Afternoon napping (minutes)
0	4371 (41.27)	1317	30.13	28.79–31.51	1169	26.74	25.45–28.08
1–30	1649 (15.57)	584	35.42	33.14–37.76	539	32.69	30.46–34.99
31–60	2565 (24.22)	877	34.19	32.38–36.05	787	30.68	28.93–32.50
61–90	527 (4.98)	189	35.86	31.87–40.07	172	32.64	28.76–36.77
>90	1478 (13.96)	525	35.52	33.12–38.00	475	32.14	29.80–34.57
Uric acid
Hyperuricemia	1241 (11.45)	639	51.49	48.70–54.27	613	49.40	46.61–52.18
Non-hyperuricemia	9593 (88.55)	2933	30.57	29.66–31.50	2610	27.21	26.33–28.11
Low-density lipoprotein
≥120 mg/dl	2673 (24.67)	977	36.55	34.74–38.40	866	32.40	30.65–34.20
<120 mg/dl	8160 (75.33)	2595	31.80	30.80–32.82	2357	28.88	27.91–29.88
Total cholesterol
≥200 mg/dl	3183 (29.38)	1316	41.34	39.64–43.07	1189	37.35	35.69–39.05
<200 mg/dl	7651 (70.62)	2256	29.49	28.47–30.52	2034	26.58	25.61–27.59
Body mass index, (BMI)
18.5 kg/m^2	600 (5.55)	11	1.83	1.02–3.29	38	6.33	4.64–8.59
<24 kg/m^2	5096 (47.14)	691	13.56	12.65–14.53	724	14.21	13.28–15.19
<28 kg/m^2	3656 (33.82)	1835	50.19	48.57–51.81	1474	40.32	38.74–41.92
≥28 kg/m^2	1459 (13.50)	1026	70.32	67.92–72.61	977	66.96	64.50–69.33
Blood urea nitrogen, (BUN)
0–20 mg/dl	9356 (86.36)	3157	33.74	32.79–34.71	3157	30.21	29.28–31.14
>20 mg/dl	1478 (13.64)	415	28.08	25.84–30.43	415	26.86	24.66–29.18
Liver diseases
Yes	428 (3.95)	158	36.92	32.46–41.61	136	29.67	28.80–30.55
No	10406 (96.05)	3414	32.81	31.91–33.72	3087	31.78	27.52–36.36
Kidney diseases
Yes	687 (6.34)	230	33.48	30.04–37.10	210	30.57	27.23–34.13
No	10147 (93.66)	3342	32.94	32.03–33.86	3013	29.69	28.81–30.59
Digestive system diseases
Yes	2463 (22.73)	771	31.30	29.50–33.16	723	29.35	27.59–31.19
No	8371 (77.27)	2801	33.46	32.46–33.48	2500	29.87	28.89–30.85
Arthritis
Yes	3589 (33.13)	1251	34.86	33.31–36.43	1168	32.54	31.03–34.10
No	7245 (66.87)	2321	32.04	30.97–33.12	2055	28.36	27.34–29.41

IDF: International Diabetes Federation; NCEP-ATP III: National Cholesterol Education Program (Adult Treatment Panel III); CI: confidence interval; BUN: blood urea nitrogen; BMI: Body Mass Index.

Figure 2. Age and gender-specific prevalence of metabolic syndrome and its components. MetS: metabolic syndrome; HDL: High-density lipoprotein.

Figure 3. Age and gender gender-specific prevalence of metabolic syndrome in urban and rural areas.

Figure 4. Gender-specific prevalence of metabolic syndrome in different regions.

Table 2. The associated factors and adjusted ORs for MetS.

Characteristics	Crude OR (95% CI)	p value	Adjusted OR (95% CI)	p value
Age group
40–50	1.00 (reference)	–	1.00 (reference)	–
50–60	1.40 (1.25–1.58)	<0.001	1.58 (1.39–1.79)	<0.001
60–70	1.46 (1.30–1.65)	<0.001	1.71 (1.50–1.95)	<0.001
>70	1.28 (1.11–1.47)	<0.001	1.52 (1.30–1.78)	<0.001
Gender
Male	1.00 (reference)	–	1.00 (reference)	–
Female	2.54 (2.33–2.76)	<0.001	2.54 (2.22–2.90)	<0.001
Marital status
Married/cohabitated	1.00 (reference)	–	1.00 (reference)	–
Others	1.11 (1.00–1.24)	<0.05	1.01 (0.90–1.14)	0.839
Depression
<10	1.00 (reference)	–	–	–
≥ 10	1.05 (0.96–1.14)	0.316	–	–
Sleeping time
0–6 h	0.94 (0.86–1.02)	0.133	–	–
6–8 h	1.00 (reference)	–	–	–
> 8 h	0.99 (0.85–1.14)	0.844	–	–
Geographical area
Urban	1.00 (reference)	–	1.00 (reference)	–
Rural	0.61 (0.56–0.67)	<0.001	0.60 (0.54–0.66)	<0.001
Smoking
Yes	0.41 (0.37–0.45)	<0.01	0.79 (0.68–0.91)	<0.01
No	1.00 (reference)	–	1.00 (reference)	–
Quitted	0.67 (0.59–0.76)	<0.001	1.24 (1.06–1.46)	<0.01
Alcohol consumption
Never	1.00 (reference)	–	1.00 (reference)	–
Less than once a month	0.71 (0.62–0.83)	<0.001	0.90 (0.80–1.01)	0.083
More than once a month	0.56 (0.51–0.62)	<0.001	0.90 (0.77–1.05)	0.188
Afternoon nap (minutes)
0	1.00 (reference)	–	1.00 (reference)	–
1–30	1.27 (1.13–1.43)	<0.001	1.31 (1.16–1.49)	<0.001
31–60	1.20 (1.09–1.34)	<0.001	1.38 (1.23–1.54)	<0.001
61–90	1.30 (1.07–1.57)	<0.01	1.61 (1.32–1.97)	<0.001
> 90	1.28 (1.13–1.45)	<0.001	1.54 (1.35–1.76)	<0.001
Blood urea nitrogen (BUN)
0–20 mg/dl	1.00 (reference)	–	1.00 (reference)	–
> 20 mg/dl	0.77 (0.68–0.87)	<0.001	0.82 (0.72–0.94)	<0.01
Liver disease
Yes	1.20 (0.98–1.46)	0.077	–	–
No	1.00 (reference)	–	–	–
Kidney diseases
Yes	1.02 (0.87–1.21)	0.770	–	–
No	1.00 (reference)	–	–	–
Digestive system diseases
Yes	0.91 (0.82–1.00)	<0.05	0.83 (0.75–0.92)	0.745
No	1.00 (reference)	–	1.00 (reference)	–
Arthritis
Yes	1.14 (1.04–1.24)	<0.01	1.08 (0.98–1.19)	0.102
No	1.00 (reference)	–	1.00 (reference)	–

Logistic regression was adopted to identify the independent associated factors of MetS. All plausible variables with p < 0.05 in univariate testing were subjected to further multivariate testing. The crude ORs were calculated in univariate regression and the adjusted ORs were recorded using multivariate regression. OR: Odds Ratio; CI: confidence interval; BUN: blood urea nitrogen.

Data availability statement

The data that support the findings of this study are available from China Health and Retirement Longitudinal Study (CHARLS) website (http://charls.pku.edu.cn/). The full datasets used in this analysis are available from the corresponding author upon reasonable request.