Baseline characteristics of elderly by MetS status
Demographic data for the 2869 elderly at baseline in 2012–2013 were presented in Table 1. Elderly with MetS had significantly higher rate of female (66.6% vs. 38.3%), light physical activity (63.9% vs. 55.2%), family history of hypertension (24.2% vs. 16.1%), CHD (14.1% vs. 10.2%) and Stroke (20.9% vs. 15.9%) compared with those without MetS. As for biochemical parameters, elderly with MetS had significantly higher value of SBP, DBP, BMI, WC, TG, LDL-C, HDL-C, and FPG.
Table 1
Baseline characteristics of rural Northeast Chinese elderly by MetS status.
Variables | Total (n = 2869) | Non-MetS (n = 1565) | MetS (n = 1304) | P-value |
Man | 1401(48.8) | 965(61.7) | 436(33.4) | < 0.001 |
Age (years) | 66.91 ± 5.72 | 67.01 ± 5.86 | 66.79 ± 5.56 | 0.308 |
Ethnicity | | | | 0.279 |
Han | 2742(95.6) | 1492(95.3) | 1250(95.9) | |
Others a | 127(4.4) | 73(4.7) | 54(4.1) | |
Education status | | | | 0.052 |
Primary school or below | 2161(75.3) | 1152(73.6) | 1009(77.4) | |
Middle school | 582(20.3) | 343(21.9) | 239(18.3) | |
High school or above | 126(4.4) | 70(4.5) | 56(4.3) | |
Physical activity | | | | < 0.001 |
Light | 1679(59.2) | 856(55.2) | 823(63.9) | |
Moderate | 455(16.0) | 247(15.9) | 208(16.2) | |
Severe | 703(24.8) | 447(28.8) | 256(19.9) | |
Annual income (CNY/year) | | | | 0.099 |
≤ 5000 | 677(23.6) | 389(24.9) | 288(22.1) | |
5000–20000 | 1614(56.3) | 878(56.2) | 736(56.5) | |
> 20000 | 574(20.0) | 295(18.9) | 279(21.4) | |
Current smoking status (Yes) | 1019(35.5) | 673(43.0) | 346(26.5) | < 0.001 |
Current drinking status (Yes) | 580(20.2) | 419(26.8) | 161(12.3) | < 0.001 |
Family history of hypertension | 567(19.8) | 252(16.1) | 315(24.2) | < 0.001 |
Family history of CHD | 344(12.0) | 160(10.2) | 184(14.1) | 0.001 |
Family history of Stroke | 522(18.2) | 249(15.9) | 273(20.9) | < 0.001 |
SBP (mmHg) | 152.66 ± 24.54 | 148.03 ± 24.09 | 158.21 ± 23.91 | < 0.001 |
DBP (mmHg) | 82.27 ± 11.71 | 80.41 ± 11.40 | 84.49 ± 11.71 | < 0.001 |
BMI (kg/m2) | 24.46 ± 3.72 | 22.92 ± 3.24 | 26.30 ± 3.40 | < 0.001 |
WC (cm) | 82.89 ± 10.06 | 78.22 ± 8.61 | 88.48 ± 8.74 | < 0.001 |
TG (mmol/L) | 1.64 ± 1.35 | 1.12 ± 0.60 | 2.26 ± 1.70 | < 0.001 |
LDL-C(mmol/L) | 3.11 ± 0.87 | 2.96 ± 0.80 | 3.30 ± 0.92 | < 0.001 |
HDL-C (mmol/L) | 1.43 ± 0.40 | 1.57 ± 0.41 | 1.26 ± 0.31 | < 0.001 |
FPG (mmol/L) | 6.10 ± 1.81 | 5.65 ± 1.25 | 6.64 ± 2.19 | < 0.001 |
Data are expressed as the mean ± SD or as n (%). Abbreviations: BMI body mass index, WC waist circumference, CNY China Yuan (1CNY = 0.161 USD), SBP systolic blood pressure, DBP diastolic blood pressure, TC total cholesterol, TG triglyceride, LDL-C low-density lipoprotein cholesterol, HDL-C high-density lipoprotein cholesterol, FPG fasting plasma glucose. a Including some ethnic minorities in China, such as Mongol and Manchu. |
Changes of biochemical parameters from baseline to follow-up in elderly with or without MetS
At baseline, 1304 elderly were diagnosed MetS. We intend to estimate the changes of metabolic parameters like SBP, DBP, WC, BMI and biochemical parameters in the past years among elderly with or without MetS. Data was shown in Fig. 1. From 2012–2013 to 2015–2017 year, SBP, DBP, BMI, FPG, and HDL-C significantly decreased among elderly with MetS whereas WC increased apparently. Similarly, among elderly without MetS at baseline, SBP, DBP, and HDL-C increased from 2012–2013 to 2015–2017 year. However, WC, FPG, TG and LDL-C increased as time passed among elderly without MetS. There were differences in the changes of biochemical parameters among participants with or without MetS.
The possible predictors of CVEs among elderly with MetS at baseline
In order to figure out the possible predictors of CVEs among elderly with MetS, we conducted the Cox’s proportional-hazard analysis. In Table 2, we can see that family history of hypertension (HR = 1.694, 95%CI = 1.121, 2.560, P = 0.012), current smoking status at baseline (HR = 1.518, 95%CI = 1.020, 2.259, P = 0.040), per 1 mmHg increase of SBP (HR = 1.016, 95%CI = 1.006, 1.025, P = 0.001), and per 1 mmol/L increase of HDL-C (HR = 0.365, 95%CI = 0.164, 0.811, P = 0.013) were all correlated with CVEs among elderly with MetS.
Table 2
Cox proportional hazards model: Hazard ratio of newly onset cardiovascular events among elderly with MetS at baseline (n = 1059).
Variable | Hazard ratio | HR lower CL | HR upper CL | P-value |
Age at entry (per 1 year) | 1.026 | 0.992 | 1.062 | 0.134 |
Gender (male as refer) | 1.269 | 0.813 | 1.981 | 0.295 |
Race (minority as refer) | 0.562 | 0.262 | 1.206 | 0.139 |
Family history of CHD (no as refer) | 0.996 | 0.572 | 1.735 | 0.989 |
Family history of Stroke (no as refer) | 1.268 | 0.815 | 1.973 | 0.292 |
Family history of Hypertension (no as refer) | 1.694 | 1.121 | 2.560 | 0.012 |
SBP (per 1 mmHg) | 1.016 | 1.006 | 1.025 | 0.001 |
DBP (per 1 mmHg) | 0.999 | 0.980 | 1.019 | 0.945 |
BMI (per 1 kg/m2) | 1.012 | 0.957 | 1.070 | 0.681 |
FPG (per 1 mmol/L) | 0.985 | 0.910 | 1.067 | 0.717 |
TG (per 1 mmol/L) | 0.843 | 0.699 | 1.015 | 0.071 |
HDL-C (per 1 mmol/L) | 0.365 | 0.164 | 0.811 | 0.013 |
LDL-C (per 1 mmol/L) | 0.830 | 0.537 | 1.282 | 0.402 |
Sleep duration (≤ 7 hour/day as refer) | | | | |
7–8 hour/day | 1.085 | 0.682 | 1.728 | 0.729 |
8–9 hour/day | 1.108 | 0.639 | 1.921 | 0.714 |
>9 hour/day | 1.412 | 0.754 | 2.645 | 0.281 |
Education status (Primary school or below as refer) | | | | |
Middle school | 0.781 | 0.469 | 1.300 | 0.342 |
High school or above | 0.810 | 0.315 | 2.085 | 0.662 |
Annual income (CNY/year)(≤ 5000 as refer) | | | | |
5000–20000 | 0.712 | 0.460 | 1.103 | 0.129 |
> 20000 | 0.667 | 0.388 | 1.148 | 0.144 |
Physical activity (Light as refer) | | | | |
Moderate | 1.003 | 0.622 | 1.618 | 0.990 |
Heavy | 0.743 | 0.435 | 1.269 | 0.277 |
Current smoking (no as refer) | 1.518 | 1.020 | 2.259 | 0.040 |
Current drinking (no as refer) | 1.349 | 0.776 | 2.346 | 0.289 |
HDL-C: high-density lipoprotein cholesterol; LDL-C: low-density lipoprotein cholesterol; TG: triglyceride; TC: total cholesterol; |
Cumulative incidence of newly diagnosed MetS among elderly
In the present study, 1565 elderly were without MetS at baseline. During 4.66 years of follow-up, the cumulative incidence of newly diagnosed MetS among this 1565 elderly was shown in Figure 2. Female had significantly higher rate of MetS compared to men (36.3% vs. 24.4%, P<0.001) (Figure 2A). As shown in Figure 2B, with the increase numbers of metabolic disorders, the rate of newly diagnosed MetS also increased (14.0%, 21.2% and 36.7%, P for trend<0.001). If elderly had metabolic disorders at baseline, they were more likely to develop MetS during follow-up (Figure 2C). Elderly with abdominal obesity (44.3% vs. 26.2%, P<0.001), elevated BP (30.5% vs. 22.9%, P=0.008), high TG (47.6% vs. 26.9%, P<0.001), and low HDL-C (39.0% vs. 28.0%, P<0.001) had significantly higher rate of newly diagnosed MetS compared with subjects without them. The highest rate of newly diagnosed MetS was among elderly with high TG (47.6%)
Possible associated factors of newly diagnosed MetS
In order to estimate the possible risk factors that might affect the incidence of MetS, we conducted the multivariable analysis (Table 3). Data showed that male gender (OR=0.390, 95%CI=0.272, 0.560, P<0.001), per 1 unit increase of SBP (OR=1.013, 95%CI=1.005, 1.022, P=0.002), BMI (OR=1.178, 95%CI=1.120, 1.239, P<0.001), FPG (OR=1.256, 95%CI=1.111, 1.420, P<0.001), TG (OR= 1.975, 95%CI=1.438, 2.712, P<0.001), HDL-C (OR=0.536, 95%CI=0.323, 0.890, P=0.016) and LDL-C (OR= 2.047, 95%CI=1.342, 3.124, P=0.001) at baseline and 8-9 hours/day sleep duration (OR=0.580, 95%CI=0.367, 0.917, P=0.020) were associated with incidence of MetS among elderly.
Table 3. Multivariable analysis of possible association between risk factors and cumulative incidence of MetS among elderly without MetS at baseline (n=1565).
|
Variable
|
Odd ratio
|
95%CI
(lower)
|
95%CI
(Upper)
|
P-value
|
Age at entry (per 1 year)
|
0.989
|
0.961
|
1.017
|
0.436
|
Gender (female as refer)
|
0.390
|
0.272
|
0.560
|
<0.001
|
Race (minority as refer)
|
1.088
|
0.552
|
2.145
|
0.807
|
SBP (per 1 mmHg)
|
1.013
|
1.005
|
1.022
|
0.002
|
DBP (per 1 mmHg)
|
1.000
|
0.983
|
1.016
|
0.959
|
BMI (per 1kg/m2)
|
1.178
|
1.120
|
1.239
|
<0.001
|
FPG (per 1 mmol/L)
|
1.256
|
1.111
|
1.420
|
<0.001
|
TG (per 1 mmol/L)
|
1.975
|
1.438
|
2.712
|
<0.001
|
HDL-C (per 1 mmol/L)
|
0.536
|
0.323
|
0.890
|
0.016
|
LDL-C (per 1 mmol/L)
|
2.047
|
1.342
|
3.124
|
0.001
|
Sleep duration (≤7 hour/day)
|
|
|
|
|
7-8 hour/day
|
0.859
|
0.613
|
1.204
|
0.378
|
8-9 hour/day
|
0.580
|
0.367
|
0.917
|
0.020
|
>9 hour/day
|
0.927
|
0.527
|
1.628
|
0.791
|
Education status (Primary school or below as refer)
|
|
|
|
|
Middle school
|
1.215
|
0.863
|
1.711
|
0.265
|
High school or above
|
0.919
|
0.426
|
1.982
|
0.829
|
Annual income (CNY/year)( ≤ 5000 as refer)
|
|
|
|
|
5000-20000
|
0.809
|
0.572
|
1.145
|
0.232
|
> 20000
|
0.711
|
0.453
|
1.118
|
0.140
|
Physical activity (Light as refer)
|
|
|
|
|
Moderate
|
0.857
|
0.573
|
1.280
|
0.450
|
Heavy
|
1.220
|
0.871
|
1.709
|
0.248
|
Family history of hypertension (no as refer)
|
1.101
|
0.749
|
1.619
|
0.625
|
Family history of CHD (no as refer)
|
0.786
|
0.491
|
1.257
|
0.315
|
Family history of Stroke (no as refer)
|
1.249
|
0.852
|
1.830
|
0.254
|
Current smoking (no as refer)
|
1.355
|
0.990
|
1.853
|
0.057
|
Current drinking (no as refer)
|
1.107
|
0.766
|
1.601
|
0.588
|
HDL-C: high-density lipoprotein cholesterol; LDL-C: low-density lipoprotein cholesterol; TG: triglyceride; TC: total cholesterol;
|