# Analysis of Association of Occupational Physical Activity, Leisure-Time Physical Activity, and Sedentary Lifestyle with Hypertension according to the Adherence with Aerobic Activity in Women Using Korea National Health and Nutrition Examination Survey 2016-2017 Data

Authors: Mikyung Ryu; Sol Lee; Ho Gym; Weon-Chil Baek; Heejin Kimm
Journal: International Journal of Hypertension
 (2020)

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## Abstract

Purpose. We investigated the association between occupational physical activity, leisure-time physical activity, and sedentary lifestyle with hypertension by adherence with aerobic exercise in middle-aged and elderly women. Methods. A cross-sectional analysis was performed using Korea National Health and Nutrition Examination Survey (KNHANES), a nationally representative data between 2016 and 2017. A total of 4,241 women aged 40 years or older were included. Hypertension diagnosed by physician and exercise status was asked by questionnaires. Results. Mean age of the participants was 58.4 (±11.4, range: 40∼80 years). There were 1,681 (39.6%) women in the aerobic activity adherence group. In the logistic regression analysis with adjustment for confounding factors, frequency of occupational physical activity (OPA) level (OR 1.931; p=0.048, in ≤4 per week group), walking frequency (OR 0.436; p=0.001, in 5∼7 days per week walking group compared with never walking group) in the aerobic activity adherence group, sitting hours (OR 1.849; 95% CI: 1.279–2.673, p=0.001, in 13 hours or longer group compared with 6 hours or less sitting hours group), and muscle strengthening exercises (OR 0.554; 95% CI: 0.353–0.870, p=0.010, 1∼4 days per week compared with never) in the nonadherence group were significantly associated with hypertension. Conclusions. In the aerobic activity adherence group, further research is needed to identify the influence of occupational physical activity. In the aerobic activity nonadherence group, decreasing sitting hours and increasing endurance exercise may be helpful.


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## Body

## 1. Introduction

Hypertension has been a well-known condition causing cardiovascular disease, stroke, and chronic kidney disease [1–3], leading to premature mortality and finally death if not detected and treated within the appropriate period [4]. Hypertension is also a worldwide important public health issue and epidemiological matter [5]. Moreover, it has been reported that health-related quality of life is lower in people with diagnosed hypertension than those without diagnosed hypertension [6]. Moreover, the estimated number of adults with hypertension has increased over the years from 594 million in 1975 to 1.13 billion in 2015 [7]. Physical activity is known to be associated with decreased incidence of hypertension. It has showed benefits on blood pressure not only in people with normal blood pressure but also in patients with prehypertension or hypertension [8].Physical training, particularly aerobic exercises, is recommended as an antihypertensive solution leading to significant blood pressure, body weight, body fat, and waist circumference reduction, along with insulin sensitivity and HDL cholesterol level improvement [9, 10]. Also, regular aerobic training has been reported to reduce blood pressure in both younger and older people with hypertension by decreasing aortic stiffness and enhanced flow-mediated arterial dilation mediated by increased nitric oxide released from endothelial cells lining these blood vessels, similar to blood pressure reductions by a single antihypertensive drug [11]. In previous studies, regular physical training such as walking, jogging, or swimming for 30 to 45 minutes can reduce blood pressure and is recommended by current American and European hypertension guidelines [12, 13]. These were leisure-time physical activity, which consistently showed a positive effect on cardiovascular outcomes, including hypertension [14, 15]. The negative consequences of sedentary lifestyles are also well established [16].However, despite the obvious reduction of cardiovascular mortality in other reports [15], there has been controversy among studies on the effects of occupational physical activity due to the risk of anaerobic components or injuries, depending on the nature of the work [14, 17]. Few studies explored the association of occupational, leisure-time, and sedentary activities with hypertension diagnosed by physician in middle-aged and elderly women. It is unclear whether this association depends on the adherence with aerobic activity.The aim of this study is to examine the association of occupational physical activity, leisure-time physical activity, and sedentary lifestyle with hypertension according to the adherence with aerobic exercise in a nationally representative sample of women over 40 years of age, using recent Korea National Health and Nutrition Examination Survey (KNHANES) Data.


## 2. Methods

### 2.1. Participants

In this study, a cross-sectional analysis was performed using the Korea National Health and Nutrition Examination Survey (KNHANES) data collected by the Korea Centers for Disease Control and Prevention (KCDC) from 2016 to 2017. KNHANES is a surveillance system to assess the health and nutritional status of population in the Republic of Korea.KNHANES includes a health interview, health examination, and nutrition survey. The interview and examination are performed by trained medical staff and interviewers. A multistage stratified cluster sampling was done for the household unit selection. The Institutional Review Board of the KCDC approved the data collection with written informed consent forms from all participants. The details of the survey design and data resource were described on a profiles paper in 2014 [18]. In this study, women participants older than 40 years of age who completed both answers on hypertension diagnosis (yes or no) and aerobic activities (yes or no) were included (n = 4,241).


### 2.2. Variables

Hypertension was defined as “participants’ answer on hypertension diagnosed by medical doctor” from health survey questionnaires. Participants with no response were excluded from the analysis. If the participants answered “yes” to the questions for moderate intensity physical activity (at least 2.5 hours per week) or “yes” for vigorous intensity physical activity (at least 1.5 hours per week), they were classified as “aerobic activity adherence group.” Those who failed to be classified as the adherence group were categorized as “nonadherence group.” If the participants answered “yes” to the questions for muscle strengthening exercises (MSE) such as push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days for the past week, they were classified as “adherence group.”Sociodemographic characteristics including age, quartiles of equivalent income, and education (less than elementary school, less than middle school, less than high school, and more than university graduation) were included in the questionnaires. Smoking status was classified as never smoker, former smoker, or current smoker, and alcohol consumption was divided into 4 categories (never, no drink within recent 1 year, less than 4 times drink per a month, or more than 5 times per month). Sleeping hours were classified as 7 hours of sleep per day in weekdays as well as in weekends, respectively. For physical activities, each of vigorous or moderate intensity physical activity group was divided into two aspects, work (occupational physical activity, OPA) and leisure (leisure-time physical activity, LPA), with 3 subcategories (never, ≤4 days per week, or 5∼7 days per week), respectively. Sitting hours were classified as ≤6, 7∼12, or ≥13 hours per a day. Frequency of walking per week was divided into 3 categories (never, ≤4 days per week, or 5∼7 days per week).


### 2.3. Statistical Analysis

The data were expressed by numbers and percentages for describing the general characteristics of the study participants. The frequency in the adherence group and the nonadherence group was compared by the chi-square test. To determine the difference for clinical variables in each group, independent two-samplet-test was done. Odds ratios (ORs) and 95% confidence intervals (CIs) using binomial logistic regression were obtained to analyze an association between physical activity and hypertension in women with adjustment for other covariates. A p value less than 0.05 was used for statistical significance. IBM SPSS statistics 22.0 software (IBM Corp, Armonk, NY) was used.


## 2.1. Participants

In this study, a cross-sectional analysis was performed using the Korea National Health and Nutrition Examination Survey (KNHANES) data collected by the Korea Centers for Disease Control and Prevention (KCDC) from 2016 to 2017. KNHANES is a surveillance system to assess the health and nutritional status of population in the Republic of Korea.KNHANES includes a health interview, health examination, and nutrition survey. The interview and examination are performed by trained medical staff and interviewers. A multistage stratified cluster sampling was done for the household unit selection. The Institutional Review Board of the KCDC approved the data collection with written informed consent forms from all participants. The details of the survey design and data resource were described on a profiles paper in 2014 [18]. In this study, women participants older than 40 years of age who completed both answers on hypertension diagnosis (yes or no) and aerobic activities (yes or no) were included (n = 4,241).


## 2.2. Variables

Hypertension was defined as “participants’ answer on hypertension diagnosed by medical doctor” from health survey questionnaires. Participants with no response were excluded from the analysis. If the participants answered “yes” to the questions for moderate intensity physical activity (at least 2.5 hours per week) or “yes” for vigorous intensity physical activity (at least 1.5 hours per week), they were classified as “aerobic activity adherence group.” Those who failed to be classified as the adherence group were categorized as “nonadherence group.” If the participants answered “yes” to the questions for muscle strengthening exercises (MSE) such as push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days for the past week, they were classified as “adherence group.”Sociodemographic characteristics including age, quartiles of equivalent income, and education (less than elementary school, less than middle school, less than high school, and more than university graduation) were included in the questionnaires. Smoking status was classified as never smoker, former smoker, or current smoker, and alcohol consumption was divided into 4 categories (never, no drink within recent 1 year, less than 4 times drink per a month, or more than 5 times per month). Sleeping hours were classified as 7 hours of sleep per day in weekdays as well as in weekends, respectively. For physical activities, each of vigorous or moderate intensity physical activity group was divided into two aspects, work (occupational physical activity, OPA) and leisure (leisure-time physical activity, LPA), with 3 subcategories (never, ≤4 days per week, or 5∼7 days per week), respectively. Sitting hours were classified as ≤6, 7∼12, or ≥13 hours per a day. Frequency of walking per week was divided into 3 categories (never, ≤4 days per week, or 5∼7 days per week).


## 2.3. Statistical Analysis

The data were expressed by numbers and percentages for describing the general characteristics of the study participants. The frequency in the adherence group and the nonadherence group was compared by the chi-square test. To determine the difference for clinical variables in each group, independent two-samplet-test was done. Odds ratios (ORs) and 95% confidence intervals (CIs) using binomial logistic regression were obtained to analyze an association between physical activity and hypertension in women with adjustment for other covariates. A p value less than 0.05 was used for statistical significance. IBM SPSS statistics 22.0 software (IBM Corp, Armonk, NY) was used.


## 3. Results

### 3.1. General Characteristics of Study Population

The mean age of the 4,241 women participants from KNHANES 2016-2017 data was 58.4 (±11.4, range: 40–80 years old). Among them, 29.1% (1,234) of participants had hypertension and 92.7% were never smokers. There were 1,681 (39.6%) women in the aerobic activity adherence group and 2,560 (60.4%) participants were in the nonadherence group. For muscle strengthening exercises adherence, 3,560 (83.9%) participants never did the exercise, 465 (11.0%) did 1–4 day per week, and 215 (5.1%) did more than 5 days per week. Most participants reported no vigorous intensity physical activity for both occupation (99.5%) and leisure time (94.6%). There was a similar trend for moderate intensity physical activity (Table1).Table 1
Characteristics of the women participated in this study.
Items
n
%
Age (years)
40–49 y
1148
27.1
50–59 y
1210
28.5
60–69 y
1042
24.6
≥70 y
841
19.8
Income level
Level 1
940
22.2
Level 2
1061
25.0
Level 3
1091
25.7
Level 4
1142
26.9
Education level
Elementary
1355
32.0
Middle
568
13.4
High
1276
30.1
University
1036
24.4
Hypertension
No
3007
70.9
Yes
1234
29.1
Aerobic activity adherencea (per week)
No
2560
60.4
Yes
1681
39.6
Muscle strengthening exercises adherenceb (per week)
Never
3560
83.9
≤4
465
11.0
5∼7 days
215
5.1
OPA vigorous intensity (per week)
Never
4219
99.5
≤4
12
0.3
5∼7 days
10
0.2
OPA moderate intensity (per week)
Never
4061
95.8
≤4
108
2.5
5∼7 days
72
1.7
Physical activity days with moving location (per week)
Never
1801
42.5
≤4
1101
26.0
5∼7 days
1339
31.6
LPA vigorous intensity (per week)
Never
4011
94.6
≤4
162
3.8
5∼7 days
68
1.6
LPA moderate intensity (per week)
Never
3436
81.0
≤4
577
13.6
5∼7 days
228
5.4
Sitting hours (per day)
≤6 hours
1831
43.2
≤12 hours
2028
47.8
≥13 hours
382
9.0
Walking (days per week)
Never
823
19.4
≤4 days
1578
37.2
≥5 days
1838
43.3
Sleeping hours in weekdays (per week)
<7 hours
2594
61.2
≥7 hours
1647
38.8
Sleeping hours in weekends (per week)
<7 hours
1989
46.9
≥7 hours
2252
53.1
Alcohol consumption (within 1 year)
No experience
884
20.8
No drink within recent 1 year
834
19.7
≤4 times (months)
2147
50.6
≥5 times (months)
376
8.9
Smoking status
Never
3933
92.7
Former smoker
162
3.8
Current smoker
145
3.4
aAerobic activity adherence: 2.5-hour moderate intensity physical activity per week or 1.25-hour vigorous intensity physical activity per week. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OPA: occupational physical activity; LPA: leisure-time physical activity.


### 3.2. General Characteristics and Physical Activity Status due to Aerobic Activity Adherence

Aerobic activity adherence showed a significant association with age groups (40–49, 50–59, 60–69, and more than 70 years) (Table2). Quartiles of equivalent income and education were associated with aerobic activity adherence (p<0.05), and hypertension also showed a significant association with aerobic activity adherence. OPA and LPA days per week were significantly associated with aerobic activity adherence (p<0.05). There was a significant association between aerobic activity adherence and physical activity days with moving location. Sitting hours were significantly associated with aerobic activity adherence (p<0.05). Sleeping hours per week were associated with aerobic activity adherence (p<0.05). However, no association was found between sleeping hours during weekend and aerobic activity adherence. Alcohol consumption showed significant association aerobic activity adherence (p<0.05), but smoking status showed no association.Table 2
General characteristics and physical activity status due to aerobic activity adherence.
Items
Total
Nonaerobic (n = 2,560)
Aerobic (n = 1,681)
p value
n
n
%
n
%
Age (years)
40–49 y
1148
624
24.4
524
31.2
<0.001∗∗
50–59 y
1210
660
25.8
550
32.7
60–69 y
1042
640
25.0
402
23.9
≥70 y
841
636
24.8
205
12.2
Income level
Level 1
940
611
23.9
329
19.6
<0.001∗∗
Level 2
1061
660
25.8
401
23.9
Level 3
1091
640
25.1
451
26.8
Level 4
1142
643
25.2
499
29.7
Education level
Elementary
1355
970
38.0
385
22.9
<0.001∗∗
Middle
568
351
13.7
217
12.9
High
1276
703
27.5
573
34.1
University
1036
531
20.8
505
30.1
Hypertension
No
3007
1689
66.0
1318
78.4
<0.001∗∗
Yes
1234
871
34.0
363
21.6
Aerobic activity adherencea (per week)
No
3560
2265
88.5
1295
77.0
<0.001∗∗
Yes
465
199
7.8
266
15.8
Never
215
95
3.7
120
7.1
OPA vigorous intensity (per week)
≤4 days
4219
2557
99.9
1662
98.9
<0.001∗∗
5∼7 days
12
2
0.1
10
0.6
Never
10
1
0.0
9
0.5
OPA moderate intensity (per week)
≤4 days
4061
2533
98.9
1528
90.9
<0.001∗∗
5∼7 days
108
25
1.0
83
4.9
Never
72
2
0.1
70
4.2
Physical activity days with moving location (per week)
≤4 days
1801
1592
62.2
209
12.4
<0.001∗∗
5∼7 days
1101
710
27.7
391
23.3
Never
1339
258
10.1
1081
64.3
LPA vigorous intensity (per week)
≤4 days
4011
2550
99.6
1461
86.9
<0.001∗∗
5∼7 days
162
10
0.4
152
9.0
Never
68
0
0.0
68
4.0
LPA moderate intensity (per week)
≤4 days
3436
2412
94.2
1024
60.9
<0.001∗∗
5∼7 days
577
138
5.4
439
26.1
Never
228
10
0.4
218
13.0
Sitting hours (per day)
≤6 hours
1831
1003
39.2
828
49.3
<0.001∗∗
≤12 hours
2028
1290
50.4
738
43.9
≥13 hours
382
267
10.4
115
6.8
Walking (days per week)
Never
823
731
28.6
92
5.5
<0.001∗∗
≤4 days
1578
1126
44.0
452
26.9
5∼7 days
1838
702
27.4
1136
67.6
Sleeping hours in weekdays (per week)
<7 hours
2594
1505
58.8
1089
64.8
<0.001∗∗
≥7 hours
1647
1055
41.2
592
35.2
Sleeping hours in weekends (per week)
<7 hours
1989
1189
46.4
800
47.6
0.465
≥7 hours
2252
1371
53.6
881
52.4
Alcohol consumption (within 1 year)
No experience
884
584
22.8
300
17.8
<0.001∗∗
No drink within recent 1 year
834
535
20.9
299
17.8
≤4 times (months)
2147
1210
47.3
937
55.7
≥5 times (months)
376
231
9.0
145
8.6
Smoking status
Never
3933
2357
92.1
1576
93.8
0.091
Former smoker
162
103
4.0
59
3.5
Current smoker
145
99
3.9
46
2.7
aAerobic activity adherence: 2.5-hour moderate intensity physical activity per week or 1.25-hour vigorous intensity physical activity per week. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OPA: occupational physical activity; LPA: leisure-time physical activity. ∗p<0.05; ∗∗p<0.01.


### 3.3. Comparison of Clinical Characteristics according to the Aerobic Activity Adherence

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) showed significant differences between the aerobic activity nonadherence group and aerobic activity adherence group (p<0.05). Body mass index (BMI) and HDL cholesterol showed significant differences between the two groups (p<0.05). In triglyceride, glutamate oxaloacetate transaminase (GOT), and glutamate-pyruvate transaminase (GPT) levels, there were significant differences between the two groups (p<0.05). However, total cholesterol showed no difference (Table 3).Table 3
Comparison of clinical characteristics according to the aerobic activity adherence.
Aerobic activity nonadherence group (n = 2,560)
Aerobic activity adherence group (n = 1,681)
p value
Mean
SD
Mean
SD
Mean SBP
122.05
17.73
119.25
17.42
<0.001∗∗
Mean DBP
74.58
9.51
75.17
9.32
0.048∗
BMI
24.12
3.57
23.79
3.34
0.002∗
Total cholesterol
198.51
39.27
199.82
38.15
0.294
HDL cholesterol
52.48
12.53
54.61
12.66
<0.001∗∗
Triglyceride
132.38
100.99
117.13
77.88
<0.001∗∗
AST (GOT)
22.43
9.65
21.73
8.54
0.016∗
ALT (GPT)
19.85
12.98
18.84
12.08
0.011∗
SD: standard deviation; SBP: systolic blood pressure; DBP: diastolic blood pressure; BMI: body mass index; GOT: glutamate oxaloacetate transaminase; GPT: glutamate-pyruvate transaminase.∗p<0.05; ∗∗p<0.01.


### 3.4. Association between Physical Activity and Hypertension in the Aerobic Activity Nonadherence Group

In the aerobic activity nonadherence group, the odds ratio (OR) for hypertension in muscle strengthening exercises (MSE) adherence group (1∼4 days per week) was 0.468 (95% CI: 0.322–0.681,p<0.001) in the unadjusted model and 0.554 (95% CI: 0.353–0.870) in the adjusted model with adjustment for age, quartiles of equivalent income, education levels, smoking status, and alcohol consumption, compared with the “never” group.For sitting hours, ORs for hypertension were 1.211 (95% CI: 1.008–1.455) in 7∼12 hours group and 2.275 (95% CI: 1.704–3.036) in 13 hours or longer group, compared with 6 hours or less sitting hours group in unadjusted model, respectively. They were 1.161 (95% CI: 0.929–1.451) and 1.849 (95% CI: 1.279–2.673) compared with 6 hours or less sitting hours group in the adjusted model with adjustment of age, quartiles of equivalent income, education levels, smoking status, and alcohol consumption, respectively.A significant association was found between hypertension and days of walking per week. The OR for hypertension was 0.802 (95% CI: 0.644–0.998) in ≤4 days per week group, compared with the never walking group in the unadjusted model. However, no significant association was found with hypertension after adjustment.Sleeping hours during week or weekend showed significant association with hypertension in the unadjusted model. However, the association disappeared in results from the adjusted model (Table4).Table 4
Association between physical activity and hypertension in the aerobic activity nonadherence group.
Items
Unadjusted OR
p value
Adjusteda OR
p value
Muscle strengthening exercises adherenceb (per week)
Never
<0.001∗∗
0.034∗
≤4
0.468
<0.001∗∗
0.554
0.010∗
5∼7 days
0.830
0.433
0.850
0.570
OPA vigorous intensity (per week)
Never
1.000
1.000
≤4
0.999
0.999
5∼7 days
0.000
1.000
0.000
1.000
OPA moderate intensity (per week)
Never
0.247
0.550
≤4
0.446
0.116
0.533
0.282
5∼7 days
2.797
0.570
1.577
0.847
Physical activity days with moving location (per week)
Never
0.131
0.173
≤4
1.173
0.134
1.000
0.999
5∼7 days
1.301
0.091
1.410
0.069
LPA vigorous intensity (per week)
Never
≤4
0.262
0.212
0.158
0.149
5∼7 days
LPA moderate intensity (per week)
Never
0.493
0.441
≤4
0.782
0.254
1.318
0.281
5∼7 days
1.247
0.757
1.821
0.477
Sitting hours (per day)
≤6 hours
<0.001∗∗
0.005∗
7∼12 hours
1.211
0.041∗
1.161
0.190
≥13 hours
2.275
<0.001∗∗
1.849
0.001∗
Walking (days per week)
Never
0.096
0.203
≤4
0.802
0.048∗
1.187
0.213
5∼7 days
0.953
0.704
1.310
0.078
Sleeping hours in weekdays (per week)
≥7 hours
2.007
<0.001∗∗
1.329
0.065
Sleeping hours in weekends (per week)
≥7 hours
0.591
<0.001∗∗
0.942
0.698
Alcohol consumption (within 1 year)
No experience
<0.001∗∗
0.776
No drink within recent 1 year
0.680
0.002∗
0.895
0.474
≤4 times (months)
0.491
<0.001∗∗
0.912
0.497
≥5 times (months)
0.475
<0.001∗∗
0.807
0.337
Smoking status
Never
0.262
0.246
Former smoker
0.846
0.465
0.776
0.372
Current smoker
0.690
0.134
0.637
0.144
aAdjusted by covariates (controlling age, income level, education levels, smoking status, and alcohol consumption) in multiple logistic regression analysis. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OR: odds ratio; OPA: occupational physical activity; LPA: leisure-time physical activity. ∗p<0.05; ∗∗p<0.01.


### 3.5. Association between Physical Activity and Hypertension in the Aerobic Activity Adherence Group

In the aerobic activity adherence group who answered “yes” to the question about aerobic activity adherence, there was no significant association between MSE adherence and hypertension in both unadjusted model and adjusted model with adjustment forage, quartiles of equivalent income, education levels, smoking status, and alcohol consumption.Frequency of leisure-time physical activity (LPA) level of vigorous and moderate intensity was associated with hypertension in the unadjusted model. The OR for hypertension was 0.537 (p=0.030) in ≤4 per week group and 0.314 (p=0.017) in 5∼7 per week group of vigorous intensity, respectively. They were 0.701 (p=0.032) in ≤4 per week group of moderate intensity, but it was not significant in 5∼7 per week group. The association was not significant in adjusted models.Frequency of occupational physical activity (OPA) level of moderate intensity showed increased association with hypertension in the adjusted model (in ≤4 per week group, OR = 1.931;p=0.048).Days of walking per week were significantly associated with hypertension. The OR for hypertension was 0.410 (95% CI: 0.243–0.692,p=0.001) in ≤4 per week group and 0.436 (95% CI: 0.265–0.718) in 5∼7 days per week group compared with the never walking group in the unadjusted model, respectively.They were 0.532 (95% CI: 0.284–0.997) and 0.530 (95% CI: 0.292–0.963) compared with the never walking group in the adjusted model with adjustment of age, quartiles of equivalent income, education levels, smoking status, and alcohol consumption, respectively.However, sitting hours per day and sleeping hours during week showed no significant association with hypertension in each model (Table5).Table 5
Association between physical activity and hypertension in the aerobic activity adherence group.
Items
Unadjusted OR
p value
Adjusteda OR
p value
Muscle strengthening exercises adherenceb (per week)
Never
0.879
0.527
≤4
0.928
0.693
1.292
0.259
5∼7 days
1.069
0.789
1.067
0.819
OPA vigorous intensity (per week)
Never
0.541
0.698
≤4
0.890
0.891
0.558
0.572
5∼7 days
0.300
0.270
0.422
0.516
OPA moderate intensity (per week)
Never
0.050∗
0.123
≤4
1.515
0.123
1.931
0.048∗
5∼7 days
0.509
0.074
0.859
0.725
Physical activity days with moving location (per week)
Never
0.623
0.861
≤4
1.203
0.467
1.073
0.813
5∼7 days
1.269
0.331
1.153
0.619
LPA vigorous intensity (per week)
Never
0.007∗
0.474
≤4
0.537
0.030∗
0.852
0.627
5∼7 days
0.314
0.017∗
0.538
0.251
LPA moderate intensity (per week)
Never
0.101
0.338
≤4
0.701
0.032∗
0.798
0.256
5∼7 days
0.906
0.652
1.163
0.552
Sitting hours (per day)
≤6 hours
0.323
0.845
7∼12 hours
1.211
0.133
1.002
0.991
≥13 hours
1.102
0.692
0.841
0.576
Walking (days per week)
Never
0.002∗
0.103
≤4
0.410
0.001∗
0.532
0.049∗
5∼7 days
0.436
0.001∗
0.530
0.037∗
Sleeping hours in weekdays (per week)
≥7 hours
1.335
0.076
1.182
0.409
Sleeping hours in weekends (per week)
≥7 hours
0.656
0.007∗
0.844
0.380
Alcohol consumption (within 1 year)
No experience
<0.001∗∗
0.859
No drink within recent 1 year
0.756
0.135
1.134
0.580
≤4 times (months)
0.545
<0.001∗∗
1.049
0.806
≥5 times (months)
0.403
0.001∗
0.863
0.662
Smoking status
Never
0.394
0.264
Former smoker
1.538
0.172
1.878
0.109
Current smoker
1.020
0.961
0.890
0.798
aAdjusted by covariates (controlling age, income level, education levels, smoking status, and alcohol consumption) in multiple logistic regression analysis. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OR: odds ratio; OPA: occupational physical activity; LPA: leisure-time physical activity. ∗p<0.05; ∗∗p<0.01.


## 3.1. General Characteristics of Study Population

The mean age of the 4,241 women participants from KNHANES 2016-2017 data was 58.4 (±11.4, range: 40–80 years old). Among them, 29.1% (1,234) of participants had hypertension and 92.7% were never smokers. There were 1,681 (39.6%) women in the aerobic activity adherence group and 2,560 (60.4%) participants were in the nonadherence group. For muscle strengthening exercises adherence, 3,560 (83.9%) participants never did the exercise, 465 (11.0%) did 1–4 day per week, and 215 (5.1%) did more than 5 days per week. Most participants reported no vigorous intensity physical activity for both occupation (99.5%) and leisure time (94.6%). There was a similar trend for moderate intensity physical activity (Table1).Table 1
Characteristics of the women participated in this study.
Items
n
%
Age (years)
40–49 y
1148
27.1
50–59 y
1210
28.5
60–69 y
1042
24.6
≥70 y
841
19.8
Income level
Level 1
940
22.2
Level 2
1061
25.0
Level 3
1091
25.7
Level 4
1142
26.9
Education level
Elementary
1355
32.0
Middle
568
13.4
High
1276
30.1
University
1036
24.4
Hypertension
No
3007
70.9
Yes
1234
29.1
Aerobic activity adherencea (per week)
No
2560
60.4
Yes
1681
39.6
Muscle strengthening exercises adherenceb (per week)
Never
3560
83.9
≤4
465
11.0
5∼7 days
215
5.1
OPA vigorous intensity (per week)
Never
4219
99.5
≤4
12
0.3
5∼7 days
10
0.2
OPA moderate intensity (per week)
Never
4061
95.8
≤4
108
2.5
5∼7 days
72
1.7
Physical activity days with moving location (per week)
Never
1801
42.5
≤4
1101
26.0
5∼7 days
1339
31.6
LPA vigorous intensity (per week)
Never
4011
94.6
≤4
162
3.8
5∼7 days
68
1.6
LPA moderate intensity (per week)
Never
3436
81.0
≤4
577
13.6
5∼7 days
228
5.4
Sitting hours (per day)
≤6 hours
1831
43.2
≤12 hours
2028
47.8
≥13 hours
382
9.0
Walking (days per week)
Never
823
19.4
≤4 days
1578
37.2
≥5 days
1838
43.3
Sleeping hours in weekdays (per week)
<7 hours
2594
61.2
≥7 hours
1647
38.8
Sleeping hours in weekends (per week)
<7 hours
1989
46.9
≥7 hours
2252
53.1
Alcohol consumption (within 1 year)
No experience
884
20.8
No drink within recent 1 year
834
19.7
≤4 times (months)
2147
50.6
≥5 times (months)
376
8.9
Smoking status
Never
3933
92.7
Former smoker
162
3.8
Current smoker
145
3.4
aAerobic activity adherence: 2.5-hour moderate intensity physical activity per week or 1.25-hour vigorous intensity physical activity per week. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OPA: occupational physical activity; LPA: leisure-time physical activity.


## 3.2. General Characteristics and Physical Activity Status due to Aerobic Activity Adherence

Aerobic activity adherence showed a significant association with age groups (40–49, 50–59, 60–69, and more than 70 years) (Table2). Quartiles of equivalent income and education were associated with aerobic activity adherence (p<0.05), and hypertension also showed a significant association with aerobic activity adherence. OPA and LPA days per week were significantly associated with aerobic activity adherence (p<0.05). There was a significant association between aerobic activity adherence and physical activity days with moving location. Sitting hours were significantly associated with aerobic activity adherence (p<0.05). Sleeping hours per week were associated with aerobic activity adherence (p<0.05). However, no association was found between sleeping hours during weekend and aerobic activity adherence. Alcohol consumption showed significant association aerobic activity adherence (p<0.05), but smoking status showed no association.Table 2
General characteristics and physical activity status due to aerobic activity adherence.
Items
Total
Nonaerobic (n = 2,560)
Aerobic (n = 1,681)
p value
n
n
%
n
%
Age (years)
40–49 y
1148
624
24.4
524
31.2
<0.001∗∗
50–59 y
1210
660
25.8
550
32.7
60–69 y
1042
640
25.0
402
23.9
≥70 y
841
636
24.8
205
12.2
Income level
Level 1
940
611
23.9
329
19.6
<0.001∗∗
Level 2
1061
660
25.8
401
23.9
Level 3
1091
640
25.1
451
26.8
Level 4
1142
643
25.2
499
29.7
Education level
Elementary
1355
970
38.0
385
22.9
<0.001∗∗
Middle
568
351
13.7
217
12.9
High
1276
703
27.5
573
34.1
University
1036
531
20.8
505
30.1
Hypertension
No
3007
1689
66.0
1318
78.4
<0.001∗∗
Yes
1234
871
34.0
363
21.6
Aerobic activity adherencea (per week)
No
3560
2265
88.5
1295
77.0
<0.001∗∗
Yes
465
199
7.8
266
15.8
Never
215
95
3.7
120
7.1
OPA vigorous intensity (per week)
≤4 days
4219
2557
99.9
1662
98.9
<0.001∗∗
5∼7 days
12
2
0.1
10
0.6
Never
10
1
0.0
9
0.5
OPA moderate intensity (per week)
≤4 days
4061
2533
98.9
1528
90.9
<0.001∗∗
5∼7 days
108
25
1.0
83
4.9
Never
72
2
0.1
70
4.2
Physical activity days with moving location (per week)
≤4 days
1801
1592
62.2
209
12.4
<0.001∗∗
5∼7 days
1101
710
27.7
391
23.3
Never
1339
258
10.1
1081
64.3
LPA vigorous intensity (per week)
≤4 days
4011
2550
99.6
1461
86.9
<0.001∗∗
5∼7 days
162
10
0.4
152
9.0
Never
68
0
0.0
68
4.0
LPA moderate intensity (per week)
≤4 days
3436
2412
94.2
1024
60.9
<0.001∗∗
5∼7 days
577
138
5.4
439
26.1
Never
228
10
0.4
218
13.0
Sitting hours (per day)
≤6 hours
1831
1003
39.2
828
49.3
<0.001∗∗
≤12 hours
2028
1290
50.4
738
43.9
≥13 hours
382
267
10.4
115
6.8
Walking (days per week)
Never
823
731
28.6
92
5.5
<0.001∗∗
≤4 days
1578
1126
44.0
452
26.9
5∼7 days
1838
702
27.4
1136
67.6
Sleeping hours in weekdays (per week)
<7 hours
2594
1505
58.8
1089
64.8
<0.001∗∗
≥7 hours
1647
1055
41.2
592
35.2
Sleeping hours in weekends (per week)
<7 hours
1989
1189
46.4
800
47.6
0.465
≥7 hours
2252
1371
53.6
881
52.4
Alcohol consumption (within 1 year)
No experience
884
584
22.8
300
17.8
<0.001∗∗
No drink within recent 1 year
834
535
20.9
299
17.8
≤4 times (months)
2147
1210
47.3
937
55.7
≥5 times (months)
376
231
9.0
145
8.6
Smoking status
Never
3933
2357
92.1
1576
93.8
0.091
Former smoker
162
103
4.0
59
3.5
Current smoker
145
99
3.9
46
2.7
aAerobic activity adherence: 2.5-hour moderate intensity physical activity per week or 1.25-hour vigorous intensity physical activity per week. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OPA: occupational physical activity; LPA: leisure-time physical activity. ∗p<0.05; ∗∗p<0.01.


## 3.3. Comparison of Clinical Characteristics according to the Aerobic Activity Adherence

Systolic blood pressure (SBP) and diastolic blood pressure (DBP) showed significant differences between the aerobic activity nonadherence group and aerobic activity adherence group (p<0.05). Body mass index (BMI) and HDL cholesterol showed significant differences between the two groups (p<0.05). In triglyceride, glutamate oxaloacetate transaminase (GOT), and glutamate-pyruvate transaminase (GPT) levels, there were significant differences between the two groups (p<0.05). However, total cholesterol showed no difference (Table 3).Table 3
Comparison of clinical characteristics according to the aerobic activity adherence.
Aerobic activity nonadherence group (n = 2,560)
Aerobic activity adherence group (n = 1,681)
p value
Mean
SD
Mean
SD
Mean SBP
122.05
17.73
119.25
17.42
<0.001∗∗
Mean DBP
74.58
9.51
75.17
9.32
0.048∗
BMI
24.12
3.57
23.79
3.34
0.002∗
Total cholesterol
198.51
39.27
199.82
38.15
0.294
HDL cholesterol
52.48
12.53
54.61
12.66
<0.001∗∗
Triglyceride
132.38
100.99
117.13
77.88
<0.001∗∗
AST (GOT)
22.43
9.65
21.73
8.54
0.016∗
ALT (GPT)
19.85
12.98
18.84
12.08
0.011∗
SD: standard deviation; SBP: systolic blood pressure; DBP: diastolic blood pressure; BMI: body mass index; GOT: glutamate oxaloacetate transaminase; GPT: glutamate-pyruvate transaminase.∗p<0.05; ∗∗p<0.01.


## 3.4. Association between Physical Activity and Hypertension in the Aerobic Activity Nonadherence Group

In the aerobic activity nonadherence group, the odds ratio (OR) for hypertension in muscle strengthening exercises (MSE) adherence group (1∼4 days per week) was 0.468 (95% CI: 0.322–0.681,p<0.001) in the unadjusted model and 0.554 (95% CI: 0.353–0.870) in the adjusted model with adjustment for age, quartiles of equivalent income, education levels, smoking status, and alcohol consumption, compared with the “never” group.For sitting hours, ORs for hypertension were 1.211 (95% CI: 1.008–1.455) in 7∼12 hours group and 2.275 (95% CI: 1.704–3.036) in 13 hours or longer group, compared with 6 hours or less sitting hours group in unadjusted model, respectively. They were 1.161 (95% CI: 0.929–1.451) and 1.849 (95% CI: 1.279–2.673) compared with 6 hours or less sitting hours group in the adjusted model with adjustment of age, quartiles of equivalent income, education levels, smoking status, and alcohol consumption, respectively.A significant association was found between hypertension and days of walking per week. The OR for hypertension was 0.802 (95% CI: 0.644–0.998) in ≤4 days per week group, compared with the never walking group in the unadjusted model. However, no significant association was found with hypertension after adjustment.Sleeping hours during week or weekend showed significant association with hypertension in the unadjusted model. However, the association disappeared in results from the adjusted model (Table4).Table 4
Association between physical activity and hypertension in the aerobic activity nonadherence group.
Items
Unadjusted OR
p value
Adjusteda OR
p value
Muscle strengthening exercises adherenceb (per week)
Never
<0.001∗∗
0.034∗
≤4
0.468
<0.001∗∗
0.554
0.010∗
5∼7 days
0.830
0.433
0.850
0.570
OPA vigorous intensity (per week)
Never
1.000
1.000
≤4
0.999
0.999
5∼7 days
0.000
1.000
0.000
1.000
OPA moderate intensity (per week)
Never
0.247
0.550
≤4
0.446
0.116
0.533
0.282
5∼7 days
2.797
0.570
1.577
0.847
Physical activity days with moving location (per week)
Never
0.131
0.173
≤4
1.173
0.134
1.000
0.999
5∼7 days
1.301
0.091
1.410
0.069
LPA vigorous intensity (per week)
Never
≤4
0.262
0.212
0.158
0.149
5∼7 days
LPA moderate intensity (per week)
Never
0.493
0.441
≤4
0.782
0.254
1.318
0.281
5∼7 days
1.247
0.757
1.821
0.477
Sitting hours (per day)
≤6 hours
<0.001∗∗
0.005∗
7∼12 hours
1.211
0.041∗
1.161
0.190
≥13 hours
2.275
<0.001∗∗
1.849
0.001∗
Walking (days per week)
Never
0.096
0.203
≤4
0.802
0.048∗
1.187
0.213
5∼7 days
0.953
0.704
1.310
0.078
Sleeping hours in weekdays (per week)
≥7 hours
2.007
<0.001∗∗
1.329
0.065
Sleeping hours in weekends (per week)
≥7 hours
0.591
<0.001∗∗
0.942
0.698
Alcohol consumption (within 1 year)
No experience
<0.001∗∗
0.776
No drink within recent 1 year
0.680
0.002∗
0.895
0.474
≤4 times (months)
0.491
<0.001∗∗
0.912
0.497
≥5 times (months)
0.475
<0.001∗∗
0.807
0.337
Smoking status
Never
0.262
0.246
Former smoker
0.846
0.465
0.776
0.372
Current smoker
0.690
0.134
0.637
0.144
aAdjusted by covariates (controlling age, income level, education levels, smoking status, and alcohol consumption) in multiple logistic regression analysis. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OR: odds ratio; OPA: occupational physical activity; LPA: leisure-time physical activity. ∗p<0.05; ∗∗p<0.01.


## 3.5. Association between Physical Activity and Hypertension in the Aerobic Activity Adherence Group

In the aerobic activity adherence group who answered “yes” to the question about aerobic activity adherence, there was no significant association between MSE adherence and hypertension in both unadjusted model and adjusted model with adjustment forage, quartiles of equivalent income, education levels, smoking status, and alcohol consumption.Frequency of leisure-time physical activity (LPA) level of vigorous and moderate intensity was associated with hypertension in the unadjusted model. The OR for hypertension was 0.537 (p=0.030) in ≤4 per week group and 0.314 (p=0.017) in 5∼7 per week group of vigorous intensity, respectively. They were 0.701 (p=0.032) in ≤4 per week group of moderate intensity, but it was not significant in 5∼7 per week group. The association was not significant in adjusted models.Frequency of occupational physical activity (OPA) level of moderate intensity showed increased association with hypertension in the adjusted model (in ≤4 per week group, OR = 1.931;p=0.048).Days of walking per week were significantly associated with hypertension. The OR for hypertension was 0.410 (95% CI: 0.243–0.692,p=0.001) in ≤4 per week group and 0.436 (95% CI: 0.265–0.718) in 5∼7 days per week group compared with the never walking group in the unadjusted model, respectively.They were 0.532 (95% CI: 0.284–0.997) and 0.530 (95% CI: 0.292–0.963) compared with the never walking group in the adjusted model with adjustment of age, quartiles of equivalent income, education levels, smoking status, and alcohol consumption, respectively.However, sitting hours per day and sleeping hours during week showed no significant association with hypertension in each model (Table5).Table 5
Association between physical activity and hypertension in the aerobic activity adherence group.
Items
Unadjusted OR
p value
Adjusteda OR
p value
Muscle strengthening exercises adherenceb (per week)
Never
0.879
0.527
≤4
0.928
0.693
1.292
0.259
5∼7 days
1.069
0.789
1.067
0.819
OPA vigorous intensity (per week)
Never
0.541
0.698
≤4
0.890
0.891
0.558
0.572
5∼7 days
0.300
0.270
0.422
0.516
OPA moderate intensity (per week)
Never
0.050∗
0.123
≤4
1.515
0.123
1.931
0.048∗
5∼7 days
0.509
0.074
0.859
0.725
Physical activity days with moving location (per week)
Never
0.623
0.861
≤4
1.203
0.467
1.073
0.813
5∼7 days
1.269
0.331
1.153
0.619
LPA vigorous intensity (per week)
Never
0.007∗
0.474
≤4
0.537
0.030∗
0.852
0.627
5∼7 days
0.314
0.017∗
0.538
0.251
LPA moderate intensity (per week)
Never
0.101
0.338
≤4
0.701
0.032∗
0.798
0.256
5∼7 days
0.906
0.652
1.163
0.552
Sitting hours (per day)
≤6 hours
0.323
0.845
7∼12 hours
1.211
0.133
1.002
0.991
≥13 hours
1.102
0.692
0.841
0.576
Walking (days per week)
Never
0.002∗
0.103
≤4
0.410
0.001∗
0.532
0.049∗
5∼7 days
0.436
0.001∗
0.530
0.037∗
Sleeping hours in weekdays (per week)
≥7 hours
1.335
0.076
1.182
0.409
Sleeping hours in weekends (per week)
≥7 hours
0.656
0.007∗
0.844
0.380
Alcohol consumption (within 1 year)
No experience
<0.001∗∗
0.859
No drink within recent 1 year
0.756
0.135
1.134
0.580
≤4 times (months)
0.545
<0.001∗∗
1.049
0.806
≥5 times (months)
0.403
0.001∗
0.863
0.662
Smoking status
Never
0.394
0.264
Former smoker
1.538
0.172
1.878
0.109
Current smoker
1.020
0.961
0.890
0.798
aAdjusted by covariates (controlling age, income level, education levels, smoking status, and alcohol consumption) in multiple logistic regression analysis. bMuscle strengthening exercises adherence: push-up, sit-up, dumbbell, or other types of muscle exercises more than 2 days during 1 week recently. OR: odds ratio; OPA: occupational physical activity; LPA: leisure-time physical activity. ∗p<0.05; ∗∗p<0.01.


## 4. Discussion

In the aerobic activity nonadherence group, women who had sedentary lifestyle such as long sitting hours showed increased association with hypertension and women who showed endurance and muscle strengthening exercise adherence were associated with decreased odds ratios of hypertension. Particularly, they showed increased association with hypertension along with increment of sitting hours, which is closely related to the level of occupational physical activity.Previous studies on the effects of occupational physical activity (OPA) on hypertension are inconsistent [19]. OPA has also been shown to lower the risk of hypertension [15]; on the contrary, in the report of increasing risk in black men, it is considered that research on various population groups is necessary in consideration of racial differences, which supports the necessity of this study [20]. In addition, all-cause mortality has been reported as well as hypertension [21]. Potential hypothesis raised to date includes the risk of anaerobic components or injuries [14], adverse social determinants and demanding job characteristics [17], and motion characteristics of OPA which is not helpful for cardiopulmonary function [21].On the other hand, the mechanism of cardiovascular diseases due to increased sitting hours due to occupation has been explained more clearly. Decreased local contraction of muscles interferes with lipoprotein lipase activity, leading to an increase in triglycerides and a decrease in high-density lipoprotein cholesterol [22]. It is not easy to measure heterogeneous types of OPAs and working environment for the mechanisms by which OPAs pose a risk of hypertension [17], but further research is needed for clarification.In the aerobic activity adherence group, women doing occupational physical activity of moderate intensity showed increased association with hypertension. Frequency of walking, e.g., days of walking per week, was associated with decreased odds ratios of hypertension in this group.The relationship between physical activity and hypertension has been reported many times. The previous studies also reported impacts on RCT interventions and risk of coronary heart disease. In the study of Twinamasiko, the mean systolic blood pressure was higher in the sedentary work style group [16]. In a recent meta-analysis of 26 RCTs on physical activities, it was reported that physical activities, even with higher intensity, were associated with reduction in blood pressure in the participants with hypertension [23–26]. Meeting the target of American Physical Activity Guideline resulted in a 14% reduced risk of coronary heart disease compared with inactive people in adults [8]. Also, there was a research identifying the fact that daily physical activity was associated with blood pressure particularly in women [27].Several studies reported that the mechanisms leading to reducing blood pressure by physical activity were related to cardiac remodelling, endothelial function, decreased oxidative stress, and the inflammation syndrome [28–30]. The mechanism by which aerobic exercise training lowers blood pressure in hypertensive patients has been reported for some time, and the mechanism has been suggested to be related to the sympathetic nerve activity (SNA) [31]. However, evidence suggests that muscle SNA is associated with the central sympathetic nerve activity (SNA) [32]. After 4 months of moderate intensity aerobic exercise training in hypertensive patients with unsuccessful treatment, initial excessive central sympathetic activation decreased, accompanied by decreased muscle SNA and improved arterial baroreflex regulation of SNA [33]. Usual pharmacological approaches for essential hypertension have not focused on regulating central sympathetic outflow, and the emerging therapeutic strategies targeting neurogenic hypertension such as aerobic exercise training, weight loss, stress reduction, central sympatholytics such as moxonidine or rilmenidine, statins, and surgical interventions such as therapeutic renal sympathetic denervation have implications for clinical management of hypertension [32]. Walking was identified to be related to decreased risk of hypertension in participants who showed adherence to aerobic activity, while increased sitting hours could lead to increased risk of hypertension in the participants not adhered to the regular aerobic activity. In Hu’s report (2007), hypertensive women had the benefit of reduced cardiovascular mortality from all the type of physical activities such as occupational, leisure-time and daily “walking or cycling to and from work.” Because of these results, walking in women can be consistently recommended [15]. There have been a number of researches reporting that regular or chronic dynamic aerobic and resistance training would be effective on reductions in blood pressure of the patients with hypertension [34–36]. In addition to moderate-vigorous physical activity, the BP lowering effect of reducing sedentary hours through interrupting prolonged sitting was recently reported and “sit less” has been recommended [37]. When this “breaks in prolonged sitting” was performed with morning exercise, it was effective to control BP in obese older adults, particularly in women [38].Also it was demonstrated that the largest isometric training resulted in reductions of blood pressure in hypertensive patients which was similar to aerobic exercise training [34, 39, 40]. Moreover, the combination of muscle exercises and aerobic activity could be effective in controlling blood pressure [41]. In this study, even the participants without aerobic activities nonadherence demonstrated that regular muscle exercise was associated with decreased risk of hypertension.There are several limitations in interpreting the results of this study. First, it was not possible to demonstrate any causal relationship between physical activities and hypertension in women aged from 40 to 80 years because of the cross-sectional design of this study. Secondly, there was no significant association between leisure-time activities and hypertension in neither adherence nor nonadherence group. This may be due to the small number of active women in the nonadherence group. Finally, there was no consideration that it was surgical menopause or natural menopause. Information on the risky components in the work activities such as chemical, mechanical injury, or job stress was insufficient to analyze the association between occupational physical activity and hypertension. A more comprehensive study may be necessary to overcome those limitations.


## 5. Conclusion

In the aerobic activity adherence group, women doing occupational physical activity of moderate intensity showed increased association with hypertension. Further research that identifies the dangerous components in occupational physical activity is warranted. Walking seems to have benefits and be appropriate to be recommended. In the aerobic activity nonadherence group, women who had long sitting hours showed increased association with hypertension, and women who showed endurance exercise adherence were associated with decreased odds ratios of hypertension. Decreasing sitting hours and increasing endurance exercise may be helpful for this group.



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*Source: 8943492-2020-02-14.xml*