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Comparison of electrocardiogram findings and lifestyles between urbanized people and ger-living people in Ulaanbaatar, Mongolia
Atherosclerosis 175 (2004) 101–108
Comparison of electrocardiogram findings and lifestyles between urbanized people and ger-living people in Ulaanbaatar, Mongolia Fumio Komatsu a,∗ , Kyoko Hasegawa a , Sanae Watanabe a , Terue Kawabata a , Yoshiko Yanagisawa a , Yoshinori Kaneko a , Shigeji Miyagi a , Mitsuru Sakuma a , Yasuo Kagawa a , Chimedregzen Ulziiburen b , Luvsanbasaryu Narantuya b a
High-Technology Research Group C, Kagawa Nutrition University, 3-9-21 Chiyoda, Sakodo, Saitama 350-0288, Japan b Public Health Institute, Ulaanbaatar, Mongolia Received 20 August 2003; accepted 5 March 2004 Available online 8 May 2004
Abstract In Ulaanbaatar, lifestyles differ between urbanized people (group A) and ger (tent)-living people (group B). Group A earn high annual incomes and live in houses or apartments. Group B (who had moved to Ulaanbaatar from nomadic areas) earn low incomes and live in narrow gers. In 2002, we investigated daily food intake, health status, and electrocardiogram (ECG) in these groups. In total, 256 subjects (group A, 142; group B, 114) were enrolled. Group A ate meat, vegetables, and fruits high enough by a Western style. Group B consumed meat but ate only small amounts of vegetables and fruits. They took a lot of fat, however, the serum lipid levels of them were not so high. The fat source as energy was plant oil for cooking rather than meat. Several abnormal ECG findings including left ventricular hypertrophy (LVH) were found in 32 (22.5%) of group A and 50 (43.9%) of group B (P < 0.001). LVH was also found more in group B than in group A. LVH in group A males was accompanied by high body weight (BW), hypertension, and high LDL-cholesterol, whereas LVH in group B males seemed to be related to an unbalanced diet, high salt intake, smoking, and some low socio-economic problems. In order to promote health condition, such risk factors should securely be eliminated from the lifestyles. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Mongolia; ECG; Lifestyle; Urbanized people; Ger-living people
1. Introduction Human health and life span are generally affected by lifestyles. Mongolia has a population of 2 410 000, with mean average life span in 2002 being 64.4 years for males and 67.3 years for females, and infant mortality being 34.1/1000 [1]. In Japan, mean average life span in 2002 was 77.9 years for males and 84.7 years for females, and infant mortality was 4.2/1000 [2]. Recently, Swinburn [3] surveyed Mongolian health conditions, and found that the prevalence of non-communicable diseases such as hypertension, stroke, ischemic heart disease, and diabetes mellitus are increasing in Mongolians. In Ulaanbaatar, the ∗ Corresponding author. Tel.: +81-49-282-3702; fax: +81-49-284-6410. E-mail address: [email protected] (F. Komatsu).
capital of Mongolia, living environments and lifestyles differ between urbanized people (group A) and ger (tent)-living people (group B). The people of group A earn high annual incomes and live in houses or apartments in the central area of Ulaanbaatar. Meanwhile, the people of group B (who had moved to Ulaanbaatar from nomadic areas) earn low incomes and live in traditional tents on the outskirts of Ulaanbaatar. In 2002, we investigated daily food intake, health status, and electrocardiogram (ECG) in these groups and found several differences between them. In particular, we noticed that abnormal ECG findings including left ventricular hypertrophy (LVH) were more prevalent in group B than in group A. In this report, we describe the ECG findings and the results of daily food investigations, anthropometric measurements, and serum lipid analyses, which may be related to these ECG abnormalities.
0021-9150/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2004.03.005
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2. Methods
2.4. ECG examination
2.1. Subjects
ECG examination was performed by medical doctors and well-trained laboratory technicians. The Cardiofax 9120 ECG apparatus (Nippon Koden Co., Tokyo, Japan) was used. LVH was diagnosed if the subjects had RV5 + SV1 4.0 mV and other following findings; left atrium overload, right and left bundle branch blocks, left axial deviation, ST depression, and decreased T wave. Tall R wave alone in thin subjects was not considered to indicate LVH. Statistical significance was calculated by the χ2 -test and Student’s t-test, and P < 0.05 was considered to indicate significant difference.
A total of 256 subjects (group A, 142; group B, 114), ranging in age from 25 to 75 years, were enrolled. These subjects were healthy at the time of examination, although some had been medicated. In order to observe living environments, we visited some representative houses, apartments, and gers. Informed consent was obtained from all subjects. 2.2. Investigation of daily food intake Daily food intake was investigated using the Food Frequency Questionnaire method. All subjects were interviewed by well-trained native food specialists using the time from 30 to 45 min for each subject. In order to confirm the quantities, pictures, and photos of pan; pot, ladle, and dish were shown to the subjects. The specialists calculated a total of daily food intake using the Standard Tables of Food Composition in Mongolia [4]. 2.3. Anthropometric measurements and serum lipid analyses Blood pressure (BP), body weight (BW), body mass index (BMI), and percent body fat (%BF) were measured. BMI (kg/m2 ) were calculated from the measurements of minimal waist circumference and maximal hip circumference. %BF was indicated using a bioelectrical impedance meter (TBF-110, Tanita Co., Tokyo, Japan). Handgrip power was also measured using a handgrip meter (Type 6103, Tanita Co.). Blood samples were obtained, frozen for storage, and transported to Tokyo. Serum lipid levels were assayed at a commercial laboratory (SRL Inc., Tokyo, Japan). Total cholesterol was assayed by a cholesterol oxidation method, HDL-cholesterol by a selective inhibition test, and LDL-cholesterol and triglyceride by enzyme methods.
3. Results 3.1. Ages, monthly incomes and environments of group A and group B (1) The subjects were members of husband/wife couples. Mean average age was 49.8 ± 14.2 years for group A males (n = 71, mean ± S.D.), 49.7 ± 14.3 years for group B males (n = 57), 47.2 ± 13.1 years for group A females (n = 71), and 47.2 ± 13.2 years for group B females (n = 57). There were no inter-group differences in age for males or females. As shown in Fig. 1, the subjects were divided into 10-year age groups. There was roughly equal distribution among these 10-year age generations. (2) Mean average monthly income for one couple was as follows: group A, 158 605.6 ± 152 770.9 Tugrug (n = 71, mean ± S.D.); group B, 67 828.3 ± 30 784.5 Tugrug (n = 57). Group A people earned significantly higher monthly incomes than group B people (P < 0.01). Group B people generally worked hard as physical laborers. (3) Group A people lived in comfortable houses or modern apartments in the central area of Ulaanbaatar, and their
Fig. 1. The number of subjects in 10-year age groups.
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Table 1 The daily intake of foods in groups A and B Group A (n = 142) Mean ± S.D. (g) Rice White bread Black bread Black flour Noodle Potato Meat and meat products Egg Fish Vegetable Fruit Milk and dairy products Fat Sugar Salt for cooking Green tea Black tea Vodka Total
67.2 102.7 12.2 5.7 20.2 94.9 193.9 15.5 9.4 226.2 152.5 280.0 37.7 11.6 3.2 329.7 133.4 8.5
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
50.4 63.0 23.7 24.7 27.3 57.0 100.3 21.0 18.2 184.3 179.8 237.1 56.5 15.7 1.9 241.7a 161.4 17.4
Group B (n = 114) Mean ± S.D. (kcal) 232 243 25 19 71 84 353 24 10 72 72 174 339 46 0 16 1 17 1801
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
Mean ± S.D. (g)
174 149 49 84 96 50 183 33 20 59 85 147 508 63 0 12 2 35 1747
50.5 85.9 2.5 14.8 8.9 70.1 168.5 4.4 4.6 108.1 59.4 244.0 62.7 9.6 5.9 459.0 37.7 9.7
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
33.1 61.0 6.7 35.1 10.9 50.0 79.1 7.8 11.4 83.3 86.1 208.7 77.3 10.9 9.9 337.3a 85.7 20.2
Mean ± S.D. (kcal) 174 204 5 50 31 62 307 7 5 35 28 151 564 38 0 23 0 19 1703
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
∗∗
114 145 14 120 38 44 144 12 13 27 40 129 695 43 0 17 1 40 1636
∗ ∗∗∗ ∗ ∗∗∗ ∗∗ ∗ ∗∗∗ ∗ ∗∗∗ ∗∗∗ ∗∗ ∗∗ ∗∗∗ ∗∗∗
All values are given as mean ± S.D. Money spent for foods: group A, # ± 12793.3 and group B, # ± 9114.4 (P < 0.01). a Values are expressed in ml. ∗ P < 0.05. ∗∗ P < 0.01. ∗∗∗ P < 0.001.
families comprised three to five members. They drank public service water and used flush toilets. Meanwhile, group B people lived in narrow gers on the outskirts of Ulaanbaatar, with 8–12 people per family. They drank water from a well (one well was located in the center of each ger settlement), and used a drop hole toilet with night-soil collection. 3.2. Daily intake of foods, salt and alcohol, and smoking The results of investigation of daily intake of foods in group A and group B are shown in Table 1. Group A people generally took significantly higher amounts of the foods than group B people. Group A people consumed higher total
calories than group B people, although the difference was not significant (group A people, 1801 ± 1747 kcal; group B people, 1703 ± 1636 kcal). Money spent for foods was 15 162.9 ± 12 793.3 Tugrug per month in group A and 10 118.6 ± 9114.4 Tugrug per month in group B, the difference being significant (P < 0.01). Group A people routinely took a Western style diet and ate sufficient amounts of meat, vegetables, and fruits. Meanwhile, group B people took a traditional-style diet. They consumed meat but ate only small amounts of vegetables and fruits because the vegetables and fruits are imported from China and are expensive for them. Group B people took a higher amount of fat than group A people as shown in Table 1 (P < 0.01). In Table 2, the percentages of protein, fat, and carbohydrate, and the sources of the fat were shown. The percentage of fat in daily calories
Table 2 The energy percentage of protein, fat, and carbohydrate and fat sources in groups A and B Group A (n = 142)
Protein Fat Carbohydrate Fat source Meat Fish Plant oil
Group B (n = 114)
Mean ± S.D. (g)
Mean ± S.D. (kcal)
Percentage
Mean ± S.D. (g)
Mean ± S.D. (kcal)
Percentage
78 ± 62 63 ± 54 230 ± 177
312 ± 248 567 ± 486 920 ± 708
17.3 31.5 51.2
65 ± 43 84 ± 65 172 ± 108
260 ± 172 756 ± 585 688 ± 432
15.3 44.4 40.3
35 ± 31 1.8 ± 2.2 25 ± 33
353 ± 183 10 ± 20 339 ± 508
50 1 49
22 ± 35 0.2 ± 0.7 61 ± 78
307 ± 144 5 ± 13 564 ± 695
35 1 64
All values are given as mean ± S.D. ∗∗ P < 0.01.
∗∗ ∗∗ ∗∗ ∗∗ ∗∗
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was higher in group B than in group A. Group B people took the fat energy from plant oil for cooking rather than from meat. Furthermore, group B people used salt exceedingly. Daily salt usage for cooking in group B was larger volume than that in group A as shown in Table 1 (P < 0.01). Group B males routinely drank vodka, which has a very high alcohol percentage, whereas group A people preferred whisky to vodka. But there was no difference in the volume of alcohol consumed between these groups. Most group B males were smokers, and one-fourth of group A males were smokers. 3.3. Anthropometric measurements The height of the subjects was as follows: group A males, 168.3 ± 4.8 cm; group B males, 166.3 ± 4.5 cm; group A females, 155.8 ± 4.7 cm; and group B females, 153.7 ± 4.4 cm. Both males and females in group A (P < 0.05) were significantly taller in the height than those in group B (P < 0.05). Mean averages of systolic blood pressure, body weight, body mass index, and percent body fat are shown in Fig. 2. There was no significant difference in systolic BP between
these groups. But group A males demonstrated significantly higher BW, BMI, and %BF than group B males. Handgrip power was 41.7 ± 9.3 kg for group A males, 37.1 ± 6.4 kg for group B males, 27.1 ± 5.9 kg for group A females, and 24.0 ± 5.9 kg for group B females. There were significant differences between both males (P < 0.05) and females (P < 0.05). The handgrip power was also compared among high-age subjects (age 45 years). It was 38.8 ± 9.9 kg for group A males, 34.3 ± 5.5 kg for group B males, 25.4 ± 5.4 kg for group A females, and 22.0 ± 5.3 kg for group B females. There were significant differences between both males (P < 0.05) and both females (P < 0.05). This finding suggests that aging may progress faster in group B than in group A. 3.4. Serum lipid levels The serum levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride are shown in Fig. 3. With the exception of triglyceride in females, there were no significant differences between groups A and B. There were no apparent gender differences. As shown in Tables 1 and 2, although group B people took a higher amount of daily fat than group A people, the serum lipid levels were not so high.
Fig. 2. The levels of systolic blood pressure (BP), body weight (BW), body mass index (BMI), and percent body fat (%BF) in groups A and B (group A: male, 71; female, 71 and group B: male, 57; female, 57. Mean ± S.D., ∗∗ P < 0.01).
F. Komatsu et al. / Atherosclerosis 175 (2004) 101–108
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Fig. 3. The levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride (group A: male, 71; female, 71 and group B: male, 57; female, 57. Mean ± S.D., ∗ P < 0.05).
3.5. ECG examination (1) Some of the subjects showed several abnormal ECG findings. They had two or three changes such as LVH, sinus bradycardia, overload of left atrium, PR shortness, supra-ventricular and ventricular premature contractions, atrial fibrillation, atrio-ventricular block, left and right bundle branch blocks, intraventricular conduction disturbance, ST elevation, ST depression, tall T wave, flat T wave, and negative T wave. These abnormal findings were observed in 32 (22.5%) of group A and 50 (43.9%) of group B people. Frequency of them was higher in group B than in group A (P < 0.001). (2) Relationship between the ECG abnormalities and age is shown in Table 3. Incidence of the abnormalities increased with age. They were found in 18/71 (25.4%) of group A males, 33/57 (57.9%) of group B males, 14/71 (19.7%) of group A females, and 17/57 (29.8%) of group B females. The abnormalities were found in males more than in females. There was a significant difference between group A and B males (P < 0.001). (3) In these abnormalities, the difference of incidence of LVH was conspicuous. As shown in Table 3, LVH was
observed among high-age subjects (age 45 years): group A males, 3/71 (4.2%); group B males, 11/57 (19.3%); group A females, 0/71; and group B females, 4/57 (7.0%). For males, there was a significant difference (P < 0.01). (4) Because LVH was observed among high-age subjects (in particular in males), we compared the anthropometric measurements and serum lipid levels between the LVH males and normal-ECG males (age 45 years). As shown in Tables 4 and 5, LVH in group A males was accompanied by hypertension, high BW, and high LDL-cholesterol level. However, LVH in group B males was not always accompanied by such findings. The LVH males of group B showed a wide range of BP: some had hypertension and others had normal BP. They were relatively low BW and low %BF. Furthermore, they showed low LDL-cholesterol compared to the LVH males of group A. These findings suggest that in group A males, LVH may be related to high BW, hypertension, and high LDL-cholesterol, whereas there is no such apparent relationship in group B males. LVH in group B males may be connected with unbalanced diet, high salt intake, smoking, and other factors.
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Table 3 The number of abnormal ECG findings in each generation Age
Group A, males
Group B, males
Group A, females
Group B, females
Total
Abnormal
Total
Abnormal
Total
Abnormal
Total
Abnormal
Abnormal ECG 25–34 12 35–44 18 45–54 11 55–64 17 65–75 13 Total 71 Age Total
2 2 0 7 7 18 (25.4)∗∗∗ LVH
11 12 11 14 9 57 Total
3 3 9 13 5 33 (57.9)∗∗∗ LVH
15 17 19 11 9 71 Total
1 2 6 3 2 14 (19.7) LVH
12 14 13 13 5 57 Total
0 2 8 3 4 17 (29.8) LVH
LVH 25–34 35–44 45–54 55–64 65–75 Total
0 0 0 2 1 3 (4.2)∗∗
11 12 11 14 9 57
0 0 3 6 2 11 (19.3)∗∗
15 17 19 11 9 71
0 0 0 0 0 0 (0)
12 14 13 13 5 57
0 0 1 1 2 4 (7.0)
12 18 11 17 13 71
Values in parenthesis are in percentage. ∗∗ P < 0.01. ∗∗∗ P < 0.001. Table 4 The levels of systolic blood pressure, body-weight, and body mass index (BMI) and percent body fat (%BF) of the LVH males and normal-ECG males (age 45 years) Parameter
Group
Finding
n
Mean ± S.D.
Blood pressure (mmHg)
A
Normal-ECG
53
127.7 ± 18.6]∗∗
LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH
3 24 11 53 3 24 11 53 3 24 11 53 3 24 11
169.0 123.6 157.5 66.9 73.3 61.9 58.9 25.6 25.5 22.3 22.4 29.2 28.9 22.6 22.6
B Body weight (kg)
A B
BMI
A B
%BF
A B
± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
3.6]∗∗ 21.5]∗∗ 24.9 14.1]∗ 7.1]∗∗ 13.1 7.2 3.7]∗∗ ]∗∗ 1.2 4.1 3.1 8.1]∗∗ ]∗ 2.4 9.3 6.5
were generally hard workers. Group B people drank water from a well and used drop hole toilets. In 2002, the Japan International Cooperation Agency (JICA) reported that Ulaanbaatar had been fully equipped with water works and sewerage systems [5] but the living environments that we observed in the ger settlement differed from that assessment. Group A people consumed high amounts of foods compared to group B people. Money spent for foods was greater in group A than in group B. Group A people took a Western-style diet and ate meat, vegetables, and fruits high enough. Whereas, group B people consumed meat but
Table 5 The levels of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride of the LVH males and normal-ECG males (age 45 years) Parameter
Group
Finding
n
Mean ± S.D.
Total cholesterol (mg/dl)
A
Normal-ECG
53
186.2 ± 34.2
LVH Normal-ECG LVH Normal-ECG
3 24 11 53
216.0 178.2 175.4 54.4
± ± ± ±
6.6]∗ 31.0 31.9 11.5
LVH Normal-ECG LVH Normal-ECG
3 24 11 53
55.7 54.7 56.9 116.3
± ± ± ±
4.0 11.5 14.8 30.6
LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH
3 24 11 53 3 24 11
146 107.8 104.7 109.5 106.7 113.2 99.2
± ± ± ± ± ± ±
3.6]∗ ]∗ 25.7 25.2 65.3 39.8 145.6 86.5
∗
P < 0.05. ∗∗ P < 0.01.
B HDL-cholesterol (mg/dl)
4. Discussion In this study, we investigated the lifestyles, daily food intake, health status, and ECG findings in urbanized people (group A) and ger-living people (group B) of Ulaanbaatar, and found several differences between these two groups. The main reason of differences was considered to be due to socio-economic conditions. Group A people earned high monthly incomes and lived in comfortable houses or modern apartments but group B people earned only low incomes and lived in narrow gers with many family members. They
A
B LDL-cholesterol (mg/dl)
A
B Triglyceride (mg/dl)
A B
∗
P < 0.05.
F. Komatsu et al. / Atherosclerosis 175 (2004) 101–108
ate only small amounts of vegetables and fruits. Group B people took a lot of fat. The percentage of fat in daily calories of this group was very high. They took the fat energy from plant oil for cooking rather than from meat. This food style was different from that of group A people. Group A people used 3.2 g of salt for cooking and group B people used 5.9 g. In Japanese, salt usage for cooking is 1.2 g [6]. This finding indicates that the inhabitants in Ulaanbaatar, particularly group B people, use high quantities of salt for cooking. Recent nutritional research in Mongolia reported that total daily salt intake in Mongolian is 16.7 g [7], which is very high compared to Japanese, where it is 12.3 g [6]. Theses diet styles may affect to the health status. Group B males had lower BW, lower BMI, and lower %BF than group A males. Furthermore, group B people showed lower handgrip power than group A people. The difference increased with age. Aging may progress faster in group B than in group A. We also compared serum lipid levels between these groups. With the exception of triglyceride in females, we found no significant differences in the serum lipid levels between these two groups. Although group B people took a high amount of daily fat, they demonstrated not so high levels. Concerning the total cholesterol, group A males showed 186.8 mg/dl; group B males, 184.9 mg/dl; group A females, 188.6 mg/dl; and group B females, 185.7 mg/dl. In Japanese adults (age 20 years), mean average total cholesterol level is 198.0 mg/dl for males and 203.7 mg/dl for females [6]. It is conspicuous that Mongolians including both groups A and B are in low total cholesterol compared to Japanese. The reason is unknown. Previously, Shaper et al. [8] surveyed the serum lipids of the Samburu tribe people in Northern Kenya because these nomadic people took a diet consisting almost entirely of milk, meat, and animal blood of cattle and camels. They found that the people did show no increase in cholesterol level, no rise in blood pressure, or no prevalence of ischemic heart disease. Thus, they speculated that the low serum lipid might be related with a high degree of their physical activities. In Mongolians, in particular in group B people, the physical activity (hard labor) may be one of the reasons of low serum lipids. But such low levels of serum lipids do not seem to be explained by the physical activity alone. It is known that Pima Indians in Arizona, USA, also show low cholesterol levels despite high intake of saturated fat [9,10]. Both Mongolians and Pima Indians may utilize efficient hepatic clearance of cholesterol into bile [3]. It would be interesting to know whether or not Mongolians and Pima Indians have the same ancestor in spite of very far distance between these two areas. In this study, we performed ECG examination in the subjects and found several abnormal ECG findings at a high frequency. Concerning the ECG examination, there are some reports. Olziikhutag and Danilov [11] performed ECG examination in 1357 aboriginal males of Mongolia and found nonspecific changes in T wave and ST segment at a frequency of 14.6–21.9%. They considered that the nonspecific
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myocardial changes might be due to cold as well as altitude factor. Manaseki [12] also stated that ischemic heart diseases were common in Mongolia. Recently, Swinburn [3] surveyed Mongolian health conditions and found that hypertension, stroke, ischemic heart disease, and diabetes mellitus are prevalent in Mongolians and reported that the high prevalence of them may be due to the lifestyles of the people. In the present study, in particular, we compared the prevalence of abnormal ECG findings between groups A and B. It is very interesting because the precise comparison of it between the urbanized people and ger-living people had not been reported. The abnormalities including LVH were recognized with a greater frequency in group B than in group A. As the reasons, we should consider many things such as economic condition, living environments, daily diet, smoking, hard labor, and others. Of course, because group B people had lived in nomadic areas before they moved to Ulaanbaatar, their heart might have already been influenced by the cold temperature as described by Olziikhutag and Danilov [11]. The temperature decreases to −40 ◦ C in winter. The severe climate may affect to the heart function of them. In this discussion, we mention about the mechanisms of LVH. Although LVH is caused by several mechanisms, the following three mechanisms may be important: (a) high body weight → hypertension → LVH, (b) high salt intake and smoking → hypertension and arteriosclerosis → LVH, and (c) infection → endocarditis → heart valve disease → LVH. Mechanism (a): high body weight often induces hypertension. The hypertension imposes a load on the left ventricle resulting LVH. High body weight is often accompanied by hypercholesterolemia, which induces atherosclerosis, LVH, and chronic heart diseases [13]. Nasyrov et al. [14] stated that in Russia, prevalence of myocardium and coronary heart diseases was about 3.5 times higher in people who were hypertensive and overweight, and was 2–2.5 times higher in people with hypercholesterolemia. High body weight, hypercholesterolemia, and hypertension may be due to Western-style diet. For three decades, Western-style diets have also been popular among Japanese people, many of whom now exhibit such unhealthy status [6]. In group A males, LVH was accompanied by high body weight, hypertension, and high LDL-cholesterol in spite of low cholesterolemia in Mongolians. This suggests that LVH in group A males is caused by mechanism (a). Mechanism (b): hypertension and arteriosclerosis are often induced by high salt intake [15,16] and smoking. Group B people consumed a high-salt diet, and most males of group B were smokers. Prolonged smoking contributes to hypertension, LVH, stroke, and ischemic heart diseases [17,18]. In the present study, LVH was observed in males more frequently than in females; this may be related to the smoking, drinking, and hard labor. Thus, LVH in group B may be due to mechanism (b), although the mechanism (a) may also be involved in part. Mechanism (c): LVH is also connected with heart valve disease, which is often caused by bacterial infection. In
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Mongolia, several infections are prevalent [19]. Betahemolytic streptococcus infection is one of them. Drinking of well water and using of drop hole toilets may be related with this infection. This infection often causes rheumatic fever (RF) and endocarditis, and then heart valve disease and LVH after 20–30 years. RF is rare in developed countries. However, it still remains endemic in many developing countries, particularly in Asia and Africa [20,21]. Prevalence of RF is connected with low socio-economic status. The World Health Organization (WHO) [22] surveyed the prevalence of rheumatic fever and rheumatic heart disease in 16 developing countries and found a high prevalence in Asian, African, and Eastern Mediterranean regions. Rheumatic heart disease is a serious cause of morbidity and mortality in developing countries [23–25]. According to these previous reports, we speculate that some of the LVH in group B may be due to mechanism (c) such as rheumatic heart valve disease. We further speculate that rheumatic heart disease may affect the life span in this group because it is known that mortality is high in tent-living people [26]. However, in the present investigation, we did not confirm the heart valve disease using an X-ray photo or an ultrasonic generator because the high prevalence of LVH was noticed after the data were collected. Assessment of the prevalence of heart valve disease may shed further light on the present findings. In conclusion, in the present study, we found several abnormal ECG findings including LVH at a high frequency. Group A people are in a high risk condition of LVH due to high body weight, hypertension, and high LDL-cholesterol, which may be connected with a Western style diet. Whereas, group B people need to correct their unbalanced diet, high salt intake, smoking, hard labor, and others. We also propose that high frequency of LVH may be related to the incomplete treating of streptococcus infection and RF in the early stage. In order to promote health status, such risk factors should securely be eliminated from the lifestyles.
References [1] Data Book of the World 2002. Tokyo, Japan: Ninomiya-Shoten Publishing Co. Ltd.; 2003. [2] International Statistical Compendium 2002, Statistics Bureau, Ministry of Public Management. Home Affairs, Posts and Telecommunications, Japan; 2003. [3] Swinburn B. Non-communicable disease control in Mongolia. DRAFT summary report. WHO consultation, 8–16 May 2002. p. 1–12. [4] Oyunbileg M, Altantsooj S, Baljmaa B, Enkhtungalag B, editors. The National Nutrition Survey in Mongolia; 1997. [5] Country profile of environment in Mongolia by Planning and Evaluation Department. Japan International Cooperation Agency in Japan; 2002. [6] The National Nutrition Survey in Japan 2000. The Ministry of Health, Labor and Welfare, Japan; 2002.
[7] United Nations Children’s Fund (UNICEF). Nutrition status of population of Mongolia 2000. Ulaanbaatar, Second National Nutrition Survey; 2002. [8] Shaper AG, Jones KW, Jones M, Kyobe J. Serum lipids in three nomadic tribes of northern Kenya. Am J Clin Nutr 1963;13:135– 46. [9] Savage PJ, Hamman RF, Bartha G, Dippe SE, Miller M, Bennett PH. Serum cholesterol levels in American (Pima) Indian children and adolescents. Pediatrics 1976;58:274–82. [10] Fagot-Campagna A, Narayan V, Hanson RL, et al. Plasma lipoproteins and incidence of non-insulin-dependent diabetes mellitus in Pima Indians: protective effect of HDL cholesterol in woman. Atherosclerosis 1997;128:113–9. [11] Olziikhutag A, Danilov IP. Incidence of nonspecific myocardial changes in the native inhabitants of different climatic and geographical areas of Mongolia. Kardiologiia 1987;27:36–9. [12] Manaseki S. Mongolia: a health system in transition. Br Med J 1993;307:1609–11. [13] Nickerson CJ, Haudenschild CC, Chobanian AV. Effects of hypertension and hyperlipidemia on the myocardium and coronary vasculature of the WHHL rabbit. Exp Mol Pathol 1992;56:173– 85. [14] Nasyrov MM, Tursunov S, Kasymova ND, Mashrapova DZ. Ischemic heart disease and its relation to basic risk factor among the rural population. Ter Arkh 1985;57:22–4. [15] Barone FC, Campbell WG, Nelson AH, Feuerstein GZ. Carvedilol prevents severe hypertensive cardiomyopathy and remodeling. J Hypertens 1998;16:871–84. [16] Nishikawa N, Yamamoto K, Sakata Y, et al. Differential activation of matrix metalloproteinases in heart failure with and without ventricular dilatation. Cardiovasc Res 2003;57:766–74. [17] Torok J, Gvozdjak A, Kucharska J, et al. Passive smoking impairs endothelium-dependent relaxation of isolated rabbit arteries. Physiol Res 2000;49:135–41. [18] Simko F, Braunova Z, Kucharska J, Bada V, Kyselovic J, Gvozdjakova A. Passive smoking induced hypertrophy of the left ventricle: effect of captopril. Pharmazie 1999;54:314. [19] Toyota M, Yasuda N, Koda S, Ohara H, Enkhbat S, Tsogt G. Clinical characteristics differentiating bacteriologically positive pulmonary tuberculosis patients from negative ones in Mongolia. J Epidemiol 1998;8:90–3. [20] Jarvis NT. Rheumatic fever. Prim Care Update Obstetr Gynaecol 2003;10:9–13. [21] John S, Ravikumar E, John CN, Bashi VV. 25-year experience with 456 combined mitral and aortic valve replacement for rheumatic heart disease. Ann Thorac Surg 2000;69:1167–72. [22] World Health Organization (WHO). WHO programme for the prevention of rheumatic fever/rheumatic heart disease in 16 developing countries report from Phase I (1986–1990). WHO Cardiovascular Diseases Unit and Principal Investigators. Bull World Health Organ 1992;70:213–8. [23] Zhou L-Y, Lu K. Inflammatory valvular prolapse produced by acute rheumatic carditis: echocardiographic analysis of 66 cases of acute rhumatic carditis. Int J Cardiol 1997;58:175–8. [24] Steinhoff MC, Khalek MK, Khallaf N, et al. Effectiveness of clinical guidelines for the presumptive treatment of streptococcal pharyngitis in Egyptian children. Lancet 1997;350:918–21. [25] Zaman MM, Rouf MA, Haque S, et al. Does rhumatic fever occur usually between the ages of 5 and 15 years. Intern J Cardiol 1998;66:17–21. [26] Bayasgalan B. Determinants of infant and child mortality in Mongolia. Mong J Demogr 1996;1:12–26.
Comparison of electrocardiogram findings and lifestyles between urbanized people and ger-living people in Ulaanbaatar, Mongolia Fumio Komatsu a,∗ , Kyoko Hasegawa a , Sanae Watanabe a , Terue Kawabata a , Yoshiko Yanagisawa a , Yoshinori Kaneko a , Shigeji Miyagi a , Mitsuru Sakuma a , Yasuo Kagawa a , Chimedregzen Ulziiburen b , Luvsanbasaryu Narantuya b a
High-Technology Research Group C, Kagawa Nutrition University, 3-9-21 Chiyoda, Sakodo, Saitama 350-0288, Japan b Public Health Institute, Ulaanbaatar, Mongolia Received 20 August 2003; accepted 5 March 2004 Available online 8 May 2004
Abstract In Ulaanbaatar, lifestyles differ between urbanized people (group A) and ger (tent)-living people (group B). Group A earn high annual incomes and live in houses or apartments. Group B (who had moved to Ulaanbaatar from nomadic areas) earn low incomes and live in narrow gers. In 2002, we investigated daily food intake, health status, and electrocardiogram (ECG) in these groups. In total, 256 subjects (group A, 142; group B, 114) were enrolled. Group A ate meat, vegetables, and fruits high enough by a Western style. Group B consumed meat but ate only small amounts of vegetables and fruits. They took a lot of fat, however, the serum lipid levels of them were not so high. The fat source as energy was plant oil for cooking rather than meat. Several abnormal ECG findings including left ventricular hypertrophy (LVH) were found in 32 (22.5%) of group A and 50 (43.9%) of group B (P < 0.001). LVH was also found more in group B than in group A. LVH in group A males was accompanied by high body weight (BW), hypertension, and high LDL-cholesterol, whereas LVH in group B males seemed to be related to an unbalanced diet, high salt intake, smoking, and some low socio-economic problems. In order to promote health condition, such risk factors should securely be eliminated from the lifestyles. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Mongolia; ECG; Lifestyle; Urbanized people; Ger-living people
1. Introduction Human health and life span are generally affected by lifestyles. Mongolia has a population of 2 410 000, with mean average life span in 2002 being 64.4 years for males and 67.3 years for females, and infant mortality being 34.1/1000 [1]. In Japan, mean average life span in 2002 was 77.9 years for males and 84.7 years for females, and infant mortality was 4.2/1000 [2]. Recently, Swinburn [3] surveyed Mongolian health conditions, and found that the prevalence of non-communicable diseases such as hypertension, stroke, ischemic heart disease, and diabetes mellitus are increasing in Mongolians. In Ulaanbaatar, the ∗ Corresponding author. Tel.: +81-49-282-3702; fax: +81-49-284-6410. E-mail address: [email protected] (F. Komatsu).
capital of Mongolia, living environments and lifestyles differ between urbanized people (group A) and ger (tent)-living people (group B). The people of group A earn high annual incomes and live in houses or apartments in the central area of Ulaanbaatar. Meanwhile, the people of group B (who had moved to Ulaanbaatar from nomadic areas) earn low incomes and live in traditional tents on the outskirts of Ulaanbaatar. In 2002, we investigated daily food intake, health status, and electrocardiogram (ECG) in these groups and found several differences between them. In particular, we noticed that abnormal ECG findings including left ventricular hypertrophy (LVH) were more prevalent in group B than in group A. In this report, we describe the ECG findings and the results of daily food investigations, anthropometric measurements, and serum lipid analyses, which may be related to these ECG abnormalities.
0021-9150/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2004.03.005
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2. Methods
2.4. ECG examination
2.1. Subjects
ECG examination was performed by medical doctors and well-trained laboratory technicians. The Cardiofax 9120 ECG apparatus (Nippon Koden Co., Tokyo, Japan) was used. LVH was diagnosed if the subjects had RV5 + SV1 4.0 mV and other following findings; left atrium overload, right and left bundle branch blocks, left axial deviation, ST depression, and decreased T wave. Tall R wave alone in thin subjects was not considered to indicate LVH. Statistical significance was calculated by the χ2 -test and Student’s t-test, and P < 0.05 was considered to indicate significant difference.
A total of 256 subjects (group A, 142; group B, 114), ranging in age from 25 to 75 years, were enrolled. These subjects were healthy at the time of examination, although some had been medicated. In order to observe living environments, we visited some representative houses, apartments, and gers. Informed consent was obtained from all subjects. 2.2. Investigation of daily food intake Daily food intake was investigated using the Food Frequency Questionnaire method. All subjects were interviewed by well-trained native food specialists using the time from 30 to 45 min for each subject. In order to confirm the quantities, pictures, and photos of pan; pot, ladle, and dish were shown to the subjects. The specialists calculated a total of daily food intake using the Standard Tables of Food Composition in Mongolia [4]. 2.3. Anthropometric measurements and serum lipid analyses Blood pressure (BP), body weight (BW), body mass index (BMI), and percent body fat (%BF) were measured. BMI (kg/m2 ) were calculated from the measurements of minimal waist circumference and maximal hip circumference. %BF was indicated using a bioelectrical impedance meter (TBF-110, Tanita Co., Tokyo, Japan). Handgrip power was also measured using a handgrip meter (Type 6103, Tanita Co.). Blood samples were obtained, frozen for storage, and transported to Tokyo. Serum lipid levels were assayed at a commercial laboratory (SRL Inc., Tokyo, Japan). Total cholesterol was assayed by a cholesterol oxidation method, HDL-cholesterol by a selective inhibition test, and LDL-cholesterol and triglyceride by enzyme methods.
3. Results 3.1. Ages, monthly incomes and environments of group A and group B (1) The subjects were members of husband/wife couples. Mean average age was 49.8 ± 14.2 years for group A males (n = 71, mean ± S.D.), 49.7 ± 14.3 years for group B males (n = 57), 47.2 ± 13.1 years for group A females (n = 71), and 47.2 ± 13.2 years for group B females (n = 57). There were no inter-group differences in age for males or females. As shown in Fig. 1, the subjects were divided into 10-year age groups. There was roughly equal distribution among these 10-year age generations. (2) Mean average monthly income for one couple was as follows: group A, 158 605.6 ± 152 770.9 Tugrug (n = 71, mean ± S.D.); group B, 67 828.3 ± 30 784.5 Tugrug (n = 57). Group A people earned significantly higher monthly incomes than group B people (P < 0.01). Group B people generally worked hard as physical laborers. (3) Group A people lived in comfortable houses or modern apartments in the central area of Ulaanbaatar, and their
Fig. 1. The number of subjects in 10-year age groups.
F. Komatsu et al. / Atherosclerosis 175 (2004) 101–108
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Table 1 The daily intake of foods in groups A and B Group A (n = 142) Mean ± S.D. (g) Rice White bread Black bread Black flour Noodle Potato Meat and meat products Egg Fish Vegetable Fruit Milk and dairy products Fat Sugar Salt for cooking Green tea Black tea Vodka Total
67.2 102.7 12.2 5.7 20.2 94.9 193.9 15.5 9.4 226.2 152.5 280.0 37.7 11.6 3.2 329.7 133.4 8.5
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
50.4 63.0 23.7 24.7 27.3 57.0 100.3 21.0 18.2 184.3 179.8 237.1 56.5 15.7 1.9 241.7a 161.4 17.4
Group B (n = 114) Mean ± S.D. (kcal) 232 243 25 19 71 84 353 24 10 72 72 174 339 46 0 16 1 17 1801
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
Mean ± S.D. (g)
174 149 49 84 96 50 183 33 20 59 85 147 508 63 0 12 2 35 1747
50.5 85.9 2.5 14.8 8.9 70.1 168.5 4.4 4.6 108.1 59.4 244.0 62.7 9.6 5.9 459.0 37.7 9.7
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
33.1 61.0 6.7 35.1 10.9 50.0 79.1 7.8 11.4 83.3 86.1 208.7 77.3 10.9 9.9 337.3a 85.7 20.2
Mean ± S.D. (kcal) 174 204 5 50 31 62 307 7 5 35 28 151 564 38 0 23 0 19 1703
± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
∗∗
114 145 14 120 38 44 144 12 13 27 40 129 695 43 0 17 1 40 1636
∗ ∗∗∗ ∗ ∗∗∗ ∗∗ ∗ ∗∗∗ ∗ ∗∗∗ ∗∗∗ ∗∗ ∗∗ ∗∗∗ ∗∗∗
All values are given as mean ± S.D. Money spent for foods: group A, # ± 12793.3 and group B, # ± 9114.4 (P < 0.01). a Values are expressed in ml. ∗ P < 0.05. ∗∗ P < 0.01. ∗∗∗ P < 0.001.
families comprised three to five members. They drank public service water and used flush toilets. Meanwhile, group B people lived in narrow gers on the outskirts of Ulaanbaatar, with 8–12 people per family. They drank water from a well (one well was located in the center of each ger settlement), and used a drop hole toilet with night-soil collection. 3.2. Daily intake of foods, salt and alcohol, and smoking The results of investigation of daily intake of foods in group A and group B are shown in Table 1. Group A people generally took significantly higher amounts of the foods than group B people. Group A people consumed higher total
calories than group B people, although the difference was not significant (group A people, 1801 ± 1747 kcal; group B people, 1703 ± 1636 kcal). Money spent for foods was 15 162.9 ± 12 793.3 Tugrug per month in group A and 10 118.6 ± 9114.4 Tugrug per month in group B, the difference being significant (P < 0.01). Group A people routinely took a Western style diet and ate sufficient amounts of meat, vegetables, and fruits. Meanwhile, group B people took a traditional-style diet. They consumed meat but ate only small amounts of vegetables and fruits because the vegetables and fruits are imported from China and are expensive for them. Group B people took a higher amount of fat than group A people as shown in Table 1 (P < 0.01). In Table 2, the percentages of protein, fat, and carbohydrate, and the sources of the fat were shown. The percentage of fat in daily calories
Table 2 The energy percentage of protein, fat, and carbohydrate and fat sources in groups A and B Group A (n = 142)
Protein Fat Carbohydrate Fat source Meat Fish Plant oil
Group B (n = 114)
Mean ± S.D. (g)
Mean ± S.D. (kcal)
Percentage
Mean ± S.D. (g)
Mean ± S.D. (kcal)
Percentage
78 ± 62 63 ± 54 230 ± 177
312 ± 248 567 ± 486 920 ± 708
17.3 31.5 51.2
65 ± 43 84 ± 65 172 ± 108
260 ± 172 756 ± 585 688 ± 432
15.3 44.4 40.3
35 ± 31 1.8 ± 2.2 25 ± 33
353 ± 183 10 ± 20 339 ± 508
50 1 49
22 ± 35 0.2 ± 0.7 61 ± 78
307 ± 144 5 ± 13 564 ± 695
35 1 64
All values are given as mean ± S.D. ∗∗ P < 0.01.
∗∗ ∗∗ ∗∗ ∗∗ ∗∗
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was higher in group B than in group A. Group B people took the fat energy from plant oil for cooking rather than from meat. Furthermore, group B people used salt exceedingly. Daily salt usage for cooking in group B was larger volume than that in group A as shown in Table 1 (P < 0.01). Group B males routinely drank vodka, which has a very high alcohol percentage, whereas group A people preferred whisky to vodka. But there was no difference in the volume of alcohol consumed between these groups. Most group B males were smokers, and one-fourth of group A males were smokers. 3.3. Anthropometric measurements The height of the subjects was as follows: group A males, 168.3 ± 4.8 cm; group B males, 166.3 ± 4.5 cm; group A females, 155.8 ± 4.7 cm; and group B females, 153.7 ± 4.4 cm. Both males and females in group A (P < 0.05) were significantly taller in the height than those in group B (P < 0.05). Mean averages of systolic blood pressure, body weight, body mass index, and percent body fat are shown in Fig. 2. There was no significant difference in systolic BP between
these groups. But group A males demonstrated significantly higher BW, BMI, and %BF than group B males. Handgrip power was 41.7 ± 9.3 kg for group A males, 37.1 ± 6.4 kg for group B males, 27.1 ± 5.9 kg for group A females, and 24.0 ± 5.9 kg for group B females. There were significant differences between both males (P < 0.05) and females (P < 0.05). The handgrip power was also compared among high-age subjects (age 45 years). It was 38.8 ± 9.9 kg for group A males, 34.3 ± 5.5 kg for group B males, 25.4 ± 5.4 kg for group A females, and 22.0 ± 5.3 kg for group B females. There were significant differences between both males (P < 0.05) and both females (P < 0.05). This finding suggests that aging may progress faster in group B than in group A. 3.4. Serum lipid levels The serum levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride are shown in Fig. 3. With the exception of triglyceride in females, there were no significant differences between groups A and B. There were no apparent gender differences. As shown in Tables 1 and 2, although group B people took a higher amount of daily fat than group A people, the serum lipid levels were not so high.
Fig. 2. The levels of systolic blood pressure (BP), body weight (BW), body mass index (BMI), and percent body fat (%BF) in groups A and B (group A: male, 71; female, 71 and group B: male, 57; female, 57. Mean ± S.D., ∗∗ P < 0.01).
F. Komatsu et al. / Atherosclerosis 175 (2004) 101–108
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Fig. 3. The levels of total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride (group A: male, 71; female, 71 and group B: male, 57; female, 57. Mean ± S.D., ∗ P < 0.05).
3.5. ECG examination (1) Some of the subjects showed several abnormal ECG findings. They had two or three changes such as LVH, sinus bradycardia, overload of left atrium, PR shortness, supra-ventricular and ventricular premature contractions, atrial fibrillation, atrio-ventricular block, left and right bundle branch blocks, intraventricular conduction disturbance, ST elevation, ST depression, tall T wave, flat T wave, and negative T wave. These abnormal findings were observed in 32 (22.5%) of group A and 50 (43.9%) of group B people. Frequency of them was higher in group B than in group A (P < 0.001). (2) Relationship between the ECG abnormalities and age is shown in Table 3. Incidence of the abnormalities increased with age. They were found in 18/71 (25.4%) of group A males, 33/57 (57.9%) of group B males, 14/71 (19.7%) of group A females, and 17/57 (29.8%) of group B females. The abnormalities were found in males more than in females. There was a significant difference between group A and B males (P < 0.001). (3) In these abnormalities, the difference of incidence of LVH was conspicuous. As shown in Table 3, LVH was
observed among high-age subjects (age 45 years): group A males, 3/71 (4.2%); group B males, 11/57 (19.3%); group A females, 0/71; and group B females, 4/57 (7.0%). For males, there was a significant difference (P < 0.01). (4) Because LVH was observed among high-age subjects (in particular in males), we compared the anthropometric measurements and serum lipid levels between the LVH males and normal-ECG males (age 45 years). As shown in Tables 4 and 5, LVH in group A males was accompanied by hypertension, high BW, and high LDL-cholesterol level. However, LVH in group B males was not always accompanied by such findings. The LVH males of group B showed a wide range of BP: some had hypertension and others had normal BP. They were relatively low BW and low %BF. Furthermore, they showed low LDL-cholesterol compared to the LVH males of group A. These findings suggest that in group A males, LVH may be related to high BW, hypertension, and high LDL-cholesterol, whereas there is no such apparent relationship in group B males. LVH in group B males may be connected with unbalanced diet, high salt intake, smoking, and other factors.
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Table 3 The number of abnormal ECG findings in each generation Age
Group A, males
Group B, males
Group A, females
Group B, females
Total
Abnormal
Total
Abnormal
Total
Abnormal
Total
Abnormal
Abnormal ECG 25–34 12 35–44 18 45–54 11 55–64 17 65–75 13 Total 71 Age Total
2 2 0 7 7 18 (25.4)∗∗∗ LVH
11 12 11 14 9 57 Total
3 3 9 13 5 33 (57.9)∗∗∗ LVH
15 17 19 11 9 71 Total
1 2 6 3 2 14 (19.7) LVH
12 14 13 13 5 57 Total
0 2 8 3 4 17 (29.8) LVH
LVH 25–34 35–44 45–54 55–64 65–75 Total
0 0 0 2 1 3 (4.2)∗∗
11 12 11 14 9 57
0 0 3 6 2 11 (19.3)∗∗
15 17 19 11 9 71
0 0 0 0 0 0 (0)
12 14 13 13 5 57
0 0 1 1 2 4 (7.0)
12 18 11 17 13 71
Values in parenthesis are in percentage. ∗∗ P < 0.01. ∗∗∗ P < 0.001. Table 4 The levels of systolic blood pressure, body-weight, and body mass index (BMI) and percent body fat (%BF) of the LVH males and normal-ECG males (age 45 years) Parameter
Group
Finding
n
Mean ± S.D.
Blood pressure (mmHg)
A
Normal-ECG
53
127.7 ± 18.6]∗∗
LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH
3 24 11 53 3 24 11 53 3 24 11 53 3 24 11
169.0 123.6 157.5 66.9 73.3 61.9 58.9 25.6 25.5 22.3 22.4 29.2 28.9 22.6 22.6
B Body weight (kg)
A B
BMI
A B
%BF
A B
± ± ± ± ± ± ± ± ± ± ± ± ± ± ±
3.6]∗∗ 21.5]∗∗ 24.9 14.1]∗ 7.1]∗∗ 13.1 7.2 3.7]∗∗ ]∗∗ 1.2 4.1 3.1 8.1]∗∗ ]∗ 2.4 9.3 6.5
were generally hard workers. Group B people drank water from a well and used drop hole toilets. In 2002, the Japan International Cooperation Agency (JICA) reported that Ulaanbaatar had been fully equipped with water works and sewerage systems [5] but the living environments that we observed in the ger settlement differed from that assessment. Group A people consumed high amounts of foods compared to group B people. Money spent for foods was greater in group A than in group B. Group A people took a Western-style diet and ate meat, vegetables, and fruits high enough. Whereas, group B people consumed meat but
Table 5 The levels of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglyceride of the LVH males and normal-ECG males (age 45 years) Parameter
Group
Finding
n
Mean ± S.D.
Total cholesterol (mg/dl)
A
Normal-ECG
53
186.2 ± 34.2
LVH Normal-ECG LVH Normal-ECG
3 24 11 53
216.0 178.2 175.4 54.4
± ± ± ±
6.6]∗ 31.0 31.9 11.5
LVH Normal-ECG LVH Normal-ECG
3 24 11 53
55.7 54.7 56.9 116.3
± ± ± ±
4.0 11.5 14.8 30.6
LVH Normal-ECG LVH Normal-ECG LVH Normal-ECG LVH
3 24 11 53 3 24 11
146 107.8 104.7 109.5 106.7 113.2 99.2
± ± ± ± ± ± ±
3.6]∗ ]∗ 25.7 25.2 65.3 39.8 145.6 86.5
∗
P < 0.05. ∗∗ P < 0.01.
B HDL-cholesterol (mg/dl)
4. Discussion In this study, we investigated the lifestyles, daily food intake, health status, and ECG findings in urbanized people (group A) and ger-living people (group B) of Ulaanbaatar, and found several differences between these two groups. The main reason of differences was considered to be due to socio-economic conditions. Group A people earned high monthly incomes and lived in comfortable houses or modern apartments but group B people earned only low incomes and lived in narrow gers with many family members. They
A
B LDL-cholesterol (mg/dl)
A
B Triglyceride (mg/dl)
A B
∗
P < 0.05.
F. Komatsu et al. / Atherosclerosis 175 (2004) 101–108
ate only small amounts of vegetables and fruits. Group B people took a lot of fat. The percentage of fat in daily calories of this group was very high. They took the fat energy from plant oil for cooking rather than from meat. This food style was different from that of group A people. Group A people used 3.2 g of salt for cooking and group B people used 5.9 g. In Japanese, salt usage for cooking is 1.2 g [6]. This finding indicates that the inhabitants in Ulaanbaatar, particularly group B people, use high quantities of salt for cooking. Recent nutritional research in Mongolia reported that total daily salt intake in Mongolian is 16.7 g [7], which is very high compared to Japanese, where it is 12.3 g [6]. Theses diet styles may affect to the health status. Group B males had lower BW, lower BMI, and lower %BF than group A males. Furthermore, group B people showed lower handgrip power than group A people. The difference increased with age. Aging may progress faster in group B than in group A. We also compared serum lipid levels between these groups. With the exception of triglyceride in females, we found no significant differences in the serum lipid levels between these two groups. Although group B people took a high amount of daily fat, they demonstrated not so high levels. Concerning the total cholesterol, group A males showed 186.8 mg/dl; group B males, 184.9 mg/dl; group A females, 188.6 mg/dl; and group B females, 185.7 mg/dl. In Japanese adults (age 20 years), mean average total cholesterol level is 198.0 mg/dl for males and 203.7 mg/dl for females [6]. It is conspicuous that Mongolians including both groups A and B are in low total cholesterol compared to Japanese. The reason is unknown. Previously, Shaper et al. [8] surveyed the serum lipids of the Samburu tribe people in Northern Kenya because these nomadic people took a diet consisting almost entirely of milk, meat, and animal blood of cattle and camels. They found that the people did show no increase in cholesterol level, no rise in blood pressure, or no prevalence of ischemic heart disease. Thus, they speculated that the low serum lipid might be related with a high degree of their physical activities. In Mongolians, in particular in group B people, the physical activity (hard labor) may be one of the reasons of low serum lipids. But such low levels of serum lipids do not seem to be explained by the physical activity alone. It is known that Pima Indians in Arizona, USA, also show low cholesterol levels despite high intake of saturated fat [9,10]. Both Mongolians and Pima Indians may utilize efficient hepatic clearance of cholesterol into bile [3]. It would be interesting to know whether or not Mongolians and Pima Indians have the same ancestor in spite of very far distance between these two areas. In this study, we performed ECG examination in the subjects and found several abnormal ECG findings at a high frequency. Concerning the ECG examination, there are some reports. Olziikhutag and Danilov [11] performed ECG examination in 1357 aboriginal males of Mongolia and found nonspecific changes in T wave and ST segment at a frequency of 14.6–21.9%. They considered that the nonspecific
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myocardial changes might be due to cold as well as altitude factor. Manaseki [12] also stated that ischemic heart diseases were common in Mongolia. Recently, Swinburn [3] surveyed Mongolian health conditions and found that hypertension, stroke, ischemic heart disease, and diabetes mellitus are prevalent in Mongolians and reported that the high prevalence of them may be due to the lifestyles of the people. In the present study, in particular, we compared the prevalence of abnormal ECG findings between groups A and B. It is very interesting because the precise comparison of it between the urbanized people and ger-living people had not been reported. The abnormalities including LVH were recognized with a greater frequency in group B than in group A. As the reasons, we should consider many things such as economic condition, living environments, daily diet, smoking, hard labor, and others. Of course, because group B people had lived in nomadic areas before they moved to Ulaanbaatar, their heart might have already been influenced by the cold temperature as described by Olziikhutag and Danilov [11]. The temperature decreases to −40 ◦ C in winter. The severe climate may affect to the heart function of them. In this discussion, we mention about the mechanisms of LVH. Although LVH is caused by several mechanisms, the following three mechanisms may be important: (a) high body weight → hypertension → LVH, (b) high salt intake and smoking → hypertension and arteriosclerosis → LVH, and (c) infection → endocarditis → heart valve disease → LVH. Mechanism (a): high body weight often induces hypertension. The hypertension imposes a load on the left ventricle resulting LVH. High body weight is often accompanied by hypercholesterolemia, which induces atherosclerosis, LVH, and chronic heart diseases [13]. Nasyrov et al. [14] stated that in Russia, prevalence of myocardium and coronary heart diseases was about 3.5 times higher in people who were hypertensive and overweight, and was 2–2.5 times higher in people with hypercholesterolemia. High body weight, hypercholesterolemia, and hypertension may be due to Western-style diet. For three decades, Western-style diets have also been popular among Japanese people, many of whom now exhibit such unhealthy status [6]. In group A males, LVH was accompanied by high body weight, hypertension, and high LDL-cholesterol in spite of low cholesterolemia in Mongolians. This suggests that LVH in group A males is caused by mechanism (a). Mechanism (b): hypertension and arteriosclerosis are often induced by high salt intake [15,16] and smoking. Group B people consumed a high-salt diet, and most males of group B were smokers. Prolonged smoking contributes to hypertension, LVH, stroke, and ischemic heart diseases [17,18]. In the present study, LVH was observed in males more frequently than in females; this may be related to the smoking, drinking, and hard labor. Thus, LVH in group B may be due to mechanism (b), although the mechanism (a) may also be involved in part. Mechanism (c): LVH is also connected with heart valve disease, which is often caused by bacterial infection. In
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Mongolia, several infections are prevalent [19]. Betahemolytic streptococcus infection is one of them. Drinking of well water and using of drop hole toilets may be related with this infection. This infection often causes rheumatic fever (RF) and endocarditis, and then heart valve disease and LVH after 20–30 years. RF is rare in developed countries. However, it still remains endemic in many developing countries, particularly in Asia and Africa [20,21]. Prevalence of RF is connected with low socio-economic status. The World Health Organization (WHO) [22] surveyed the prevalence of rheumatic fever and rheumatic heart disease in 16 developing countries and found a high prevalence in Asian, African, and Eastern Mediterranean regions. Rheumatic heart disease is a serious cause of morbidity and mortality in developing countries [23–25]. According to these previous reports, we speculate that some of the LVH in group B may be due to mechanism (c) such as rheumatic heart valve disease. We further speculate that rheumatic heart disease may affect the life span in this group because it is known that mortality is high in tent-living people [26]. However, in the present investigation, we did not confirm the heart valve disease using an X-ray photo or an ultrasonic generator because the high prevalence of LVH was noticed after the data were collected. Assessment of the prevalence of heart valve disease may shed further light on the present findings. In conclusion, in the present study, we found several abnormal ECG findings including LVH at a high frequency. Group A people are in a high risk condition of LVH due to high body weight, hypertension, and high LDL-cholesterol, which may be connected with a Western style diet. Whereas, group B people need to correct their unbalanced diet, high salt intake, smoking, hard labor, and others. We also propose that high frequency of LVH may be related to the incomplete treating of streptococcus infection and RF in the early stage. In order to promote health status, such risk factors should securely be eliminated from the lifestyles.
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