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Is it desirable to reduce total serum cholesterol level as low as possible?
PREVENTIVE
MEDICINE
(1979)
8, 104 - 111
LETTERS TO THE EDITOR Is it Desirable to Reduce Total Serum Cholesterol Low as Possible?
Level as
From: Hirotsuga Ueshima, Minoru Iida, and Yoshio Komachi, Department of Epidemiology and Mass Examination for Cardiovascular Diseases, The Center for Adult Diseases, Osaka, Japan Sir: It is generally believed desirable to maintain total serum cholesterol level as low as possible in order to prevent coronary heart disease (CHD). Is it also desirable to keep serum total cholesterol level as low as possible to prevent cerebral stroke? It is well known that mortality rates for CHD (1) and total serum cholesterol level (2, 3) are lower among Japanese than among people in Western countries. Japan, however, has a higher mortality rate for stroke than Western countries (1, 4). And in Japan, cerebral hemorrhage was more common than cerebral infarction until recent years (5, 6). For 10 years we have been carrying out several epidemiological studies on cerebra- and cardiovascular diseases in various populations of 6,500 men with different life-styles (7). One group, mainly farmers residing in the Akita district, had the highest incidence rate of stroke and the lowest mean level of serum cholesterol-155 mg/dl in men aged 40 to 59 years. Both groups of industrial manual workers and clerks in Osaka City had the lowest incidence rate of stroke, and their mean serum total cholesterol levels were between 180 and 200 mg/dl. A group of Csrsbral
6001
:
hemorrhage
Csrabrrl
600c
infarction
.
zYI300‘ii E 200-
;
300-
0,
i. 6,
E .-Y
F
200Kil
;
K’O
1 IOOa:
. i, OM
O150
I, 160
Serum
170
total
I1 190
cholesterol
. 0,
loo-
190
i. tic ,O 200 mp/dl
level
150 Ssrum
I
1
I
160
170
180
total
cholesterol
ii, I
190
1
200 mp/dl
level
FIG. 1. Annual incidence of cerebral strokes plotted against serum total cholesterol level (males, M-69). 104 0091-7435/79/010104-08$02.00/O Copyright 0 1979 by Academic Press, Inc. All rights of reproduction in any form reserved.
LETTERS
TO
THE
EDITOR:
CHOLESTEROL
105
executives in Osaka City who showed the highest total mean serum cholesterol level, 220 mg/dl, had the highest incidence rate of CHD among all the study groups. According to our cooperative nationwide study (8, 9), a significant negative correlation was observed between the mean serum cholesterol level and the incidence rate of stroke as shown in Fig. 1. Moreover, the results analyzed by a multivariate logistic function revealed that the serum total cholesterol level was a significant negative risk factor for cerebral hemorrhage in the Akita group. It seems that the mortality rate for stroke increases in groups with a serum total cholesterol level lower than 160 mg/dl. Such low levels of total serum cholesterol may have derived mainly from the traditional Japanese diet, i.e., poor intake of animal fat and protein. In order to prevent stroke, especially cerebral hemorrhage, it may be better to keep the level of serum cholesterol “not too low.” Our results suggest that the desirable level of total serum cholesterol in men may be somewhere between 180 and 200 mg/dl, where incidence rates of both CHD and stroke are low. REFERENCES 1. WHO. “World Health Statistics Annual, 1969,” Vol. 1: “Vital Statistics and Causes of Death.” World Health Organization, Geneva, 1972. 2. Komachi, Y., Iida, M., Shimamoto, T., Chikayama, Y., Takahashi, H., Konishi, M., and Tominaga, S. Geographic and occupational comparisons of risk factors in cardiovascular diseases in Japan. Jupan Circ. J. 35, 189-207 (1971). 3. Tominaga, S. Serum lipid metabolism in cases with cerebrovascular diseases in Japan: With special reference to serum total cholesterol and triglyceride levels. Med. J. Osaka Univ. 19, 353-368 (1967). [in Japanese] 4. WHO. “Cerebrovascular Disease: Prevention, Treatment, and Rehabilitation.” Report of WHO Meeting. World Health Organization Technical Report Series, No. 469, 1971. 5. Ozawa, H., Komachi, Y., Anzai, S., and Kawaguchi, T. Statistical observation on mortality rate for cerebral hemorrhage and cerebral infarction in Japan. Kosei no Shihyo 23, 2-51 (1976). [in Japanese] 6. Komachi, Y., Ozawa, H., Iida, M., er al. Epidemiology on stroke. Gendai Zryo 9, 545-552 (1976). [in Japanese] 7. Takahashi, H. Comparative studies on risk factors of cerebra-cardio-vascular disease in Japan: With special reference to overweight and serum lipids levels. Med. J. Osaka Univ. 26, 227-252 (1974). [in Japanese] 8. Komachi, Y., Iida, M., Ozawa, H., et al. Interrelationship of food and stroke in Japan, in “Proceedings of The Tenth International Congress of Nutrition,” p. 307, August 3-9, Kyoto, Japan, 1975. 9. Komachi, Y., Iida, M., Ozawa, H., er al. Interrelationship of food and stroke in Japan. Annu. Rep. Center Aduli Dis. 15, 82-93 (1975).
MEDICINE
(1979)
8, 104 - 111
LETTERS TO THE EDITOR Is it Desirable to Reduce Total Serum Cholesterol Low as Possible?
Level as
From: Hirotsuga Ueshima, Minoru Iida, and Yoshio Komachi, Department of Epidemiology and Mass Examination for Cardiovascular Diseases, The Center for Adult Diseases, Osaka, Japan Sir: It is generally believed desirable to maintain total serum cholesterol level as low as possible in order to prevent coronary heart disease (CHD). Is it also desirable to keep serum total cholesterol level as low as possible to prevent cerebral stroke? It is well known that mortality rates for CHD (1) and total serum cholesterol level (2, 3) are lower among Japanese than among people in Western countries. Japan, however, has a higher mortality rate for stroke than Western countries (1, 4). And in Japan, cerebral hemorrhage was more common than cerebral infarction until recent years (5, 6). For 10 years we have been carrying out several epidemiological studies on cerebra- and cardiovascular diseases in various populations of 6,500 men with different life-styles (7). One group, mainly farmers residing in the Akita district, had the highest incidence rate of stroke and the lowest mean level of serum cholesterol-155 mg/dl in men aged 40 to 59 years. Both groups of industrial manual workers and clerks in Osaka City had the lowest incidence rate of stroke, and their mean serum total cholesterol levels were between 180 and 200 mg/dl. A group of Csrsbral
6001
:
hemorrhage
Csrabrrl
600c
infarction
.
zYI300‘ii E 200-
;
300-
0,
i. 6,
E .-Y
F
200Kil
;
K’O
1 IOOa:
. i, OM
O150
I, 160
Serum
170
total
I1 190
cholesterol
. 0,
loo-
190
i. tic ,O 200 mp/dl
level
150 Ssrum
I
1
I
160
170
180
total
cholesterol
ii, I
190
1
200 mp/dl
level
FIG. 1. Annual incidence of cerebral strokes plotted against serum total cholesterol level (males, M-69). 104 0091-7435/79/010104-08$02.00/O Copyright 0 1979 by Academic Press, Inc. All rights of reproduction in any form reserved.
LETTERS
TO
THE
EDITOR:
CHOLESTEROL
105
executives in Osaka City who showed the highest total mean serum cholesterol level, 220 mg/dl, had the highest incidence rate of CHD among all the study groups. According to our cooperative nationwide study (8, 9), a significant negative correlation was observed between the mean serum cholesterol level and the incidence rate of stroke as shown in Fig. 1. Moreover, the results analyzed by a multivariate logistic function revealed that the serum total cholesterol level was a significant negative risk factor for cerebral hemorrhage in the Akita group. It seems that the mortality rate for stroke increases in groups with a serum total cholesterol level lower than 160 mg/dl. Such low levels of total serum cholesterol may have derived mainly from the traditional Japanese diet, i.e., poor intake of animal fat and protein. In order to prevent stroke, especially cerebral hemorrhage, it may be better to keep the level of serum cholesterol “not too low.” Our results suggest that the desirable level of total serum cholesterol in men may be somewhere between 180 and 200 mg/dl, where incidence rates of both CHD and stroke are low. REFERENCES 1. WHO. “World Health Statistics Annual, 1969,” Vol. 1: “Vital Statistics and Causes of Death.” World Health Organization, Geneva, 1972. 2. Komachi, Y., Iida, M., Shimamoto, T., Chikayama, Y., Takahashi, H., Konishi, M., and Tominaga, S. Geographic and occupational comparisons of risk factors in cardiovascular diseases in Japan. Jupan Circ. J. 35, 189-207 (1971). 3. Tominaga, S. Serum lipid metabolism in cases with cerebrovascular diseases in Japan: With special reference to serum total cholesterol and triglyceride levels. Med. J. Osaka Univ. 19, 353-368 (1967). [in Japanese] 4. WHO. “Cerebrovascular Disease: Prevention, Treatment, and Rehabilitation.” Report of WHO Meeting. World Health Organization Technical Report Series, No. 469, 1971. 5. Ozawa, H., Komachi, Y., Anzai, S., and Kawaguchi, T. Statistical observation on mortality rate for cerebral hemorrhage and cerebral infarction in Japan. Kosei no Shihyo 23, 2-51 (1976). [in Japanese] 6. Komachi, Y., Ozawa, H., Iida, M., er al. Epidemiology on stroke. Gendai Zryo 9, 545-552 (1976). [in Japanese] 7. Takahashi, H. Comparative studies on risk factors of cerebra-cardio-vascular disease in Japan: With special reference to overweight and serum lipids levels. Med. J. Osaka Univ. 26, 227-252 (1974). [in Japanese] 8. Komachi, Y., Iida, M., Ozawa, H., et al. Interrelationship of food and stroke in Japan, in “Proceedings of The Tenth International Congress of Nutrition,” p. 307, August 3-9, Kyoto, Japan, 1975. 9. Komachi, Y., Iida, M., Ozawa, H., er al. Interrelationship of food and stroke in Japan. Annu. Rep. Center Aduli Dis. 15, 82-93 (1975).