Vol. 19, No. 2 Printed in Great Britain
International Journal of Epidemiology ©International Epidemiological Association 1990
Twenty-Year Stroke Mortality and Prediction in Twelve Cohorts of the Seven Countries Study A MENOTTI, 1 A KEYS,2 H BLACKBURN,2 C ARAVANIS,' A DONTAS, 4 F F1DANZA,5 S GIAMPAOU, 1 M KARVONEN,' D KROMHOUT, 7 S NEDELJKOVIC,' A NISSINEN,* J PEKKANEN,10 S PUNSAR,11 FSECCARECCIA1 AND H TOSHIMA"
multinational level, any single paper on the epidemiology of stroke, whereas some papers have appeared at national level.6"8 Part of the reason for this was the lesser interest in stroke and the uncertainties about the diagnostic criteria of non-fatal cases which were not properly developed in the early stages of the study. However, the availability of long-term mortality data, at least in the majority of the enrolled cohorts, led recently to the opportunity to review this aspect of the study.
Epidemiology of stroke has been analysed in some of the epidemiological longitudinal population studies started in the 1950s and 1960s originally targeted at the study of coronary heart disease. This was the case of the Framingham study1"2 and of the Seven Countries Study.3"5 The latter in particular, did not produce, at ' Laboratory of Epidemiology and Biostatistics, Istituto Superiore di Sanaa', Viale Regina Elena 299, 1-00161 Rome, Italy. 'Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, Minn, USA. 3 Athens Medical Center, Athens, Greece. 4 Athens Home for the Aged Research Center, Athens, Greece. 3 Institute of Nutrition Science, University of Perugia, Perugia, Italy. 'Pioppi, SA, Italy. 7 Department of Epidemiology, National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands. 1 Intema Klinika B, University of Belgrade, Belgrade, Yugoslavia. * Department of Community Medicine and Genera] Practice, University of Kuopio, Kuopio, Finland. "Department of Epidemiology, National Public Health Institute, Helsinki, Finland. " Espoo, Finland. 12 Third Department of Medicine, University of Kurume, Kurume, Japan.
MATERIALS AND METHODS The Seven Countries Study on cardiovascular diseases was started in the late 1950s and enrolled 16 cohorts of men aged 40-59, in USA (one cohort), Finland (two cohorts), the Netherlands (one cohort), Italy (three cohorts), Yugoslavia (five cohorts), Greece (two cohorts) and Japan (two cohorts) for a total of 12 743 3.4
men. East and West Finland, Crevalcore and Montegjorgio in Italy, Dalmatia, Slavonia, Velika, Krsna and Zrenjanin in Yugoslavia, Corfu and Crete in Greece 309
Downloaded from http://ije.oxfordjournals.org/ at University of Saskatchewan on July 19, 2015
Menotti A (Laboratory of Epidemiology and Biostatistics, Istituto Superiore di SanitS, 1-00161, Rome, Italy), Keys A, Blackburn H, Aravanis C, Dontas A, Fidanza F, Giampaoli S, Karvonen M, Kromhout D, Nedeljkovic S, Nissinen A, Pekkanen J, PunsarS, Seccareccia FandToshima H. Twenty-year stroke mortality and prediction in twelve cohorts of the Seven Countries Study. Internationa/Journal of Epidemiology 1990; 19: 309-315. Twelve cohorts of men aged 40-59 for a total of 8287 individuals in six countries (Finland, the Netherlands, Italy, Yugoslavia, Greece and Japan) were examined in the late 1950s or early 1960s for the measurement of some risk factors and then followed up for mortality and causes of death through 20 years. Large differences in 20-year death rates from stroke were recorded among cohorts, with the highest levels in the pool of the Yugoslavia (67 per 1000) and Japanese cohorts (62 per 1000) and the lowest in the Dutch cohort (22 per 1000). The simple linear correlation (among cohorts) of stroke mortality on mean levels at entry of some factors showed inverse significant coefficients for systolic (-0.63) diastolic (-0.51) and mean blood pressure (-0.72), and for serum cholesterol (-0.72), whereas no significant coefficients were found for mean body mass index, mean cigarette consumption and mean physical activity. The Cox model solved for six national pools of cohorts showed that only age and mean blood pressure carry significant positive coefficients, whereas all the other available factors (cigarette consumption, serum cholesterol, body mass index, physical activity) did not approach significant levels except the negative coefficients of smoking habits in Greece.
310
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
•
o o o
rr
—age (AGE) in years, rounded off at the nearest birthday; —body mass index (BMI) expressed as weight (kg)/ height (m)2; —cigarette smoking (CIG), as elicited by a questionnaire, expressed in number of cigarettes currently smoked per day; —serum cholesterol (CHOL) in mg/dl, and mmol/1, measured on a casual blood sample following the method of Abell-Kendal as modified by Anderson and Keys;9 —physical activity related to work, (PHYAC) elicited from a questionnaire and matching the answers with the reported type of work; three levels have been considered, ie, l=sedentary; 2=moderate; 3= heavy; —mean blood pressure (MBP) in mm/Hg, derived from diastolic (DBP) plus one-third of the difference between systolic (SBP) and diastolic blood pressure; the blood pressure was taken by a mercury sphygmomanometer in supine position at the end of a physical examination, by trained doctors following the methodology later described in the WHO
70
•
LU Q.
W
1 I Q LU
s to
60
-
•
• •
SO
-
40
-
•
• •
.
30
-
20
-
10
-
0
- AAAA
• •
90
95
100
106
110
MEAN BLOOD PRESSURE mmHg FIGURE 1.
The relationship between mean blood pressure and death rates from stroke in 12 cohorts.
(r=—0.72;p
International Journal of Epidemiology ©International Epidemiological Association 1990
Twenty-Year Stroke Mortality and Prediction in Twelve Cohorts of the Seven Countries Study A MENOTTI, 1 A KEYS,2 H BLACKBURN,2 C ARAVANIS,' A DONTAS, 4 F F1DANZA,5 S GIAMPAOU, 1 M KARVONEN,' D KROMHOUT, 7 S NEDELJKOVIC,' A NISSINEN,* J PEKKANEN,10 S PUNSAR,11 FSECCARECCIA1 AND H TOSHIMA"
multinational level, any single paper on the epidemiology of stroke, whereas some papers have appeared at national level.6"8 Part of the reason for this was the lesser interest in stroke and the uncertainties about the diagnostic criteria of non-fatal cases which were not properly developed in the early stages of the study. However, the availability of long-term mortality data, at least in the majority of the enrolled cohorts, led recently to the opportunity to review this aspect of the study.
Epidemiology of stroke has been analysed in some of the epidemiological longitudinal population studies started in the 1950s and 1960s originally targeted at the study of coronary heart disease. This was the case of the Framingham study1"2 and of the Seven Countries Study.3"5 The latter in particular, did not produce, at ' Laboratory of Epidemiology and Biostatistics, Istituto Superiore di Sanaa', Viale Regina Elena 299, 1-00161 Rome, Italy. 'Division of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, Minn, USA. 3 Athens Medical Center, Athens, Greece. 4 Athens Home for the Aged Research Center, Athens, Greece. 3 Institute of Nutrition Science, University of Perugia, Perugia, Italy. 'Pioppi, SA, Italy. 7 Department of Epidemiology, National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands. 1 Intema Klinika B, University of Belgrade, Belgrade, Yugoslavia. * Department of Community Medicine and Genera] Practice, University of Kuopio, Kuopio, Finland. "Department of Epidemiology, National Public Health Institute, Helsinki, Finland. " Espoo, Finland. 12 Third Department of Medicine, University of Kurume, Kurume, Japan.
MATERIALS AND METHODS The Seven Countries Study on cardiovascular diseases was started in the late 1950s and enrolled 16 cohorts of men aged 40-59, in USA (one cohort), Finland (two cohorts), the Netherlands (one cohort), Italy (three cohorts), Yugoslavia (five cohorts), Greece (two cohorts) and Japan (two cohorts) for a total of 12 743 3.4
men. East and West Finland, Crevalcore and Montegjorgio in Italy, Dalmatia, Slavonia, Velika, Krsna and Zrenjanin in Yugoslavia, Corfu and Crete in Greece 309
Downloaded from http://ije.oxfordjournals.org/ at University of Saskatchewan on July 19, 2015
Menotti A (Laboratory of Epidemiology and Biostatistics, Istituto Superiore di SanitS, 1-00161, Rome, Italy), Keys A, Blackburn H, Aravanis C, Dontas A, Fidanza F, Giampaoli S, Karvonen M, Kromhout D, Nedeljkovic S, Nissinen A, Pekkanen J, PunsarS, Seccareccia FandToshima H. Twenty-year stroke mortality and prediction in twelve cohorts of the Seven Countries Study. Internationa/Journal of Epidemiology 1990; 19: 309-315. Twelve cohorts of men aged 40-59 for a total of 8287 individuals in six countries (Finland, the Netherlands, Italy, Yugoslavia, Greece and Japan) were examined in the late 1950s or early 1960s for the measurement of some risk factors and then followed up for mortality and causes of death through 20 years. Large differences in 20-year death rates from stroke were recorded among cohorts, with the highest levels in the pool of the Yugoslavia (67 per 1000) and Japanese cohorts (62 per 1000) and the lowest in the Dutch cohort (22 per 1000). The simple linear correlation (among cohorts) of stroke mortality on mean levels at entry of some factors showed inverse significant coefficients for systolic (-0.63) diastolic (-0.51) and mean blood pressure (-0.72), and for serum cholesterol (-0.72), whereas no significant coefficients were found for mean body mass index, mean cigarette consumption and mean physical activity. The Cox model solved for six national pools of cohorts showed that only age and mean blood pressure carry significant positive coefficients, whereas all the other available factors (cigarette consumption, serum cholesterol, body mass index, physical activity) did not approach significant levels except the negative coefficients of smoking habits in Greece.
310
INTERNATIONAL JOURNAL OF EPIDEMIOLOGY
•
o o o
rr
—age (AGE) in years, rounded off at the nearest birthday; —body mass index (BMI) expressed as weight (kg)/ height (m)2; —cigarette smoking (CIG), as elicited by a questionnaire, expressed in number of cigarettes currently smoked per day; —serum cholesterol (CHOL) in mg/dl, and mmol/1, measured on a casual blood sample following the method of Abell-Kendal as modified by Anderson and Keys;9 —physical activity related to work, (PHYAC) elicited from a questionnaire and matching the answers with the reported type of work; three levels have been considered, ie, l=sedentary; 2=moderate; 3= heavy; —mean blood pressure (MBP) in mm/Hg, derived from diastolic (DBP) plus one-third of the difference between systolic (SBP) and diastolic blood pressure; the blood pressure was taken by a mercury sphygmomanometer in supine position at the end of a physical examination, by trained doctors following the methodology later described in the WHO
70
•
LU Q.
W
1 I Q LU
s to
60
-
•
• •
SO
-
40
-
•
• •
.
30
-
20
-
10
-
0
- AAAA
• •
90
95
100
106
110
MEAN BLOOD PRESSURE mmHg FIGURE 1.
The relationship between mean blood pressure and death rates from stroke in 12 cohorts.
(r=—0.72;p
