ArticlesBlood pressure, cholesterol, and stroke in eastern Asia
Introduction
For the past few decades, stroke has been a principal cause of death in the People's Republic of China, Japan, and other eastern Asian countries. The burden of stroke in this region is predicted to increase, both in absolute terms and as a proportion of total disease burden.1 Throughout much of eastern Asia, the pattern of stroke incidence is different from that in western Europe and North America—the incidence of both ischaemic and haemorrhagic strokes is higher, and a greater proportion of strokes are due to cerebral haemorrhage,2 the outcome of which is poor. The reasons for the greater burden of stroke in eastern Asian populations remain unclear, and direct reliable evidence about the determinants of stroke in this region is therefore needed. Such evidence is essential for prioritisation of regional stroke-prevention strategies.
Blood pressure is a key determinant of stroke risk in western populations, although few studies have investigated the separate associations of blood pressure with the risks of ischaemic and haemorrhagic stroke. Overviews of observational studies3, 4 have shown a strong, direct association between usual blood pressure and total stroke risk, and have provided precise estimates of the size of potential benefits of blood-pressure lowering in western populations. There are few data on the associations of blood cholesterol concentrations with stroke risks. In general, little association of total cholesterol with total stroke risk has been reported, but this could be the net result of a positive association with cerebral infarction and a negative association with cerebral haemorrhage.4 However, most individual studies have been too small to assess reliably the size and shape of any such associations, particularly at lower cholesterol concentrations such as those typically seen in populations from eastern Asia.
The Eastern Stroke and Coronary Heart Disease Collaborative Project was initiated to provide evidence about the associations of diastolic blood pressure and total cholesterol concentration with the risks of major cardiovascular disease in populations from eastern Asia. We describe here the results for stroke.
Section snippets
Identification of studies and collection of data
The minimum criteria for the inclusion of studies in this collaborative project were: a prospective, observational study of more than 500 individuals; a study population resident in eastern Asia; measurement of diastolic blood pressure at entry; and follow-up data on stroke deaths. Potentially eligible studies were identified from computerised searches, publication reference lists, conference proceedings, and discussion with researchers in the region. Collaborators provided standard tabular
Characteristics of study populations
18 cohort studies contributed data to this project (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 and personal communications from H Horibe and the Shirakawa Study Group, X Li, and S Fang). 124 774 participants were included and 837 214 person-years were observed, representing average followup of 7 years (table 1). The mean values of diastolic blood pressure and cholesterol concentrations for the subgroups classified according to these variables are given in table 2, together with follow-up values
Discussion
We found strong, continuous associations between usual diastolic blood pressure and the risks of both haemorrhagic and non-haemorrhagic stroke in these populations from eastern Asia. Across a range of cholesterol concentrations, which correspond to the lower two-thirds of the distribution in most western populations, there were trends towards a positive association of cholesterol with non-haemorrhagic stroke and a negative association with haemorrhagic stroke. However, no value of usual
References (37)
- et al.
Blood pressure, stroke, and coronary heart disease—part I, prolonged differences in blood pressure: prospective observational studies corrected for the regression dilution bias
Lancet
(1990) - et al.
Subarachnoid hemorrhage, cerebral hemorrhage, and serum cholesterol concentration in men and women
Ann Epidemiol
(1993) - et al.
Serum cholesterol, other risk factors, and cardiovascular disease in a Japanese cohort
J Chron Dis
(1984) - et al.
Global pattern of cause of death and burden of disease in 1990, with projections to 2020—investing in health research and development: reportof the ad hoc committee on health research relating to future intervention options
(1996) - et al.
Comparable studies of the incidence of stroke and its pathological types: results from an international collaboration
Stroke
(1997) Cholesterol, diastolic blood pressure, and stroke: 13 000 strokes in 45 000 people in 45 prospective cohorts
Lancet
(1995)Regression models and life tables (with discussion)
J R Statist Soc B
(1972)- et al.
Cerebrovascular diseases in a fixed population of Hiroshima and Nagasaki, with special reference to relationship between type and risk factors
Stroke
(1984) - et al.
Intracerebral haemorrhage in a Japanese community, Hisayama: incidence, changing pattern during long-term follow-up, and related factors
Stroke
(1988) - et al.
Applied logistic regression
(1989)
Measurement error, instrumental variables and corrections for attenuation with applications to meta-analyses
Statist Med
A prospective study of cerebrovascular disease in Japanese rural communities, Akabane and Asahi—part 1, evaluation of risk factors in the occurrence of cerebral haemorrhage and thrombosis
Stroke
Serum cholesterol and cancer mortality in Japanese civil service workers: findings from a nested case-control study
J Epidemiol
Association of hyperinsulinemia and serum free fatty acids with serum high density lipoproteincholesterol
J Atheroscler Thromb
Relationship between serum carotenoid levels and cancer death rates in the residents living in a rural area of Hokkaido, Japan
J Epidemiol
A five year follow-up study of hypertension in 10 450 steel workers
Chin Med J
Preliminary analysis on mortality and risk factors in a Chinese population
Asian Pacific Congress on Vascular Disease Prevention
Associations between dietary pattern, clustering of risk factors, and incidence of cardiovascular diseases in Chinese populations
Asian Pacific Congress on Vascular Disease Prevention
Cited by (526)
Sex Differences in Outcomes After Spontaneous Intracerebral Hemorrhage Among Patients With Low Total Cholesterol Levels
2021, American Journal of the Medical SciencesHow should we manage hypertension and dyslipidemia to maintain cognitive function in older adults?
2023, Hypertension ResearchHypertension in China: epidemiology and treatment initiatives
2023, Nature Reviews CardiologyNational and subnational burden of stroke in Iran from 1990 to 2019
2022, Annals of Clinical and Translational Neurology
Study organisation given at end of paper