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Blood pressure and mortality during an up to 32-year follow-up
T E Strandberg1, V V Salomaa, H T Vanhanen
1Department of Medicine, University of Helsinki, Finland. timo.strandberg@hus.fi
Insights
This study on male executives found that total mortality risk remained flat until systolic blood pressure reached 131-140 mmHg. However, risk increased progressively with higher systolic blood pressure in men with other cardiovascular risk factors.
Area of Science:
- Cardiovascular epidemiology
- Public health
- Clinical research
Background:
- Elevated blood pressure is a known cardiovascular disease risk factor.
- The nature of the blood pressure-mortality association (continuous vs. threshold) is debated.
Purpose of the Study:
- To investigate the long-term relationship between baseline blood pressure and mortality.
- To determine if a threshold exists for the association between blood pressure and mortality.
Main Methods:
- Longitudinal study of 3,267 initially healthy male business executives (1964-1995).
- Baseline measurements included blood pressure and cardiovascular risk factors; no participants were on antihypertensive medication.
- Mortality follow-up via national registers, with analyses adjusted for age, BMI, smoking, and cholesterol.
Main Results:
- During follow-up (up to 32 years), 701 deaths occurred, including 234 from coronary heart disease and 49 from stroke.
- Total mortality risk was flat up to 131-140 mmHg systolic and 81-85 mmHg diastolic, then increased.
- In men with other risk factors (smoking, high cholesterol), mortality risk increased progressively with systolic blood pressure; in others, a J-shaped association was observed.
Conclusions:
- Long-term follow-up suggests a flat relationship between systolic blood pressure and mortality up to 131-140 mmHg.
- A linear relationship between systolic blood pressure and mortality is indicated in men with coexisting cardiovascular risk factors.
Background:
Elevated blood pressure is an established risk factor of cardiovascular diseases, but there is a constant debate whether the association is continuous or with a threshold.
Methods:
During the 1960s (1964 onwards), 3,267 initially healthy male business executives (born 1919-1934) participated in voluntary health check-ups with measurements of cardiovascular disease risk factors. At baseline none of the men were on antihypertensive medication. Mortality follow-up was performed using national registers up to 31 December, 1995. Follow-up total and cardiovascular mortality was related to systolic (by 10 mmHg) and diastolic (by 5 mmHg, Korotkoff's 4th phase) blood pressure at baseline. Analyses were adjusted for age, body mass index, smoking and serum cholesterol.
Results:
During an up to 32-year follow-up, there were 701 deaths, 234 (33.4%) of them due to coronary heart disease, 49 (7.0%) to stroke, 42 (6.0%) to other cardiovascular diseases and 204 (29.1%) to cancer. Total mortality curves of the whole cohort (all age groups) were flat until 131-140 mmHg (systolic) and 81-85 (diastolic) and increased thereafter. Among men who smoked and had baseline serum cholesterol > 6.5 mmol/l (n = 986), the risk of death increased progressively with systolic blood pressure, whereas among non-smoking normocholesterolaemic men (n = 504) the association was J-shaped, i.e. higher mortality at < or = 110 mmHg than between 111-150 mmHg and a more consistent rise from 151-160 mmHg. The curves were essentially similar for cardiovascular mortality. The results were supported by analyses where major cardiovascular risk factors were controlled.
Conclusion:
During a truly long-term follow-up, the relationship between systolic blood pressure and mortality was initially flat up to 131-140 mmHg although a linear relationship is suggested in men with other cardiovascular risk factors.