Blood pressure and mortality during an up to 32-year follow-up

BACKGROUNDElevated 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. METHODSDuring the 1960s (1964 onwards), 3267 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. RESULTSDuring 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 ≤ 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. CONCLUSIONDuring 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.