Impact of Age on the Importance of Systolic and Diastolic Blood Pressures for Stroke Risk

The MOnica, Risk, Genetics, Archiving, and Monograph (MORGAM) Project

  1. On behalf of the MORGAM Project
  1. From the Cardiovascular Research Unit, Cardiovascular Department of Internal Medicine (J.K.K.V., J.J.) and Research Centre for Prevention and Health (J.K.K.V., A.B., A.H.A., T.J.), Glostrup University Hospital, Glostrup, Denmark; Division of Cardiology, Holbæk University Hospital, Holbæk, Denmark (H.I.); Department of Cardiovascular Epidemiology and Prevention, Cardinal Stefan Wyszynski Institute of Cardiology, Warsaw, Poland (G.B.); Cerebro and Cardiovascular Epidemiology Unit, National Centre of Epidemiology, Surveillance, and Promotion of Health, National Institute of Health, Rome, Italy (L.P., S.G., C.D.); United Kingdom Clinical Research Collaboration Centre of Excellence for Public Health Research Queen's University of Belfast, Belfast, Northern Ireland (F.K.); Clinica Medica e Istituto Auxologico Italiano, Milan, Italy (G.M.); Research Centre on Chronic Degenerative Diseases Osp. S. Gerardo, Monza, Italy (G.C.); National Institute for Health and Welfare, Helsinki, Finland (K.K.); Institute of Health Studies, Department of Health, Barcelona, Spain (S.S.); Department of Endocrinology, Odense University Hospital, Odense, Denmark (M.H.O.); Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa (M.H.O.).
  1. Correspondence to Dr Julie K. K.Vishram, Research Centre for Prevention and Health, Glostrup University Hospital, Nordre Ringvej 57, Building 84-85, 2600 Glostrup, Denmark. E-mail julievishram{at}hotmail.com

Abstract

This study investigates age-related shifts in the relative importance of systolic (SBP) and diastolic (DBP) blood pressures as predictors of stroke and whether these relations are influenced by other cardiovascular risk factors. Using 34 European cohorts from the MOnica, Risk, Genetics, Archiving, and Monograph (MORGAM) Project with baseline between 1982 and 1997, 68551 subjects aged 19 to 78 years, without cardiovascular disease and not receiving antihypertensive treatment, were included. During a mean of 13.2 years of follow-up, stroke incidence was 2.8%. Stroke risk was analyzed using hazard ratios per 10-mm Hg/5-mm Hg increase in SBP/DBP by multivariate-adjusted Cox regressions, including SBP and DBP simultaneously. Because of nonlinearity, DBP was analyzed separately for DBP ≥71 mm Hg and DBP <71 mm Hg. Stroke risk was associated positively with SBP and DBP ≥71 mm Hg (SBP/DBP ≥71 mm Hg; hazard ratios: 1.15/1.06 [95% CI: 1.12–1.18/1.03–1.09]) and negatively with DBP <71 mm Hg (0.88[0.79–0.98]). The hazard ratio for DBP decreased with age (P<0.001) and was not influenced by other cardiovascular risk factors. Taking into account the age×DBP interaction, both SBP and DBP ≥71 mm Hg were significantly associated with stroke risk until age 62 years, but in subjects older than 46 years the superiority of SBP for stroke risk exceeded that of DBP ≥71 mm Hg and remained significant until age 78 years. DBP <71 mm Hg became significant at age 50 years with an inverse relation to stroke risk. In Europeans, stroke risk should be assessed by both SBP and DBP until age 62 years with increased focus on SBP from age 47 years. From age 62 years, emphasis should be on SBP without neglecting the potential harm of very low DBP.

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  • Received July 3, 2012.
  • Revision received July 19, 2012.
  • Accepted August 20, 2012.

This Article

  1. HYPERTENSIONAHA.112.201400

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