Blood pressure change and antihypertensive treatment in old and very old people: evidence of age, sex and cohort effects.

The epidemiology of blood pressure in very old age has not been thoroughly studied. The objective of this study was to study blood pressure changes throughout old age and changes in blood pressure and antihypertensive drug use from 1981 to 2005. The study includes 1133 blood pressure measurements from two studies carried out in Umeå, Sweden. The U70 study (1981-1990) included individuals aged 70-88 and the Umeå 85+/GERDA study (2000-2005) covered people aged 85, 90 or ≥95 years. The impact of age, sex and year of investigation on blood pressure was investigated using linear regression. Mean diastolic blood pressure (DBP) decreased by 0.35 mm Hg (P<0.001) for each year of age. An inverted U-shaped relation was found between age and systolic blood pressure (SBP), with SBP reaching its maximum at 74.5 years. Mean SBP and DBP also decreased over time (SBP by 0.44 mm Hg per year, P<0.001 and DBP by 0.34 mm Hg per year, P<0.001). The proportion of participants on antihypertensive drugs increased from 39.0% in 1981 to 69.4% in 2005. In this study of people aged ≥70 years, mean SBP and DBP decreased with higher age and later investigation year. Antihypertensive drug use increased with time, which might partly explain the observed cohort effect.