Trends in prevalence, treatment and control of hypertension in 38,825 adults over 36 years in Tromsø prospective study

Abstract

Aims/background: Serial blood pressure surveys in cohort studies can inform public health policies to control blood pressure for prevention of cardiovascular diseases.

Methods: Mean levels of systolic blood pressure (SBP) were collected in six sequential surveys, involving 38,825 individuals aged 30-79 years (51% female), between 1979 and 2015 in the Tromsø Study in Norway. Mean levels of SBP, prevalence of hypertension and use of blood pressure-lowering treatment were estimated by age, sex and calendar year of survey.

Results: Age-specific mean levels of SBP in each decade of age increased by 20-25 mmHg in men and 30-35 mmHg in women and the prevalence of hypertension increased from 25% to 75% among adults aged 30-79 years. Among successive cohorts of adults aged 40-49 years at the time of the six surveys between 1979 and 2015, the mean levels of SBP declined by about 10 mmHg and the prevalence of hypertension declined from 46% to 25% in men and from 30% to 14% in women. The proportion of individuals with hypertension who were treated increased sixfold (from 7% to 42%) between 1979 and 2015, and the proportion of adults with hypertension that were successfully controlled also increased sixfold from 10% to 60% between 1979 and 2015.

Conclusions: Although this study demonstrated a halving in the age-specific prevalence of hypertension in men and women and a sixfold increase in treatment and control of hypertension, the burden of hypertension remains high among older people in Norway.

Keywords: Hypertension; cardiovascular disease; epidemiology; heart attack; serial surveys; stroke; systolic blood pressure.

Figure 1.

Mean systolic blood pressure (a, b), proportion of hypertensives (c, d), proportion of hypertensives on treatment (e, f), and proportion of treated hypertensives achieving blood pressure control (g, h) in men (left panels, red) and women (right panels, blue) by 10-year age categories. Continuous estimates are from a linear mixed model and categorical estimates are from a GEE. All estimates are adjusted for age and sex. Hypertension is SBP/DBP ⩾ 140/90 mm Hg, treatment is proportion initiated on antihypertensives among hypertensives and control is proportion among treated hypertensives achieving SBP/DBP < 140/90 mmHg.

Figure 2.

The prevalence of hypertension (full bar) among men (a) and women (b) aged 40–49 years throughout the survey years. The bottom black bar represents the proportion of hypertensives not on treatment, the middle bar represents the proportion of treated hypertensives without blood pressure control, and the top bar represents the proportion of treated hypertensives achieving blood pressure control. Estimates are derived from GEE models adjusted for age and sex. Hypertension is SBP/DBP ⩾ 140/90 mm Hg, treatment is proportion initiated on antihypertensives among hypertensives and control is proportion among treated hypertensives achieving SBP.