Blood pressure in young adults from the general population in Norway strongly predicts cardiovascular events after 22 years of follow-up

Abstract Background Blood pressure (BP), elevated or hypertension, is a strong risk factor for atherosclerotic cardiovascular (CV) disease. The atherosclerotic process starts at an early age, but few contemporary studies have investigated BP in young adults and the long-term risk of CV events. Purpose To study BP in young adults from the general population and the CV risk during long-term follow-up. Methods Our prospective cohort study was initiated in the year 2000, as the "Oslo Health Study". All inhabitants born in 1969 and 1970 were invited to participate. BP was measured with a validated semi-automated device 3 times after 2 minutes rest in the seated position. The average of the last 2 measurements is further investigated. Long-term clinical follow-up was performed through linkage with mandatory national registries, 22 years after inclusion. The primary outcome was a composite of cardiovascular death, non-fatal myocardial infarction, non-fatal ischemic stroke, hospitalization for unstable angina and coronary revascularization. Cumulative incidence curves using the Aalen-Johnsen estimator were plotted to show CV events in relation to 3 baseline BP levels (level 1 120/70 mmHg, level 2 120-129/70-79 mmHg and level 3 ≥130/80 mmHg). Multivariate cox analyses were adjusted for gender, ancestry, body mass index, education ≤ 12 years, smoking status, total serum cholesterol and diabetes mellitus. Results A total of 5933 individuals were included (56% women). The median (interquartile range) age at baseline was 31 (30-31) years. Median systolic / diastolic BP was 122 (114-130) / 69 (63-75) mmHg and 109 individuals reported use of antihypertensive treatment at baseline. After 22 years of follow-up, 108 (1.8%) events occurred. There was a stepwise increase in CV events with an increasing BP level at baseline (p for trend 0.001) (Figure 1). The adjusted hazard ratio (95% confidence interval) for CV events per 1 mmHg increase in BP was 1.03 (1.01-1.04) (p-value = 0.0039) for systolic BP and 1.03 (1.01-1.05) (p-value = 0.010) for diastolic BP. Conclusion In our cohort of 30-year-old adults, recruited from the general population, both systolic and diastolic BP were strongly related to CV events during long-term follow-up. BP should be accounted for in the long-term CV risk prediction of young adults.Cumulative incidence of CV events