Intensity of hypertensive exposure in young adulthood and subclinical atherosclerosis in middle age: Evidence from the CARDIA study.

Background: Chronically high blood pressure (HBP) is a known risk factor for cardiovascular diseases. We measured the intensity of hypertensive exposure in young adults and calculated its prognostic significance for subclinical atherosclerosis in middle age.

Methods: The Coronary Artery Risk Development in Young Adults (CARDIA) study enrolled 5,115 healthy black and white Americans who were 18-30 years old at baseline (1985-1986). The intensity of hypertensive exposure was calculated as the area under the curve (mm Hg × years) from baseline to year 15. Coronary artery calcium (CAC) was identified at years 15, 20, and 25, and intima-media thickness (IMT) was identified at year 20.

Results: At baseline, the mean age was 40.1 years; 55.1% of participants were women, and 46.5% were black. After adjustment, cumulative systolic BP (SBP) was positively associated with CAC [hazard ratio (HR) = 1.23 (1.14, 1.32)] and IMT [β = 0.022 (0.017, 0.028)]. For CAC, the C-statistic for cumulative SBP was 0.643 (0.619, 0.667); compared to baseline SBP, the net reclassification index (NRI) of cumulative SBP was 0.180 (0.115, 0.256) and the integrated discrimination improvement (IDI) was 0.023 (0.012, 0.036). For IMT, the C-statistic for cumulative SBP was 0.674 (0.643, 0.705), the NRI was 0.220 (0.138, 0.305), and the IDI was 0.008 (0.004, 0.0012).

Conclusion: Greater intensity of hypertensive exposure in early adulthood is associated with subclinical atherosclerosis in middle age and provides better prognostic value than baseline BP for early cardiovascular risk.