Association of Blood Pressure Patterns in Young Adulthood With Cardiovascular Disease and Mortality in Middle Age

Abstract

Importance: Determining blood pressure (BP) patterns in young adulthood that are associated with cardiovascular disease (CVD) events in later life may help to identify young adults who have an increased risk for CVD.

Objective: To determine whether the long-term variability of BP across clinical visits and the rate of change in BP from young adulthood to midlife are associated with CVD and all-cause mortality by middle age, independently of mean BP during young adulthood and a single BP in midlife.

Design, setting, and participants: This prospective cohort study included a community-based sample of 3394 African American and white participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study, enrolled from March 1985 through June 1986. Patterns of systolic BP (SBP) were evaluated with measurements at year 0 (baseline) and 2, 5, 7, and 10 years after baseline. Visit-to-visit SBP variability was estimated as BP variability independent of the mean (VIM). Data were collected from March 1985 through August 2015 and analyzed from June through October 2019.

Main outcomes and measures: Cardiovascular disease and all-cause mortality experienced through August 2015 were adjudicated. The associations of each SBP pattern with CVD events and all-cause mortality were determined using Cox proportional hazards regression models.

Results: At year 10, the mean (SD) age of the 3394 participants was 35.1 (3.6) years; 1557 (45.9%) were African American; 1892 (55.7%) were women; and 103 (3.0%) were taking antihypertensive medication. During a median follow-up of 20.0 (interquartile range, 19.4-20.2) years, 162 CVD events and 181 deaths occurred. When all BP pattern measurements were entered into the same model including a single SBP measurement at the year 10 examination, the hazard ratios for CVD events for each 1-SD increase in SBP measures were 1.25 (95% CI, 0.90-1.74) for mean SBP, 1.23 (95% CI, 1.07-1.43) for VIM SBP, and 0.99 (95% CI, 0.81-1.26) for annual change of SBP. The VIM for SBP was the only BP pattern associated with all-cause mortality (hazard ratio, 1.24; 95% CI, 1.09-1.41).

Conclusions and relevance: The results of this study suggest that the assessment of visit-to-visit SBP variability may help identify young adults at increased risk for CVD and all-cause mortality later in life.

Figure.. Illustration of Systolic Blood Pressure (SBP) Patterns

Example of individual follow-up data of SBP across 5 visits (year 0 to year 10 examinations). The variability independent of the mean (VIM) of SBP was defined as the intraindividual standard deviation (SD) of SBP across examinations (M/x)^p where x is individual mean SBP across visits, M is the mean of individual mean SBP in the overall population, and p is the regression coefficient on the basis of regressing the natural logarithm of SD on the natural logarithm of the multiplication of x and M. The mean SBP was calculated as (year 0 SBP + year 2 SBP + year 5 SBP + year 7 SBP + year 10 SBP) / 5. The coefficient of variation (CV) of SBP was calculated as the SD of SBP divided by the mean SBP level. The absolute differences of SBP between successive SBP measurements are shown as Δ1 through Δ4 (blue arrows). For example, Δ1 represents the absolute difference in SBP between year 0 and year 2 measurements. The mean real variability (MRV) of SBP was calculated as (Δ1 + Δ2 + Δ3 + Δ4) / 4. The mean SBP between successive SBP measurements is shown as A1 through A4 (gray squares). Cumulative exposure to SBP was calculated as (A1 × 2 years) + (A2 × 3 years) + (A3 × 2 years) + (A4 × 3 years) and is shown by the gray shaded area, representing millimeters of mercury times years. The mean annual change in SBP from the year 0 to year 10 examinations (orange arrow) was calculated using a linear regression model. A single BP measurement in midlife was defined using the BP measurement obtained at the year 10 examination (oval).