Elevated BP before the age of 40 years associated with incident CVD events in middle age
Association of Blood Pressure Classification in Young Adults Using the 2017 American College of Cardiology/American Heart Association Blood Pressure Guideline With Cardiovascular Events Later in Life
Introduction and methods
In the 2017 ACC/AHA blood pressure (BP) guidelines, hypertension was redefined to systolic BP/diastolic BP (SBP/DBP) >130/80 mmHg [1]. As a consequence the prevalence of hypertension in young adults increased by 2- to 3-fold. For adults with stage 1 hypertension (SBP: 130-139 mmHg, DBP: 80-89 mmHg) with an estimated 10-year atherosclerotic cardiovascular disease (ASCVD) risk of at least 10%, nonpharmacological and pharmacological interventions are recommended. Young adults with stage 1 hypertension, however, generally have low 10-year ASCVD risk, and would thus not be recommended pharmacological interventions.
If stage 1 hypertension is not associated with CVD events in young adults, this implies possible overdiagnosis of hypertension, and possibly unnecessary treatment. Using data of the Coronary Artery Risk Development in Young Adults (CARDIA) Study [2], this study assessed whether adults who developed elevated BP (SBP 120-129 mmHg and DBP <80 mmHg), or hypertension before the age of 40 years have increased risk for CVD events later in life compared with normotensive counterparts. A possible effect of race and sex on this association was also assessed.
The CARDIA study enrolled over 5000 African Americans and white participants between 18 and 30 years old in 1985 and 1986. Those with CVD events before they were 40 years old were excluded. This analysis included 4851 participants with at least two BP measurements before age 40 years old (mean age at start of follow-up: 35.7 years, 55% women, 50% African-American). The mean number of visits of participants before age 40 years was 5.0 visits (SD: 1.1), over a median period of 10.7 years (IQR: 8.2-15.5). 2574 Participants were categorized as having normal BP, 445 had elevated BP, 1194 had stage 1 hypertension and 638 had stage 2 hypertension (SBP >140 mmHg, DBP >90 mmHg, or taking antihypertensive medication).
Main results
- Event rates for CVD events per 1000 person-years (PY) were highest in stage 2 hypertension group (8.04, 95%CI: 6.45-10.03), followed by the stage 1 group (3.15, 95%CI: 2.47-4.02), the elevated BP group (2.74, 95%CI: 1.78-4.20) and the normal BP group (1.37, 95%CI: 1.07-1.75).
- In a multivariable adjusted model, as compared with the normal BP group, elevated risks for CVD events were seen in those with elevated BP (HR: 1.75, 95%CI:1.01-2.77), stage 1 hypertension (HR: 1.75, 95%CI: 1.22-2.53) and stage 2 hypertension before age 40 (HR: 3.49, 95%CI: 2.42-5.05).
- During the first 10 years of follow-up, the CVD event rates per 1000 PY of the elevated BP and normal BP groups did not differ significantly. During the remainder of follow-up, the elevated BP group showed a higher event rate than the normal BP group (2.29 vs 0.73 per 1000 PY) and the HR over this period was 2.99 (95%CI: 1.63-5.48).
- All-cause mortality was higher in those with stage 2 hypertension, as compared to all other categories, and in those with stage 1 hypertension compared with the lower BP categories. Stage 2 hypertension was associated with higher all-cause mortality risk in an adjusted model, but elevated BP and stage 1 hypertension were not.
- No interaction was seen between race or sex and the relation between BP and CVD events or all-cause mortality.
Conclusion
These community-based data of white and African American participants showed an association between BP before the age of 40 years and incident CVD events and all-cause mortality by middle age. According to the BP categories defined in the 2017 ACC/AHA BP guidelines, those with elevated BP, stage 1 and stage 2 hypertension at any time before they were 40 years old, were at increased risk for CVD events, as compared with those with normal BP. The increased CVD risk in those with elevated BP compared with normal BP became apparent after 10 years. Stage 2 hypertension was also associated with a significantly higher risk of all-cause mortality.
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