Chronic High Stress Linked to High Blood Pressure in African Americans

Chris Calitz, M.P.P.Chris Calitz, M.P.P., Director, Center for Workplace Health

Chronic high stress over time is linked to high blood pressure in African Americans, according to an analysis published today in the Journal of the American Heart Association.

Researchers examined data on perceived stress levels and blood pressure of more than 1,800 African American adults in the Jackson Heart Study living in the Jackson, Mississippi area.

Participants’ stress levels were measured annually for up to 13 years, and their blood pressure levels were measured when they joined the study between 2000-04 and in two follow-up exams between 2005-08 and between 2009-12. None of the participants had high blood pressure or were taking antihypertensive medication when they enrolled.

Participants rated their stress levels by answering: “How much stress have you experienced over the past year?” Ratings from “none” to “moderate” were coded as low perceived stress and ratings of “a lot” or “extreme” were coded as high perceived stress. Researchers didn’t ask this question during enrollment, so they used other measures to adjust for baseline stress levels in the analysis.

During the study:
  • Almost half (48.5%) of participants developed hypertension (blood pressure ≥140/90 mm Hg or taking antihypertensive medication during either follow-up exam).
  • Compared to sustained low perceived stress, sustained high and moderate perceived stress (i.e., chronic stress) were associated with a 22% and 15% increased risk of developing hypertension, respectively.
  • The correlation between chronic high stress and hypertension was independent of depressed mood and anxiety over time. It stayed statistically significant after adjusting for participants’ hypertension risk factors, baseline stress levels and health behaviors (current smoking, alcohol use, physical activity and diet).
  • Increased risks of hypertension due to higher chronic stress was statistically significant only for women.

New learnings

The new analysis measured stress annually compared to only a single point in time. Baseline stress was not significantly different between participants who did and didn’t develop hypertension, indicating the importance of evaluating chronic stress over time rather than at a single point.

In addition, the researchers’ adjustment for factors that could overestimate the effect of stress (like depressed mood and anxiety) or influence development of high blood pressure (like certain health behaviors) suggests that higher perceived stress over time independently contributes to hypertension among African Americans.

Where do we go from here?

Chronic high stress reflects the combined effect of all possible causes of stress, such as work, finances or experiences with discrimination. The study didn’t probe deep enough to detect which specific exposures or stressors contributed more to participants’ stress levels. That’s for future research.

It would also be interesting to explore if stressful exposures have different effects on perceived stress and development of high blood pressure in different sociodemographic groups.

The complexity of some chronic stressors that disproportionately affect African Americans — such as discrimination and lower socioeconomic status — are challenging targets for intervention. But responses to those stressors may be more modifiable and strategies such as adaptive coping could help reduce the adverse cardiovascular effects of chronic stress.

Whatever the source of persistent stress, culturally relevant and effective stress management may help prevent high blood pressure in African Americans, particularly women.