Introduction and Hypothesis: Chronic stress has been associated with incident hypertension but evidence is mixed, particularly in African Americans. We tested the hypothesis that higher cumulative exposure to stress would be associated with increased risk of developing hypertension in the Jackson Heart Study (JHS), a prospective study of cardiovascular disease in African Americans.
Methods: Analyses included 1,442 JHS participants free of hypertension at baseline (2000-2004) who completed at least 3 annual follow-up telephone interviews. Incident hypertension was defined as systolic blood pressure (SBP) ≥140 mm Hg or diastolic BP (DBP) ≥90 mm Hg or use of antihypertensive medications at Exam 2 (2005-2008) or Exam 3 (2009-2013). A single-item measure of stress (“How much stress have you experienced over the past year?”) was completed during annual interviews, and the percentage of assessments in each measurement interval (i.e., between Exams 1 and 2, between Exams 2 and 3) in which high stress was reported was categorized as No Chronic Stress (0%), Low Chronic Stress (1-33.3%) or High Chronic Stress (>33.3%). Chronic stress exposure in each interval was used to predict incident hypertension at the following exam among participants free of hypertension at the start of the interval using repeated measures Poisson regression models with progressive adjustment for age, sex, years between exams and other relevant risk factors (education, marital status, parental history of hypertension, baseline SBP and DBP, body mass index, diabetes, chronic kidney disease).
Results: The 1,442 participants in this analysis contributed data to 1,987 measurement intervals. The mean age was 49±0.26 years and 41% were male. During follow-up (median, 8 years), 44.0% of participants developed hypertension. The percentage of intervals with No, Low and High chronic stress was 62.3%, 9.2% and 28.6%, respectively. Multivariable-adjusted risk ratios (95% confidence interval) for incident hypertension associated with Low (vs. No) and High (vs. No) chronic stress were 1.11 (0.90-1.37) and 1.21 (1.06-1.38), respectively (P trend=0.005). This association remained statistically significant after further adjustment for baseline stress (P trend=0.014) and potential behavioral mediators (smoking, alcohol use, physical activity, diet; P trend=0.03). In stratified analyses, the association was present in women (P trend=0.002), younger participants (<50 years old; P trend=0.007) and those with normal BP at baseline (P trend=0.001).
Conclusion: We found that African Americans reporting higher chronic stress over time are at increased risk of developing hypertension, independent of baseline stress levels and cardiovascular and behavioral risk factors. Future studies should evaluate the use of stress management interventions to support primary prevention of hypertension in this high risk population.