Cardiovascular
Cumulative exposure to risk factors and subsequent cardiovascular disease events: The Jackson Heart Study Rishi Parikh* Rishi Parikh Paul Muntner Shakia Hardy Mario Sims Yuan-I Min Kendra Sims Alexis Reeves Yongmei Li Michelle Odden
Background: Cumulative exposure to risk factor levels may capture additional future CVD risk independent of a single measure later in life. We examined the association between cumulative exposure to systolic blood pressure (SBP), low-density lipoprotein cholesterol (LDL-C), and fasting plasma glucose (FPG) with CVD events among African-American participants in the Jackson Heart Study (JHS).
Methods: We included all JHS participants with SBP, LDL-C, and FPG measurements at Exams 1 (2000-2004) and 3 (2009-2013) who were alive at 8 years of follow-up after Exam 1. We calculated 8-year cumulative exposures as the area under the trajectory of each risk factor using all available measurements from Exams 1, 2, and 3. Adjudicated coronary heart disease (CHD), stroke, and heart failure (HF) events after 8 years were evaluated as outcomes in separate models. We used conditional Cox regression models for recurrent events, with 8-year cumulative exposures of risk factors, values of the risk factor at 8 years after Exam 1, and covariates at Exam 1 as independent variables. Models were conducted separately for each risk factor, and exposures were standardized for comparability.
Results: Among 3,188 eligible JHS participants, mean age was 54 years, and 64% were women. Over a median follow-up of 6.2 years, there were 88 CHD, 78 stroke, and 519 HF events. Cumulative exposures to SBP and LDL-C were associated with more CHD events after adjustment for covariates and the 8-year value, with cumulative exposure to LDL-C having the strongest association [adjusted hazard ratios (aHR) per SD: 1.79 (95% CI: 1.13, 2.86)] (Table). Cumulative exposure to SBP and FPG were associated with HF events after adjustment [aHR: 1.10 (95% CI: 1.02, 1.18) and 1.08 (95% CI: 1.00, 1.15), respectively]. Estimates of cumulative and 8-year values of all 3 risk factors were in the harmful direction for stroke events, but only the 8-year values were robustly associated with stroke.
Conclusions: Cumulative exposure to risk factors provides additional information on CVD risk compared with single measurements later in life. CVD risk stratification methods in African American adults should consider long-term risk factor levels when assessing CVD risk.
