Influence of physical activity measurement on the association between Life's Essential 8 and incident cardiovascular disease in older women

Objective: The American Heart Association's Life's Essential 8 (LE8) metric includes self-reported physical activity as one of the metrics for assessing cardiovascular health. Self-reported physical activity is prone to misclassification, whereas accelerometer measures are less biased. We examined associations of LE8 and incident cardiovascular disease (CVD) using self-reported and accelerometer-measured physical activity. Methods: Participants in the Women's Health Initiative (WHI) Objective Physical Activity and Cardiovascular Health Study (n = 4,243; mean age = 79 +/- 7 years) with no CVD history completed the WHI physical activity questionnaire and the Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire prior to wearing a hip-worn accelerometer for up to seven days in 2012-2014. LE8 components (physical activity, diet, sleep, body mass index, smoking, blood pressure, non-HDL cholesterol, and glucose) were scored according to guidelines. Scores were created using five physical activity measures: WHI questionnaire (LE8WHI), CHAMPS (LE8CHAMPS), accelerometer-measured physical activity (LE8A), and sample quantiles of accelerometer-measured physical activity (LE8AQ) and daily steps (LE8STEPS). Hazard ratios (HR) for physician-adjudicated CVD were estimated using Cox regression. Results: 707 incident CVD events occurred over an average 7.5 years. Multivariable HRs (95 % CI) comparing women in the highest vs. lowest quartiles of LE8 scores were: LE8WHI = 0.53 (0.43-0.67), LE8CHAMPS = 0.47 (0.38-0.60), LE8A 1/4 0.44 (0.36-0.56), LE8AQ = 0.44 (0.35-0.55), and LE8STEPS = 0.45 (0.35-0.57). Conclusions: The LE8-incident CVD association varies by physical activity measurement, however all methods showed reduced risk. Device-measures of physical activity may be more accurate in the LE8, but when impractical to implement, also support use of self-reported measures.