Abstract P075: An Innovative Statistical Approach To Investigate The Association Of Movement Behaviors On High-sensitivity C-reactive Protein: The Jackson Heart Study

Abstract

Introduction: Over the course of 24 hours, humans engage in multiple movement behaviors including sleep, physical activity (PA), and sedentary behavior (SB) that are each associated with high-sensitivity C-reactive protein (hs-CRP). Traditional regression models do not allow for the estimation of the relative contributions of each of these behaviors on hs-CRP as they are correlated and sum to 100% of the whole day. Compositional and isotemporal substitution analyses will allow us to estimate how exchanging one behavior for another influences hs-CRP. We hypothesize an equal time amount substitution of PA (subtraction) with SB will be associated with higher hs-CRP, while substitution of sleep or SB with PA will be associated with lower hs-CRP. Methods: The Jackson Heart Study (JHS) was designed to investigate cardiovascular disease risk factors among African Americans in the Jackson, MS area. PA was self-reported via the JHS PA Cohort survey and used to calculate minutes per day of total PA. Usual nightly hours of sleep was self-reported using the JHS Sleep History Form. As compositional analysis examines proportions of a whole, SB was calculated as remaining time during the day after PA and sleep. Blood samples of hs-CRP (mg·dl -1 ) were measured by the immunoturbidimetric CRP-latex assay method. Due to being skewed right, hs-CRP was natural logarithmic transformed. Iso-temporal substitutions were calculated as a substitution in one movement behavior of 15 minutes for another while maintaining the third. Models adjusted for age, sex, smoking status, education, body mass index, and metabolic syndrome criteria. Results: The mean age of the 3,716 participants was 61.94 years (SD; 12.06) and the majority of participants were female (63.5%). The median hs-CRP concentration was 0.29 mg·dl -1 (IQR; 0.12, 0.65). Most of daily minutes was spent in SB (72.12%), followed by sleep (26.30%), and PA (1.58%). When replacing 15 minutes of PA for SB or sleep, the predicted hs-CRP was 0.03 mg·dl -1 (95% CIs; -0.00, 0.06) greater than the hs-CRP of the average participant. Substituting 15 minutes of SB for PA was associated with a predicted lowering of hs-CRP of 0.01 mg·dl -1 (-0.02, 0.00) and was similar for substituting 15 minutes of sleep for PA 0.01 mg·dl -1 (-0.03, 0.00). Substituting 15 minutes of SB for sleep, or sleep for SB was associated with no predicted change in hs-CRP (0.00 mg·dl -1 ). Conclusions: Efforts should strive to increase, or at the very least, maintain PA levels to improve measures of systemic inflammation. Future research could aim to tie the proportion of time each day spent in each movement activity to cardiovascular disease risk factors and subclinical or clinical cardiovascular disease.