Circadian rhythm parameters and physical activity associated with cardiometabolic risk factors in the PREVIEW lifestyle study

Objective: The aim of this study was an assessment of post hoc associations among circadian rhythm parameters, physical activity (PA), and cardiometabolic risk factors in adults with obesity and prediabetes after 3 years of weight loss maintenance. Methods: Circadian rhythm parameters (continuous wrist-temperature measurements), PA, systolic and diastolic blood pressure (SBP, DBP), heart rate (HR), plasma high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, remnant cholesterol, triacylglycerol, and C-reactive protein (CRP) concentrations were determined in 91 free-living participants (mean [SD], age = 56.6 [10] years; BMI = 28.2 [4.0]; homeostatic model assessment of insulin resistance [HOMA-IR] = 3.2 [3.1]) and in 38 participants in sedentary respiration chamber conditions (age = 56.6 [10] years; BMI = 28.5 [4.0]; HOMA-IR = 3.3 [1.4]). Associations of circadian rhythm parameters and PA with cardiometabolic risk factors were determined using factor analyses followed by Pearson correlations. Results: Values of cardiometabolic risk factors were similar, whereas circadian rhythm parameters and PA differed significantly (p < 0.05) between conditions. In both conditions, parameters indicating a robust circadian rhythm associated inversely with CRP and positively with plasma HDL-C concentrations. In free-living conditions, PA associated inversely with SBP and HR and positively with HDL-C and robust circadian rhythm parameters. In sedentary conditions, PA associated positively with HR and inversely with robust circadian rhythm parameters. PA mediated the inverse association of parameters indicating a robust circadian rhythm with SBP in free-living conditions. Conclusions: In adults with obesity and prediabetes, parameters indicating a robust circadian rhythm were, independently of PA, associated with lower cardiometabolic risk and CRP. Only in free-living conditions, PA mediated the association of higher circadian stability with lower SBP.