Device‐Measured 24‐h Movement Behaviors and Arterial Intima‐Media Thickness in Young Adults

Physical activity, including light physical activity (LPA) and moderate-to-vigorous physical activity (MVPA), sedentary behavior (SED), and sleep, often referred to as "24-h movement behaviors", are modifiable behaviors that may be associated with arterial intima-media thickness (IMT). However, their combined associations with arterial IMT, especially aortic IMT, where cardiometabolic risk burden may be reflected at an earlier age, have not been studied before. This study examined how 24-h movement behaviors associate with aortic and carotid IMT among young adults. Participants (n = 327) were healthy young adults (mean age 26.1 years, SD 0.2) from the Special Turku Coronary Risk Factor Intervention Project (STRIP). 24-h movement behaviors were measured using a wrist-worn accelerometer for 1 week. Aortic and carotid IMT were measured with ultrasonography. Associations between 24-h movement behaviors and aortic and carotid IMT were analyzed using compositional data analysis and compositional isotemporal substitution analysis, adjusting for sex, education, smoking, and distribution of dietary fats. Descriptive model-based estimations indicated lower aortic IMT values for compositions with a higher proportion of LPA. However, theoretical time reallocations between LPA and other behaviors did not indicate significant differences in aortic IMT (e.g., 30 min from sleep to LPA, -0.005 mm [95% CI -0.020-0.010 mm], from SED to LPA, -0.006 mm [95% CI -0.018-0.006], and from MVPA to LPA, -0.008 mm [95% CI -0.038-0.021]). No associations were found for carotid IMT either. No apparent associations were observed between 24-h movement behaviors and arterial IMT among young adults.