Daily Sitting for Long Periods Increases the Odds for Subclinical Atheroma Plaques

Cardiorespiratory fitness decreases the odds for subclinical carotid plaques in apolipoprotein e4 homozygotes

Some studies suggest that being an apolipoprotein e4 (APOE e4) carrier increases the risk of atherosclerosis, and others suggest that cardiorespiratory fitness (CRF) could play a key role in atherosclerotic prevention. Our aim was to analyze the association of APOE e4 with carotid atherosclerosis and the association of CRF with atherosclerosis in APOE e4 carriers. A cross-sectional analysis based on a subsample of 90 participants in the Aragon Workers' Health Study was carried out. Ultrasonography was used to assess the presence of plaques in carotid territory; the submaximal Chester Step Test was used to assess CRF; and behavioral, demographic, anthropometric, and clinical data were obtained by trained personnel during annual medical examinations. APOE e4e4 participants were categorized into Low-CRF (VO_2max < 35 mL/kg/min) and High-CRF (VO_2max ≥ 35 mL/kg/min) groups. After adjusting for several confounders, compared with APOE e3e3, those participants genotyped as APOE e3e4 and APOE e4e4 showed an OR = 1.60 (95% CI 0.45, 5.71) and OR = 4.29 (95% CI 1.16, 15.91), respectively, for carotid atherosclerosis. Compared to Low-CRF APOE e4e4 carriers, the odds of carotid plaque detection were 0.09 (95% CI 0.008, 0.98) times lower among High-CRF APOE e4e4 carriers. The APOE e4e4 genotype was associated with increased carotid atherosclerosis. However, CRF is a modifiable factor that may be targeted by APOE e4e4 to decrease the elevation of atherosclerotic risk due to this genetic condition.

Prolonged sitting time links to subclinical atherosclerosis

BACKGROUND

This study investigates the association between daily sitting time and subclinical atherosclerosis by using coronary computed tomography angiography (CCTA).

METHODS

The study enrolled 203 subjects (age 57.6 ± 8.8 years) who underwent CCTA at annual medical checkups. Sitting time was categorized as < 5 hours/day (short), 5 to 9 hours/day (moderate) and ≥10 hours/d (long). We analyzed the coronary calcium score, plaque characteristics, and severity of coronary artery stenosis, including the segment involvement score (SIS) and segment stenosis score (SSS).

RESULTS

Subjects with longer sitting times tended to be male gender and have lower levels of high-density lipoprotein cholesterol (p for trend < 0.05). In addition, those with longer sitting time had higher SIS (1.2 ± 1.5 vs. 1.6 ± 2.1 vs. 2.3 ± 2.0 for short, moderate, and long sitting time, respectively) (p for trend = 0.015) and SSS (1.4 ± 2.0 vs. 1.9 ± 2.7 vs. 2.7 ± 2.6) (p for trend = 0.015), suggesting longer sitting time-correlated with the severity of coronary atherosclerosis. When considering the coronary plaque patterns, subjects with shorter sitting time (<5 hours/d) tended to have more calcified plaque and subjects with longer sitting time (≥10 hours/d) had more mixed plaque (p for trend = 0.018). After adjusting for age, gender, comorbidities, body mass index, and lipid profiles, increased sitting time was independently associated with the presence of mixed plaque, suggesting longer sitting time may be associated with higher risk of the formation of vulnerable plaque.

CONCLUSION

Longer sitting time was linked to the severity of subclinical atherosclerosis and the presence of high-risk vulnerable plaque in the general population.

Learning From Human Responses to Deconditioning Environments: Improved Understanding of the "Use It or Lose It" Principle

Physical activity, mobility or patterned mobility (i.e., exercise) is intrinsic to the functioning of Homo sapiens, and required for maintenance of health. Thus, systems such as the musculoskeletal and cardiovascular systems appear to require constant reinforcement or conditioning to maintain integrity. Loss of conditioning or development of chronic deconditioning can have multiple consequences. The study of different types of deconditioning and their prevention or reversal can offer a number of clues to the regulation of these systems and point to how deconditioning poses risk for disease development and progression. From the study of deconditioning associated with spaceflight, a condition not predicted by evolution, prolonged bedrest, protracted sedentary behavior, as well as menopause and obesity and their consequences, provide a background to better understand human heterogeneity and how physical fitness may impact the risks for chronic conditions subsequent to the deconditioning. The effectiveness of optimized physical activity and exercise protocols likely depend on the nature of the deconditioning, the sex and genetics of the individual, whether one is addressing prevention of deconditioning-associated disease or disease-associated progression, and whether it is focused on acute or chronic deconditioning associated with different forms of deconditioning. While considerable research effort has gone into preventing deconditioning, the study of the process of deconditioning and its endpoints can provide clues to the regulation of the affected systems and their contributions to human heterogeneity that have been framed by the boundary conditions of Earth during evolution and the "use it or lose it" principle of regulation. Such information regarding heterogeneity that is elaborated by the study of deconditioning environments could enhance the effectiveness of individualized interventions to prevent deconditions or rescue those who have become deconditioned.