Sedentary Patterns and Systemic Inflammation: Sex-Specific Links in Older Adults

Increased sedentary behavior is associated with neurodegeneration and worse cognition in older adults over a 7-year period despite high levels of physical activity

INTRODUCTION

Sedentary behavior may be a modifiable risk factor for Alzheimer's disease (AD). We examined how sedentary behavior relates to longitudinal brain structure and cognitive changes in older adults.

METHODS

Vanderbilt Memory and Aging Project participants (n = 404) completed actigraphy (7 days), neuropsychological assessment, and 3T brain MRI over a 7-year period. Cross-sectional and longitudinal linear regressions examined sedentary time in relation to brain structure and cognition. Models were repeated testing for effect modification by apolipoprotein E (APOE) ε4 status.

RESULTS

In cross-sectional models, greater sedentary time related to a smaller AD-neuroimaging signature (β = -0.0001, p = 0.01) and worse episodic memory (β = -0.001, p = 0.003). Associations differed by APOE-ε4 status. In longitudinal models, greater sedentary time related to faster hippocampal volume reductions (β = -0.1, p = 0.008) and declines in naming (β = -0.001, p = 0.03) and processing speed (β = -0.003, p = 0.02; β = 0.01, p = 0.01).

DISCUSSION

Results support the importance of reducing sedentary time, particularly among aging adults at genetic risk for AD.

HIGHLIGHTS

Greater sedentary behavior is related to neurodegeneration and worse cognition. Associations differed by APOE-ε4 carrier status in cross-sectional models. Sedentary behavior is an independent risk factor for Alzheimer's disease.

The effectiveness of pelvic floor muscle training on lumbar function and muscle performance in sedentary women with lower back pain: a randomized controlled trial

OBJECTIVE

This study aimed to investigate the impact of combined core and pelvic floor muscle (PFM) training on lumbar function in sedentary women with lower back pain (LBP).

METHODS

This randomized controlled study included 60 female patients divided into three groups: a control group (n = 20), a core training group (n = 20), and a combined PFM and core training group (n = 20). The participants underwent three weekly interventions over four weeks. Trunk muscle endurance, deep lumbar stabilizing muscle activity, and LBP severity were assessed before and after the intervention.

RESULTS

Following the 4-week intervention: 1. In the combined PFM and core training group, significant improvements in muscle endurance (p < 0.01) were observed, particularly in the flexor, extensor, and right abdominal muscles compared to the control group (p < 0.05). 2. In the core training group, significant increases in muscle endurance were seen in various directions (p < 0.05), with highly significant improvements in flexion and right flexion directions (p < 0.01). The flexor muscles exhibited greater endurance than the control group (p < 0.05). 3. In the control group, dorsal muscle endurance significantly decreased after four weeks (p < 0.01). 4. Pain scores after 2 h of sitting significantly decreased (p < 0.01), along with reduced LBP differences (p < 0.05). There was a decrease in pain scores (p < 0.05) and a significant reduction in LBP after 2 h of sitting (p < 0.01).

CONCLUSION

Core training, either independently or combined with PFM training, can enhance trunk muscle endurance and alleviate LBP in sedentary women with LBP. Core training alone appeared to have a more pronounced effect.

Association Between Occupational Sitting With High Sensitivity C-Reactive Protein: The Jackson Heart Study

Modifiable, behavioral risk factors like occupational sitting may contribute to inflammation, an important cardiovascular risk factor. This study evaluated the association of self-reported occupational sitting with changes in c-reactive protein (CRP) and the role of sex. We examined occupational sitting and baseline CRP levels for 2889 African American participants in the Jackson Heart Study. Four multivariable linear regression models were estimated to determine the association of occupational sitting and CRP. Analyses were conducted in 2020. The mean age was 50.8 years and 61% were female. Participants who reported occupational sitting as "often/always" had CRP levels of 4.9±6.8 mg/L, "sometimes" had levels of 4.8±8.1 mg/L, and "never/seldom" had levels of 4.3±6.8 mg/L. In the unadjusted model, "often/always" engaging in occupational sitting was significantly associated with higher levels of CRP when compared to "never/seldom" (P < .05). This differed by sex with female participants who reported "often/always" occupational sitting had CRP levels of 6.0±7.6 mg/L compared to only 5.1±6.9 mg/L for "never/seldom." Neither the overall association nor the female-specific association remained statistically significant in the adjusted models. We found an association between occupational sitting and inflammation, measured by CRP. This association varied by sex but did not remain significant after fully adjusting for covariates.

Associations of sedentary behavior and screen time with biomarkers of inflammation and insulin resistance

Sedentary behavior (SB) has been linked to risk factors of cardiometabolic disease, with inconsistent findings reported in the literature. We aimed to assess the associations of SB with multiple biomarkers of inflammation and insulin resistance in adults. Domain-specific SB, sitting time and moderate-to-vigorous physical activity (MVPA) were measured in 78 adults (mean ± SD 52.0 ± 10.8 y). Body fat percentage (BF%) was assessed using multi-frequency bioelectrical impedance. A blood draw assessed glucose, insulin, C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), leptin, and adiponectin. Adiponectin-leptin ratio (ALR), homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function (HOMA-β) were calculated. Multivariable linear regression analyses, controlling for age, sex, MVPA, and BF%, were used to assess associations. After adjustment for age, sex and MVPA, total SB (7.5 ± 2.5 h/day) was positively associated with leptin, insulin, HOMA-IR, HOMA-β (Standardized Beta (β) range 0.21-0.32) and negatively associated with ALR (β = -0.24, p < 0.05 for all). Similarly, total sitting time (7.2 ± 2.9 h/day) was associated with TNF-α (β = 0.22) and ALR (β = -0.26). These associations were attenuated to non-significance after adjustment for BF%. Leisure screen time was detrimentally associated with IL-6 (β = 0.24), leptin (β = 0.21), insulin (β = 0.37), HOMA-IR (β = 0.37), and HOMA-β (β = 0.34), independent of age, sex and MVPA (p < 0.05 for all). Only the associations with insulin (β = 0.26), HOMA-IR (β = 0.26), and HOMA-β (β = 0.23) remained significant after further controlling BF% (p < 0.05). Self-reported SB is associated with biomarkers of inflammation and insulin resistance, independent of MVPA, and in some cases BF%.

Replacing sedentary time or light physical activity with moderate physical activity is associated with a lower prevalence of back pain: a cross-sectional study using isotemporal analysis: Isotemporal substitution and LBP prevalence

BACKGROUND

Evidence shows that lack of physical activity and sedentary time are associated with higher prevalence of low back pain (LBP).

OBJECTIVE

To investigate the association between replacing sedentary time and light physical activity with a higher physical activity level with the prevalence of LBP.

METHODS

Two hundred and sixty-six individuals from a city in southeastern Brazil were recruited to this cross-sectional study. Sedentary behavior and physical activity level were evaluated using an ActiGraph GT3X tri-axial accelerometer during 7 days. The prevalence of LBP was assessed using the Nordic questionnaire. Isotemporal substitution using logistic regression analyses were performed to investigate the association between replacing an activity with another in the prevalence of LBP.

RESULTS

Replacing time spent in sedentary behavior with moderate physical activity slightly reduced the prevalence of LBP (odds ratio [OR]= 0.97; 95% CI: 0.95, 0.98). In addition, replacing time spent in light physical activity with moderate physical activity also slightly reduced the prevalence of LBP (OR= 0.97; 95% CI: 0.95, 0.98). There was no association for replacing sedentary time and light or moderate physical activity with vigorous physical activity on the prevalence of LBP.

CONCLUSIONS

The results suggest a small protective effect for LBP when replacing time in sedentary activities or light physical activity with moderate physical activity.

Novel biomarkers in the saliva of healthy young males and females in a randomized crossover study on sedentary time: An exploratory analysis

Several known biomarkers have been used to understand the physiological responses of humans to various short and long-term interventions such as exercise or dietary interventions. However, little exploratory work has been conducted to identify novel biomarkers in human saliva that could enable non-invasive physiological research to understand acute responses to interventions such as reducing sedentary time. The purpose of this study was to identify novel biomarkers in the saliva (cytokines, growth factors and vascular factors) that respond to prolonged (4 hours) and interrupted sitting (4 hours of sitting interrupted by 3 minutes of walking at 60% of maximal heart rate every 27 minutes) in young, healthy males and females. We also sought to determine whether responsive biomarkers would differ by sex. Participants (n = 24, 21.2 ± 2.2 years, 50% female) completed a prolonged sitting (PS) session and an interrupted sitting (IS) session in random order. Individual saliva samples were pooled into a male sample and a female sample to identify responsive biomarkers using a human cytokine antibody membrane array (42 targets). Several novel biomarkers were responsive in both sexes (e.g., IL-8, Angiogenin, VEGF, and EGF), in females only (e.g., TNF-α and IL-13), and in males only (e.g., IL-3, RANTES, and IL-12p40/p70). Importantly, several biomarkers appear to be responsive to the 4-hour prolonged and interrupted sitting sessions (e.g., TNF-α, IL-8, IL-3, RANTES, EGF, Angiogenin, and VEGF). This work highlights new directions for researchers aiming to investigate the effect of short-term or acute interventions on different physiological pathways using non-invasive methods. Our work clearly indicates that human saliva samples can provide a wealth of insight into physiological responses, and that a number of biomarkers can be used to understand changes induced by acute interventions such as interrupting prolonged sitting.

Leisure television watching exerts a causal effect on gastroesophageal reflux disease: evidence from a two-step mendelian randomization study

BACKGROUND

Previous studies have shown that physical activity (PA) and leisure sedentary behaviors (LSB, including leisure television watching) are linked to gastroesophageal reflux disease (GERD). However, the associations between PA/LSB and GERD remain controversial. In this study, we aimed to reveal whether these associations reflect causal relationships and reveal the potential mechanisms of these relationships using bidirectional and two-step Mendelian randomization (MR) analyses.

METHODS

We obtained genome-wide association study (GWAS) summary statistics for PA/LSB, four common risk factors (including cigarettes smoked per day, alcoholic drinks per week, triglycerides, total cholesterol) and GERD from published GWASs. A bidirectional MR analysis was performed to identify causal relationships between PA/LSB and GERD. Then, a series of sensitivity analyses were performed to verify the robustness of the results. Finally, a mediation analysis via two-step MR was conducted to investigate any effects explained by common risk factors in these relationships.

RESULTS

Genetically predicted per 1-SD increase in leisure time television watching significantly increased the risk of GERD in the bidirectional MR analysis (OR = 1.33; 95% CI: 1.14-1.56; P = 2.71 × 10- 4). Sensitivity analyses successfully verified the robustness of the causal relationship. Further mediation analysis showed that this effect was partly mediated by increasing cigarettes smoked per day, with mediated proportions of 18.37% (95% CI: 11.94-39.79%).

CONCLUSION

Our findings revealed a causal relationship between leisure television watching and an increased risk of GERD, notably, the causal effect was partially mediated by cigarettes smoked per day. These findings may inform prevention and management strategies directed toward GERD.

Sex Differences in the Association between Prolonged Sitting Time and Anxiety Prevalence among Korean Adults

Sex differences in the effect of prolonged sitting time on anxiety symptoms have not yet been explored. This study examined the sex-specific association between prolonged sitting time and anxiety prevalence in Korean adults. Community-dwelling adults aged >18 years who underwent a cross-sectional structured study survey of physical activity and mental health tests were enrolled as part of the Kangbuk Samsung Hospital Cohort Study from 2012 to 2019. The prevalence of anxiety was evaluated using the Clinically Useful Anxiety Outcome Scale (CUXOS) questionnaire. The mean daily sitting time was 7.9 ± 3.4 h in men and 6.8 ± 3.6 h in women. After adjustments for possible confounding factors, the adjusted mean CUXOS score was the highest in participants sitting for ≥10 h, followed by 5-9 h, and <5 h, in that order. In the post-hoc Bonferroni analysis, there were significant differences in the adjusted mean CUXOS scores in group comparisons. A multivariate logistic regression analysis was conducted after adjusting for potential confounding factors. A prolonged sitting time was positively associated with an increased prevalence of anxiety in both men and women, with stronger associations in women than in men. It is necessary to prevent anxiety by adjusting or reducing sitting time in adults, especially women.

Chronic inflammation: Cross linking insights from Ayurvedic Sciences, a silver lining to systems biology and personalized medicine

Precision in personalized medicine is a crucial subject that needs comprehensive discussion and scientific validation. Traditional healthcare approaches like the Ayurvedic Sciences are often contextually linked with personalized medicine. However, it is unfortunate that this knowledge concerning Ayurveda and personalized medicine is restricted to applying systems biology techniques to 'prakriti' the phenotypic expression and characterization detailed in the literature. There are other significant constructs besides prakruti that interest an Ayurvedic physician, which accounts for crafting precision in evidence-based medicinal practices. There is this influential model of Ayurvedic healthcare practice wherein the physician maps specific personalized characters in addition to prakruti to deduce the host responses to endogenous and exposome conditions. Subsequently, tailored protocols are administered that bring about holistic, personalized outcomes. The review aimed to determine the effective methods for integrating Systems Biology, Ayurvedic Sciences, and Personalized Medicine (precision medicinebased). Ayurveda adopts a holistic approach, considering multiple variables and their interconnections, while the modern reductionist approach focuses on understanding complex details of smaller parts through rigorous experimentation. Despite seeming extremes, ongoing research on lifestyle, gut health, and spiritual well-being highlights the evolving intersection between traditional Ayurvedic practices and modern science. The current focus is on developing the fundamental concept of Ayurveda Biology by incorporating Systems Biology techniques. Challenges in this integration include understanding diverse data types, bridging interdisciplinary knowledge gaps, and addressing technological limitations and ethical concerns. Overcoming these challenges will require interdisciplinary collaboration, innovative methodologies, substantial investment in technology, and cultural sensitivity to preserve Ayurveda's core principles while leveraging modern scientific advancements. The focus of discussions and debates on such collaborations should be breakthrough clinical models, such as chronic inflammation, which can be objectively related to specific stages of disease manifestations described in Ayurveda. Validating patient characteristics with systems biology approaches, particularly in shared pathologies like chronic inflammation, is crucial for bringing prediction and precision to personalized medicine.

Common and distinct risk factors that influence more severe and distressing shortness of breath profiles in oncology outpatients

BACKGROUND

Shortness of breath occurs in 10%-70% of oncology patients. Very little is known about interindividual variability in its severity and distress and associated risk factors. Using latent profile analyses (LPAs), purpose was to identify subgroups of patients with distinct severity and distress profiles for shortness of breath as single symptom dimensions. In addition, a joint LPA was done using patients' severity AND distress ratings. For each of the three LPAs, differences among the shortness of breath classes in demographic, clinical, symptom, stress, and resilience characteristics were evaluated.

METHODS

Patients completed ratings of severity and distress from shortness of breath a total of six times over two cycles of chemotherapy. All of the other measures were completed at enrollment (i.e., prior to the second or third cycle of chemotherapy). Separate LPAs were done using ratings of severity and distress, as well as a joint analysis using severity AND distress ratings. Differences among the latent classes were evaluated using parametric and nonparametric tests.

RESULTS

For severity, two classes were identified (Slight to Moderate [91.6%] and Moderate to Severe [8.4%]). For distress, two classes were identified (A Little Bit to Somewhat [83.9%] and Somewhat to Quite a Bit [16.1%]). For the joint LPA, two classes were identified (Lower Severity and Distress [79.9%] and Higher Severity and Distress [20.1%]). While distinct risk factors were associated with each of the LPAs, across the three LPAs, the common risk factors associated with membership in the worse class included: a past or current history of smoking, poorer functional status, and higher comorbidity burden. In addition, these patients had a higher symptom burden and higher levels of cancer-specific stress.

CONCLUSIONS

Clinicians can use the information provided in this study to identify high-risk patients and develop individualized interventions.

Association between dietary patterns and subjective and objective measures of physical activity among Japanese adults aged 85 years and older: a cross-sectional study

A healthy diet and regular physical activity (PA) are delineated as healthy behaviours. Their implementation is associated with better health outcomes and improved quality of life. There is less evidence of a relationship between dietary patterns (DP) and PA, especially in adults aged ≥ 85. Hence, this cross-sectional study investigates the association between DP and PA in people of this age group, using the data from The Kawasaki Aging and Well-Being Project. Brief-type self-administered diet history questionnaire was used to estimate the intake of fifty-eight types of food. After energy adjustment, principal component analysis was performed to identify DP. PA was measured objectively using an accelerometer and subjectively using a questionnaire validated for this age group. Thousand participants (median age: 86·9 years, men: 49·9 %) were included in the analysis. Three major DP (DP1 'various foods', DP2 'red meats and coffee', DP3 'bread and processed meats') were identified. DP1 'various foods' was similar to DP previously named 'healthy' or 'prudent' and showed a positive association with PA time (PAT) as measured by accelerometer (B, 6·25; 95 % CI 0·13, 12·37) and relatively shorter sedentary behaviour (SB) time. DP2 'red meats and coffee' and DP3 'bread and processed meats' were negatively associated with PAT and positively associated with SB time. This study observed the relationship between diet and PA behaviours in adults aged ≥ 85, with healthier and more food-diverse DP associated with longer PAT and relatively unhealthy DP with shorter PAT.

Inflammation, Dopaminergic Brain and Bilirubin

Dopamine is a well-known neurotransmitter due to its involvement in Parkinson's disease (PD). Dopamine is not only involved in PD but also controls multiple mental and physical activities, such as the pleasure of food, friends and loved ones, music, art, mood, cognition, motivation, fear, affective disorders, addiction, attention deficit disorder, depression, and schizophrenia. Dopaminergic neurons (DOPAn) are susceptible to stressors, and inflammation is a recognized risk for neuronal malfunctioning and cell death in major neurodegenerative diseases. Less is known for non-neurodegenerative conditions. Among the endogenous defenses, bilirubin, a heme metabolite, has been shown to possess important anti-inflammatory activity and, most importantly, to prevent DOPAn demise in an ex vivo model of PD by acting on the tumor necrosis factor-alpha (TNFα). This review summarizes the evidence linking DOPAn, inflammation (when possible, specifically TNFα), and bilirubin as an anti-inflammatory in order to understand what is known, the gaps that need filling, and the hypotheses of anti-inflammatory strategies to preserve dopamine homeostasis with bilirubin included.

Resistance training rejuvenates aging skin by reducing circulating inflammatory factors and enhancing dermal extracellular matrices

Aerobic training (AT) is suggested to be an effective anti-aging strategy for skin aging. However, the respective effects of resistance training (RT) have not been studied. Therefore, we compared the effects of AT and RT on skin aging in a 16-week intervention in 61 healthy sedentary middle-aged Japanese women. Data from 56 women were available for analysis. Both interventions significantly improved skin elasticity and upper dermal structure, and RT also improved dermal thickness. After the training intervention, expression of dermal extracellular matrix-related genes was increased in normal human primary dermal fibroblasts. AT and RT had different effects on circulating levels of factors, such as cytokines, hormones in serum, and metabolites, and RT increased dermal biglycan (BGN). To our knowledge, this is the first report to show different effects of AT and RT on skin aging and identify the key factors involved in RT-induced skin rejuvenation.

Dose-response effects of periodic physical activity breaks on the chronic inflammatory risk associated with sedentary behavior in high- and upper-middle income countries: A systematic review and meta-analysis

BACKGROUND AND AIMS

Though moderate-vigorous physical activity (MVPA) is speculated to mitigate the inflammatory risk associated with sedentary behavior, only a fraction of the global population meets the recommended weekly dose of MVPA. More individuals indulge in bouted and sporadic light-intensity physical activity (LIPA) that occurs throughout the typical day. However, the anti-inflammatory effects of LIPA or MVPA breaks during prolonged sitting remains unclear.

METHODS

A systematic search was done on six peer-reviewed databases through January 27th, 2023. Two authors independently screened the citations for eligibility, and risk of bias and performed a meta-analysis.

RESULTS

The included studies originated from high and upper - middle income countries. Observational studies of SB interruptions with LIPA showed favourable effects on inflammatory mediators such as higher levels of adiponectin (odds ratio, OR = +0.14; p = 0.02). However, these findings are not supported by the experimental studies. Experimental studies reported non-significant increase in cytokines including IL-1β (standardised mean difference, SMD = 0.11 pg/ml; p = 0.29) and IL-6 (SMD = 0.19 pg/ml; p = 0.46) after interrupting sitting with LIPA breaks. But these LIPA breaks were found to reduce C-reactive protein (SMD = - 0.50 mg/dl; p = 0.85) and IL-8 levels (SMD = -0.08 pg/ml; p = 0.34) but did not reach statistical significance.

CONCLUSION

Interrupting prolonged sitting time with LIPA breaks shows promise for preventing the inflammatory effects associated with prolonged bouts of daily sitting, though the evidence remains in infancy and limited to high- and upper-middle income countries.

Association between sedentary behavior and chronic kidney disease in Korean adults

BACKGROUND

Chronic kidney disease (CKD) is a significant health care burden, with a worldwide prevalence of approximately 11%. The general population spends over 50% of the awake time sedentary activities. However, to the best of our knowledge, no study has evaluated the association between sedentary time and CKD, with a focus on both kidney damage and kidney function, in the South Korean population. Accordingly, the present study aimed to address this gap in the knowledge.

METHOD

We used data from the 8^th Korea National Health and Nutrition Examination Survey. The analysis included 9,534 participants, especially excluded those who had been diagnosed with kidney disease or who were currently undergoing treatment. Sedentary behavior was self-reported by the participants. An estimated glomerular filtration rate (eGFR) and/or albuminuria were used as measures for detection of CKD according to the guidelines of the Kidney Disease Improving Global Outcomes. We analyzed the data using multiple logistic regression.

RESULTS

Among the women, the risk of CKD was significantly greater among those who sat for ≥ 12 h/d relative to those who sat for < 6 h/d, after adjusting for physical activity and other covariates (odds ratio [OR]: 1.45, 95% confidence interval [CI]: 1.01-2.06). Similarly, among those who sat over 12 h/d, those who engaged in low levels of physical activity had a higher risk of CKD than those who engaged in high levels of activity (OR: 1.65, 95% CI: 1.04-2.61). No statistically significant results were found for men.

CONCLUSION

Excessive sedentary behavior was associated with an increased risk of CKD, especially albuminuria, regardless of the level of physical activity, only in women. These findings emphasize the importance of avoiding excessive sitting for a long time and increasing overall physical activity levels.

Device-based physical activity and late-life depressive symptoms: An analysis of influential factors using share data

BACKGROUND

Regular physical activity is effective for preventing and managing depression; however, only a few studies have assessed physical activity using device-based measures. We aimed to examine the association between device-based total physical activity and late-life depressive symptoms and explore which factors may explain this relationship.

METHODS

Data from 10 European countries who participated in wave 8 of the Survey of Health, Ageing and Retirement in Europe (SHARE) were analyzed. Triaxial accelerometers (Axivity AX3; Axivity, Newcastle UK) were used to assess total physical activity. Depressive symptoms were assessed through the EURO-D scale. Possion regression models and mediation analysis were performed.

RESULTS

The final sample included 785 older adults (70 participants had missing data in one or more variables and were excluded from the analysis) [mean (SD): age 68.6 (8.8) years; 59.2 % female]. After adjusting for several confounders, a 10 % increase in the mean acceleration was associated with lower depressive symptoms (B = -0.0228; 95%CI = -0.0395, -0.0061). This association was partly explained by limitations in activities of daily living and quality of life.

LIMITATIONS

Cross-sectional design, convenience sample, bi-directionality, lack of cutoff points for classification of the Axivity AX3 placed in the thigh, into intensities.

CONCLUSIONS

Higher device-based total physical activity was linked with lower depressive symptoms in older European adults. Future studies employing device-based measures that allow to better capture important physical activity dimensions (i.e., intensity) will better inform about dose-response relationships.

A Sedentary and Unhealthy Lifestyle Fuels Chronic Disease Progression by Changing Interstitial Cell Behaviour: A Network Analysis

Managing chronic diseases, such as heart disease, stroke, diabetes, chronic lung disease and Alzheimer’s disease, account for a large proportion of health care spending, yet they remain in the top causes of premature mortality and are preventable. It is currently accepted that an unhealthy lifestyle fosters a state of chronic low-grade inflammation that is linked to chronic disease progression. Although this is known to be related to inflammatory cytokines, how an unhealthy lifestyle causes cytokine release and how that in turn leads to chronic disease progression are not well known. This article presents a theory that an unhealthy lifestyle fosters chronic disease by changing interstitial cell behavior and is supported by a six-level hierarchical network analysis. The top three networks include the macroenvironment, social and cultural factors, and lifestyle itself. The fourth network includes the immune, autonomic and neuroendocrine systems and how they interact with lifestyle factors and with each other. The fifth network identifies the effects these systems have on the microenvironment and two types of interstitial cells: macrophages and fibroblasts. Depending on their behaviour, these cells can either help maintain and restore normal function or foster chronic disease progression. When macrophages and fibroblasts dysregulate, it leads to chronic low-grade inflammation, fibrosis, and eventually damage to parenchymal (organ-specific) cells. The sixth network considers how macrophages change phenotype. Thus, a pathway is identified through this hierarchical network to reveal how external factors and lifestyle affect interstitial cell behaviour. This theory can be tested and it needs to be tested because, if correct, it has profound implications. Not only does this theory explain how chronic low-grade inflammation causes chronic disease progression, it also provides insight into salutogenesis, or the process by which health is maintained and restored. Understanding low-grade inflammation as a stalled healing process offers a new strategy for chronic disease management. Rather than treating each chronic disease separately by a focus on parenchymal pathology, a salutogenic strategy of optimizing interstitial health could prevent and mitigate multiple chronic diseases simultaneously.

Physical Activity Rewires the Human Brain against Neurodegeneration

Physical activity may offset cognitive decline and dementia, but the molecular mechanisms by which it promotes neuroprotection remain elusive. In the absence of disease-modifying therapies, understanding the molecular effects of physical activity in the brain may be useful for identifying novel targets for disease management. Here we employed several bioinformatic methods to dissect the molecular underpinnings of physical activity in brain health. Network analysis identified 'switch genes' associated with drastic hippocampal transcriptional changes in aged cognitively intact individuals. Switch genes are key genes associated with dramatic transcriptional changes and thus may play a fundamental role in disease pathogenesis. Switch genes are associated with protein processing pathways and the metabolic control of glucose, lipids, and fatty acids. Correlation analysis showed that transcriptional patterns associated with physical activity significantly overlapped and negatively correlated with those of neurodegenerative diseases. Functional analysis revealed that physical activity might confer neuroprotection in Alzheimer's (AD), Parkinson's (PD), and Huntington's (HD) diseases via the upregulation of synaptic signaling pathways. In contrast, in frontotemporal dementia (FTD) its effects are mediated by restoring mitochondrial function and energy precursors. Additionally, physical activity is associated with the downregulation of genes involved in inflammation in AD, neurogenesis in FTD, regulation of growth and transcriptional repression in PD, and glial cell differentiation in HD. Collectively, these findings suggest that physical activity directs transcriptional changes in the brain through different pathways across the broad spectrum of neurodegenerative diseases. These results provide new evidence on the unique and shared mechanisms between physical activity and neurodegenerative diseases.

Consumption of Vegetables Is Associated with Systemic Inflammation in Older Adults

It is hypothesized that healthy diets rich in fruits and vegetables (FV) can modulate the inflammatory status in older adults. However, to determine the actual impact of FV on inflammatory status, adiposity level and objectively assessed physical activity (PA) behaviors need to be considered. The aim of the present study was to explore associations between FV intake and biomarkers of systemic inflammation in older adults. Based on a sample of 233 older adults (65−70 years old), the following inflammatory biomarkers were assessed: C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), IL-10, IL-18, and monocyte chemoattractant protein-1 (MCP-1). FV intake was assessed by self-report, and PA behaviors encompassing time spent sedentary and in moderate-to-vigorous PA (MVPA) were determined using accelerometers. Associations between FV intake and inflammatory biomarkers were analyzed using stepwise linear regression models while adjusting for several covariates, including health-related food groups, adherence to the MVPA guidelines, total sedentary time, and waist circumference. While no significant associations were observed for the total FV intake, the vegetable intake was inversely associated with levels of IL6 (β = −0.15; p < 0.05). In contrast, fruit intake was not associated with any inflammatory biomarker. In conclusion, our findings indicate beneficial associations between vegetable intake and levels of a pro-inflammatory biomarker in older adults, which strengthens public health efforts to promote vegetable-rich diets in older adults to mitigate age-related systemic inflammation.

Associations between objectively measured physical activity, sedentary time, and cardiorespiratory fitness with inflammatory and oxidative stress markers and heart rate variability

Background

To assess the associations between physical activity (PA) and sedentary time (SEDT) with inflammatory and oxidative stress markers, heart rate variability (HRV) and post-exercise recovery (HRR) controlling for cardiorespiratory fitness (CRF) and potential confounders.

Design and methods

The following data was collected from 44 participants during 2019 (age = 49.5 ± 6.4 years, 66% women): Plasma levels of C-reactive protein (CRP) and cytokines (IL-1β, INF-γ, TNF-α, MCP-1, IL-6, IL-8, IL-10, IL-18, IL-23); catalase (CAT) and glutathione peroxidase (GPX) activities; resting heart (HR) rate for HRV analysis, anthropometric measures, a submaximal cycling test to evaluate CRF with active recovery to assess and HRR (absolute and ΔHR), and 7-day accelerometry.

Results

Women spent significantly more SEDT (p = 0.035), had higher inflammatory markers (IL-6 and TNF) and lower HRV indices [SDNN, LF/HF, SD2 (p > 0.05)]. Significant associations were found between SEDT and markers of inflammation [CRP, B = 0.006, p = 0.001; MCP-1, B = 0.003, p = 0.038]. HRV indices were significantly associated with inflammatory/oxidative stress markers [IL-10 (p = 0.04), GPX (p = 0.014), ln-IL 23 (p = 0.036), CAT (p = 0.026)] while HRR was positively associated with light PA [Δ3 (B = 0.051, p = 0.043), Δ4 (B = 0.062, p = 0.021)] and inversely related to catalase [Δ3 (B = -54.7, p = 0.042), Δ4 (B = -54.1, p = 0.021] and CRP [Δ5 (B = -19.8, p = 0.033)]. Higher CRF showed lower values for TNF-α (p = 0.02) and IL-10 (p = 0.003) and better HRV/HRR indices [RMSSD, PNS, SampEn, SD1 (p < 0.05)].

Conclusions

SEDT had a higher impact on inflammation and autonomic balance, independently of PA levels with differences by sex and CRF. PA appears to be more important for a better HRR. Lower HRV and HRR could be indicative of inflammatory status.

Benefits of Fruit and Vegetable Consumption on Prevalence of Metabolic Syndrome Are Independent of Physical Activity Behaviors in Older Adults

Although consumption of fruits and vegetables (FV) is suggested to reduce metabolic risk, there is a paucity of studies taking advantage of objectively assessed physical activity (PA) behaviors when exploring links between FV intake and metabolic syndrome (MetS) in older adults. The aim of the present study was to determine the relationship between FV intake and MetS prevalence in a population of older community-dwelling adults, while considering time spent being sedentary and health-enhancing PA. Prevalence of MetS was determined in a population of 93 men and 152 women (age: 65–70 years). FV intake was determined by self-report and PA behaviors (time spent in moderate-to-vigorous PA (MVPA) and in sedentary) were assessed by accelerometry. Likelihood of having MetS by FV intake was determined using logistic regression with stepwise backward elimination including age, sex, educational level, total energy intake, adherence to MVPA guideline and total sedentary time as covariates. A main finding was that lower FV intakes were significantly related to higher prevalence of MetS (odds ratio [OR]: 1.23; 95% confidence interval [CI]: 1.03–1.47) after considering potential influences by covariates. Additionally, we found that lower intake of vegetables but not fruits was significantly related to higher prevalence of MetS (OR: 1.47; 95%CI: 1.04–2.07). In conclusion, lower intakes of FV in general, and of vegetables in particular, significantly increased likelihood of MetS, regardless of time spent sedentary and adherence to the MVPA guideline. From a public health perspective, our findings emphasize adequate intakes of FV as an independent contributor to metabolic health status in older adults.

Association of accelerometer-measured physical activity with kidney function in a Japanese population: the DOSANCO Health Study

BACKGROUND

Sedentary behavior and decreased physical activity are associated with reduced kidney function, yet most evidence is based on self-reported physical activity. This study investigated the association between accelerometer-based physical activity level and kidney function in a general Japanese population.

METHODS

A cross-sectional study was conducted in 440 community-dwelling Japanese participants, aged 35-79 years. Time (min/d) was assessed for the following types of physical activity: sedentary behavior, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA). Kidney function was assessed using estimated glomerular filtration rate (eGFR). A linear regression model was employed to calculate the β coefficient of eGFR for a 60-min/d increase in sedentary behavior and LPA and a 10-min/d increase in MVPA. A logistic regression model was used to calculate the odds ratio for low eGFR (< 60 versus ≥60 mL/min/1.73m²) for a 60-min/d or 10-min/d increase in each physical activity type.

RESULTS

MVPA time and eGFR were positively associated in both men and women, after adjusting for age, body mass index, and other clinical characteristics (Men: β, 0.91; P = 0.021; Women: β, 0.70; P = 0.034). In women, sedentary behavior and eGFR were inversely associated after adjusting for the same factors (β, - 1.06; P = 0.048). The odds ratio (95% confidence interval) for low eGFR associated with a 60-min increase in sedentary behavior was 1.65 (1.07-2.55) after adjusting for the same factors in women.

CONCLUSION

Longer sedentary behavior and shorter MVPA time were associated with lower kidney function in the Japanese population.

Associations between Circulating Inflammatory Biomarkers and Indicators of Muscle Health in Older Men and Women

Systemic inflammation is believed to contribute to declining muscle health during aging. The present study aims to examine associations between indicators of muscle health and pro- and anti-inflammatory biomarkers in older men and women, while also considering the impacts of physical activity and protein intake. An assessment of skeletal muscle index (SMI) by bioelectrical impedance analysis, handgrip strength, and 5-sit-to-stand time, using standardized procedures, was conducted in a population of older men (n = 90) and women (n = 148) aged 65–70 years. The inflammatory biomarkers C-reactive protein (CRP), fibrinogen, interleukin (IL)-6, IL-10, IL-18, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1α were assessed in blood samples. Data were analyzed and stratified according to biological sex using multiple linear regression models. In older women, SMI was inversely associated with the pro-inflammatory markers CRP (β = −0.372; p < 0.05), fibrinogen (β = −0.376; p < 0.05), and IL-6 (β = −0.369; p < 0.05). Importantly, these associations were independent of abdominal adiposity (waist circumference), protein intake, physical activity level, as well as any adherence to muscle strengthening guidelines (≥2 sessions/week). In contrast, no corresponding associations were observed in men. In conclusion, our findings indicate the detrimental influence of a pro-inflammatory environment on muscle health regardless of important lifestyle-related factors in older women. However, the lack of such associations in older men highlights the importance of considering biological sex when examining the complex interaction between the systemic inflammatory environment and muscle health.