Joint Association of Moderate-to-vigorous Intensity Physical Activity and Sedentary Behavior With Incident Functional Limitation: Data From the Osteoarthritis Initiative

Physical activity and the osteoarthritis of the knee: A Mendelian randomization study

Previous studies have reported an association between physical activity and the occurrence and progression of knee osteoarthritis (KOA). However, the existing evidence remains limited and of low-quality. This study aimed to examine the causal relationship between different levels of physical activity and KOA. Instrumental variables, represented by single nucleotide polymorphisms (SNPs), were utilized to capture sedentary behavior, appropriate physical exercise, and excessive physical activity. Aggregated statistics from the UK Biobank genome-wide association study dataset were used to assess the impact of these SNPs on KOA. Causality was estimated using inverse variance weighting (IVW), MR Egger, simple model, weighted median, and weighted model approaches. The stability of the results was assessed through heterogeneity and sensitivity analyses. Mendelian randomization (MR) analysis revealed a strong association between sedentary behavior and KOA, with an odds ratio (OR) of 2.096 (95% CI: 1.506-2.917) and a P value of 1.14 × 10-5. Appropriate physical exercise behavior exhibited a strong negative association with KOA, with an OR of 0.147 (95% CI: 0.037-0.582) and a P value of 0.006. Conversely, excessive physical activity behavior showed a significant positive association with KOA, with an OR of 2.162 (95% CI: 1.327-3.521) and a P value of .002. Our findings indicate that sedentary behavior and excessive physical activity are identified as risk factors for KOA, whereas engaging in appropriate physical exercise emerges as a protective factor against the development of KOA.

Maximal daily stepping cadence partially explains functional capacity of individuals with end-stage knee osteoarthritis

BACKGROUND

Individuals with end-stage knee osteoarthritis (OA) walk at a lower intensity (ie, slower step cadence) contributing to worse physical function. Previous literature reports daily step counts and sedentary time, with little information regarding stepping bouts or cadence. Determining relationships between daily higher stepping cadence duration and clinical outcomes can move the field toward optimal daily stepping prescription.

OBJECTIVE

To quantify daily physical activity patterns of individuals with end-stage knee OA and determine the contribution of high stepping cadence to explain functional capacity variability.

DESIGN

Cross-sectional analysis.

SETTING

Veterans Administration medical center.

PARTICIPANTS

U.S. military veterans (n = 104; age: 67.1 years [7.2]; mean [SD]; male [89.3%]) with end-stage knee OA were enrolled.

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE

Functional capacity (6-Minute Walk Test [6MWT]). Physical activity (activPAL wearable sensor; cadence and time sitting, standing, and stepping), pain (Western Ontario and McMaster Universities Osteoarthritis Index-pain subscale) sociodemographic variables, and comorbidities (body mass index and Functional Comorbidity Index) are the main explanatory variables.

RESULTS

Participants' wake time was mainly sitting (11.0 h/day) in ≥60-minute bouts (29.7% ± 12.7 of sitting time). Standing (3.4 hours/day) and stepping (1.4 h/day) primarily occurred in 0-5 minute bouts (standing: 87.7% ± 14.4 of standing time, stepping: 98.7% ± 12.7 of stepping time) and stepping cadence was predominantly incidental (1-19 spm; 52.9% ± 9.6 of total stepping time). Backward elimination model results indicated shorter medium-to-brisk cadence bout duration, older age, and higher pain significantly explained shorter 6MWT distance (AdjR2=0.24, p < .01).

CONCLUSIONS

Individuals with knee OA spend most of their waking hours sitting, while standing and stepping occurs in short bouts at very low stepping cadence. Decreased time in high stepping cadence is associated with lower functional capacity. Future studies should explore if increasing the daily time spent in higher step cadence can improve functional capacity in this population.

Causal effect of physical activity and sedentary behaviors on the risk of osteoarthritis: a univariate and multivariate Mendelian randomization study

There is still a lot of ambiguity about the link between physical activity (PA), sedentary behaviors (SBs) and osteoarthritis (OA). This study aimed to investigate the causal relationship of PA/SBs on the risk of OA. A univariate and multivariate Mendelian randomization (MR) analysis was conducted to investigate the causal effect of five PA phenotypes and three SB phenotypes on overall OA, knee OA, hip OA, total hip arthroplasty, and total knee arthroplasty (TKA). MR methods used were inverse-variance weighting, MR-Egger regressions, and weighted median. Sensitivity analysis examined horizontal pleiotropy and heterogeneity, and confirmed the reliability of the results. After false discovery rate, light do-it-yourself (DIY) activities decreased the risk for overall OA (OR: 0.32, 95% CI 0.16-0.65), and knee OA (OR: 0.26, 95% CI 0.12-0.51). Resulting in a decreased risk of walking for pleasure on overall OA (OR: 0.87, 95% CI 0.70-1.04) and knee OA (OR: 0.14, 95% CI 0.06-0.32) was also observed. Television viewing, however, significantly increased the risk of OA, knee OA, hip OA, and TKA. MVMR findings revealed independent causal impacts of walking for pleasure and watching television on overall and knee OA, taking into account BMI, smoking, and education. This study suggested that light DIY and walking for pleasure were beneficial for preventing OA, and the risk of OA and TKA increased with prolonged television watching.

The association between basal metabolic rate and osteoarthritis: a Mendelian randomization study

BACKGROUND

The role of the basal metabolic rate (BMR) in osteoarthritis (OA) remains unclear, as previous retrospective studies have produced inconsistent results. Therefore, we performed a Mendelian randomization (MR) study to systematically investigate the causal relationship between the BMR and OA.

METHODS

Single-nucleotide polymorphism (SNP) data related to BMR and OA were collected in a genome-wide association study. Using OA as the outcome variable and BMR as the exposure factor, SNPs with strong correlation with the BMR as the tool variable were screened. The correlation between the BMR and OA risk was evaluated using the inverse-variance weighted method, and heterogeneity and pleiotropy were evaluated using a sensitivity analysis.

RESULTS

There was a potential causal relationship between the BMR and OA risk (odds ratio [OR], 1.014; 95% confidence interval [CI], 1.008-1.020; P = 2.29e - 6). A causal relationship was also revealed between the BMR and knee OA (OR, 1.876; 95% CI, 1.677-2.098; P = 2.98e - 28) and hip OA (OR, 1.475; 95% CI, 1.290-1.686; P = 1.26e - 8). Sensitivity analysis confirmed the robustness of these results.

CONCLUSION

Here, we identified a latent causal relationship between the BMR and the risk of OA. These results suggest that the risk of OA in the hip or knee joint may be reduced by controlling the BMR.

Assessment of causal effects of physical activity on the risk of osteoarthritis: a two-sample Mendelian randomization study

BACKGROUND

Growing evidence supports an association between physical activity (PA) and the risk of osteoarthritis (OA), but this may be influenced by confounding and reverse causality. Therefore, we performed a two-sample Mendelian randomization (MR) analysis to reveal the causal relationship between PA and OA.

METHODS

MR was performed to explore the causation of PA and OA with genetic variants as instrumental variables. The genetic variants were derived from the summary statistics of a large genome-wide association study meta-analysis based on the European population (n = 661,399), including self-reported leisure screen time (LST) and moderate-to-vigorous physical activity (MVPA), and Arthritis Research UK Osteoarthritis Genetics Consortium cohorts (417,596, 393,873 and 403,124 for overall, hip and knee OA, respectively). The major MR analysis used in this work was the inverse variance weighted (IVW) approach, and sensitivity, pleiotropy, and heterogeneity studies were performed to evaluate the validity of the findings.

RESULTS

IVW estimates indicated that LST had a risk effect on overall OA (odds ratio (OR) = 1.309, 95% confidence interval (CI): 1.198-1.430, P = 2.330 × 10-9), hip OA (OR = 1.132, 95% CI: 1.009-1.269, P = 0.034) and knee OA (OR = 1.435. 95% CI: 1.286-1.602, P = 1.225 × 10-10). In contrast, no causal relationship was found between MVPA and OA (overall OA: OR = 0.895, 95% CI: 0.664-1.205, P = 0.465; hip OA: OR = 1.189, 95% CI: 0.792-1.786, P = 0.404; knee OA: OR = 0.707, 95% CI: 0.490 -1.021, P = 0.064). In addition, we observed significant heterogeneity in instrumental variables, but no horizontal pleiotropy was detected.

CONCLUSIONS

Recent findings demonstrated a protective impact of reducing LST on OA, independent of MVPA. This provides valuable insights into the role of physical activity in OA and offers lifestyle recommendations, such as reducing recreational sedentary behaviors and promoting appropriate exercise, for individuals at risk of OA.

Physical Activity, Sedentary Behavior, and Osteoarthritis: A Two-Sample Mendelian Randomization Analysis

Background

Sedentary behavior and physical activity are still ambiguous in their effects on osteoarthritis. We aimed to evaluate the effects of physical activity and sedentary behavior on osteoarthritis to provide a reference for the prevention of osteoarthritis.

Methods

This study was conducted in Changchun, China in 2022. We used two-sample Mendelian randomization with the SNP as an instrumental variable to investigate the effect of physical activity and sedentary behavior on osteoarthritis. In addition, a two-step Mendelian randomization method was used to test whether mediating factors (BMI, smoking, Apolipoprotein B) were involved in mediating the effects of exposure factors on osteoarthritis.

Results

TV watching was causally related to knee osteoarthritis and spine osteoarthritis, and they were positively correlated (knee osteoarthritis: OR=1.162,95 %CI: 1.027-1.315, P=0.017; spine osteoarthritis: OR=1.208,95 %CI: 1.033-1.413, P=0.018). BMI played a mediating role in the process of TV watching with knee osteoarthritis and spine osteoarthritis. ((The proportion of BMI mediating effect: knee osteoarthritis: 47.1% (95% CI: 36.7%~63.2%); spine osteoarthritis: 29.5% (95% CI: 19.3%~40.8%)). The proportion of Smoking mediating effect in the process of TV watching with spine osteoarthritis was 16.1% (95% CI: 3.7% ~ 31.6%).

Conclusion

TV watching is a potential risk factor for osteoarthritis and plays a role through modifiable factors such as BMI and smoking, therefore, interventions on these factors have the potential to reduce the burden of osteoarthritis caused by longer TV watching times.

Causal association of leisure sedentary behavior with arthritis: A Mendelian randomization analysis

OBJECTIVES

This study aimed at exploring the potential causal effects of leisure sedentary behavior (LSB) on common types of arthritis.

METHOD

Two-sample Mendelian randomization (MR), including both univariable MR (UVMR) and multivariable MR (MVMR) analysis, was performed to explore the effects of LSB on the risk of several common types of arthritis, including osteoarthritis, rheumatoid arthritis (RA), and psoriatic arthritis (PsA). Genetic variants from genome-wide association studies (GWAS) of LSBs for time spent on television watching, computer use, and driving were obtained from the UK Biobank. Summarized GWAS data of OA [overall, OA of the hip (HOA), and OA of the knee (KOA)], RA [overall, seronegative RA (nRA) and seropositive RA], and PsA was also acquired from the FinnGen Biobank Analysis. Causal Analysis Using Summary Effect Estimates (CAUSE) were further applied to verify the causality.

RESULTS

UVMR results provided evidence for the causal relationship of time spent on watching TV with overall OA [odds ratio (OR) = 1.80, 95% confidence interval (CI) = 1.45-2.23], KOA (OR = 1.86, 95% CI = 1.45-2.39) and HOA (IVW-fixed: OR = 1.65, 95% CI =1.20-2.26). Similar associations were observed in the TV-overall RA and TV-pRA, and TV-PsA, but the CAUSE method results only supported the causal association of time spent TV watching with OA and KOA. Moreover, MVMR results showed indicated an independent causal effect of TV watching on OA (overall, KOA, and HOA).

CONCLUSION

This study demonstrated the genetic causal association of prolonged TV watching time with overall OA and KOA risks.

Musculoskeletal exercise: Its role in promoting health and longevity

Resistance training (RT) is an often ignored but essential component of physical health.. The functioning of the musculoskeletal system declines with age, resulting in sarcopenia, loss of muscle strength and power, decrease in muscle flexibility and balance. Other pertinent age-related changes include decline in basal metabolic rate, increase in fat mass, and decrease in bone mineral density. Such primary aging can be accentuated by the concomitant presence of comorbid conditions, such as insulin resistance and diabetes, obesity, inflammatory conditions, and physical inactivity (PI). The latter is often promoted by the presence of musculoskeletal conditions, such as osteoarthritis, back pain, and osteoporosis, which are quite common in society. RT can diminish long-term joint stress, "resist" age-related physiological deterioration and improve health outcomes through its ability to increase muscle strength and mass, balance the distribution of forces within a joint, increase basal metabolic rate and bone density, reduce body fat and cardiac risk factors, enhance endothelial function, and promote cognitive function and psychological well-being. Accordingly, health providers should screen for PI, lack of RT, and mobility risks using short screening questions, and employ simple functional tests, when indicated, to evaluate patients for impairment in gait, muscle strength, flexibility, and balance. This review also provides general principles for initiating and conducting RT and provides general and specific examples of resistance training programs, which should be individualized for patients through the evaluation and guidance by appropriate health providers, physical therapists, and certified trainers.

Associations of Mutually Exclusive Categories of Physical Activity and Sedentary Behavior with Body Composition and Fall Risk in Older Women: A Cross-Sectional Study

The individual effects of physical activity (PA) and sedentary behavior (SB) on health are well-recognized. However, little is known about the extent to which different combinations of these behaviors are associated with body composition and fall risk in older adults. This cross-sectional study examined the associations of mutually exclusive categories of PA and SB with body composition and fall risk in older women. Accelerometer-measured PA, body composition and fall risk (static and dynamic balance) parameters were assessed among 94 community-dwelling older women. The participants were categorized into four groups: active-low sedentary, active-high sedentary, inactive-low sedentary and inactive-high sedentary (active: ≥150 min/week moderate-to-vigorous PA (MVPA); low sedentary: lowest tertile of SB and light PA ratio). Compared to the inactive-high sedentary group, more favorable body composition and dynamic balance results were found in the active-low sedentary (body fat mass index (BFMI): β = -4.37, p = 0.002; skeletal muscle mass index (SMI): β = 1.23, p = 0.017; appendicular lean mass index (ALMI): β = 1.89, p = 0.003; appendicular fat mass index (AFMI): β = -2.19, p = 0.003; sit-to-stand: β = 4.52, p = 0.014) and inactive-low sedentary (BFMI: β = -3.14, p = 0.007; SMI: β = 1.05, p = 0.014; AFMI: β = -1.74, p = 0.005, sit-to-stand: β = 3.28, p = 0.034) groups. Our results suggest that PA programs focusing on concurrently achieving sufficient MVPA and reduced SB might promote a healthy body composition and reduced fall risk among older adults.

Environmental Risk Factors for Osteoarthritis: The Impact on Individuals with Knee Joint Injury

Osteoarthritis is a debilitating chronic condition involving joint degeneration, impacting over 300 million people worldwide. This places a high social and economic burden on society. The knee is the most common joint impacted by osteoarthritis. A common cause of osteoarthritis is traumatic joint injury, specifically injury to the anterior cruciate ligament. The purpose of this review is to detail the non-modifiable and modifiable risk factors for osteoarthritis with particular focus on individuals after anterior cruciate ligament injury. After reading this, health care providers will better comprehend the wide variety of factors linked to osteoarthritis.

FDA/Arthritis Foundation osteoarthritis drug development workshop recap: Assessment of long-term benefit

OBJECTIVE

To summarize proceedings of a workshop convened to discuss the current state of science in the disease of osteoarthritis (OA), identify the knowledge gaps, and examine the developmental and regulatory challenges in bringing these products to market.

DESIGN

Summary of the one-day workshop held virtually on June 22nd, 2021.

RESULTS

Speakers selected by the Planning Committee presented data on the current approach to assessment of OA therapies, biomarkers in OA drug development, and the assessment of disease progression and long-term benefit.

CONCLUSIONS

Demonstrated by numerous failed clinical trials, OA is a challenging disease for which to develop therapeutics. The challenge is magnified by the slow time of onset of disease and the need for clinical trials of long duration and/or large sample size to demonstrate the effect of an intervention. The OA science community, including academia, pharmaceutical companies, regulatory agencies, and patient communities, must continue to develop and test better clinical endpoints that meaningfully reflect disease modification related to long-term patient benefit.

Predictors of resilience in older adults with lower limb osteoarthritis and persistent severe pain

BACKGROUND

Resilience refers to the process in which people function well despite adversity. Persistent severe pain may be considered an adversity in people with lower limb osteoarthritis (LLOA). The objectives of this study are: (1) to identify what proportion of older adults with LLOA and persistent severe pain show good functioning; and (2) to explore predictors of resilience.

METHODS

Data from the European Project on OSteoArthritis (EPOSA) were used involving standardized data from six European population-based cohort studies. LLOA is defined as clinical knee and/or hip osteoarthritis. Persistent severe pain is defined as the highest tertile of the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index both at baseline and follow-up. Resilience is defined as good physical, mental or social functioning at follow-up despite having LLOA with persistent severe pain.

RESULTS

In total, 95 (14.9%) out of 638 individuals with LLOA had persistent severe pain. Among these, 10 (11.0%), 54 (57.4%) and 49 (53.8%) had good physical, mental and social functioning, respectively. Only 4 individuals (4.5%) were resilient in all three domains of functioning. Younger age, male sex, higher education, higher mastery, smoking and alcohol use, higher physical activity levels, absence of chronic diseases, and more contacts with friends predicted resilience in one or more domains of functioning.

CONCLUSIONS

Few people with LLOA and persistent severe pain showed good physical functioning and about half showed good mental or social functioning. Predictors of resilience differed between domains, and might provide new insights for treatment.

Linking physical activity with clinical, functional, and structural outcomes: an evidence map using the Osteoarthritis Initiative

Physical activity is consistently recommended across clinical practice guidelines for managing knee osteoarthritis, yet prescription rates are low. Evidence mapping uses a systematic approach to visually illustrate and summarize published evidence, highlight gaps in the literature, and formulate research questions. The purpose of this study was to review and summarize evidence published from the Osteoarthritis Initiative (OAI) linking physical activity with clinical, functional, and structural knee osteoarthritis outcomes. Electronic databases were searched until June 2021. Studies from the OAI reporting subjective (Physical Activity Scale for the Elderly, PASE) or objective (accelerometry) physical activity data were included. Scatter plots were created to represent each outcome group (clinical, functional, structural) and physical activity measure (PASE, accelerometry) to map the evidence by the directional effect (positive, interaction, negative, or no effect) associated with physical activity. Forty-two articles were included in this review. Physical activity was quantified using PASE (n = 21), accelerometry (n = 20), or both (n = 1). Studies reported consistently positive physical activity effects on clinical (n = 22) and functional (n = 20) outcomes, with few exceptions. Structural (n = 15) outcomes were largely reported as interaction effects by physical activity intensity or sex, or as no significant effect. A network of interconnected outcomes emerged, with clinical and functional outcomes often reported together, and structural outcomes reported individually. This study provides an overview of current evidence linking physical activity to multiple interrelated knee osteoarthritis outcomes using an OAI-driven model. These evidence maps can be used as a framework to guide future investigations of the effects of physical activity on knee osteoarthritis.