Sedentary behaviour and risk of all-cause, cardiovascular and cancer mortality, and incident type 2 diabetes: a systematic review and dose response meta-analysis

Sedentary behavior and physiological health determinants in male and female college students

BACKGROUND

Sedentary behaviors are associated with numerous adverse physiological health outcomes, morbidity and mortality, although with limited knowledge in young adults.

AIM

To assess the association between sedentary behavior, muscular strength and body composition in male and female young adult college students.

METHODS

A cross-sectional pilot study was conducted among 94 college students (20.2 ± 1.6 years, 46 males and 48 females) from a University in the Mid-Atlantic region, US. Students were assessed for sedentary behavior, physical activity and objective physiological variables including lean body mass (LBM), fat% and muscular strength [1-Repetition Maximum (1-RM)]. Descriptive statistics and linear regression analysis were conducted.

RESULTS

Sedentary behavior (sitting time ≥ 6 h/day) was prevalent in 69% of females and in 46% of males, p = .036, although most students (84-94%) met the physical activity recommendations. Sitting time inversely correlated with LBM (r = -0.58, p = .01) and trending for positive correlation with fat% in females, whereas in males, sitting time inversely correlated with 1-RM upper body strength (r = -0.46, p = .017). Female students who sat ≥7.5 h/day had approximately 10-fold increased chance of being obese [odds ratio = 9.6, 95% confidence interval (1.5 to 62.7), p = .019] compared to non-sedentary.

CONCLUSIONS

Although most students were physically active, considerable prevalence of sedentary behavior was observed. The novel findings showed that, sedentary behavior was associated with compromised physiological health determinants of body composition in females and muscular strength in males. Reducing sedentary behavior among active college students could be a public health strategy for health promotion and chronic disease prevention.

Unprompted vigorous physical activity is associated with higher levels of subsequent sedentary behaviour in participants with low cardiorespiratory fitness: a cross-sectional study

Performing physical activity is considered health promoting but may induce a need for subsequent rest periods. This study aimed to determine the within-day interactions between vigorous physical activity (VPA) and sedentary behaviour (SB) in participants with low cardiorespiratory fitness. We tested the hypothesis that VPA is associated with a temporary subsequent increase in SB. One week of accelerometer data containing a minimum of one 10-min bout of VPA from 62 participants with low cardiorespiratory fitness (31-50 years old) were obtained from the MILE study. A comparison of SB was made between days with a bout of VPA and days without (control). Due to a positive association between VPA and number and duration of sedentary bouts, the time accumulated in both uninterrupted and total sedentary bouts were 27 (95% CI, 10-45) min and 29 (95% CI, 9-50) min higher on VPA days compared to control days (P < 0.05). Our results indicate that in participants with low cardiovascular fitness, unprompted VPA is positively associated with an increase in subsequent sedentary time. We propose that such VPA-associated sedentary time may be viewed as part of a healthy activity pattern.

Participation in Physical Activity is Associated with Sexual Activity in Older English Adults

Physical activity (PA) is a potential modifiable correlate of the age-related decline in sexual function, but no studies have explicitly tested this. This study aimed to examine associations between PA, television viewing (TV) time and sexual activity, problems, and concerns. Data were from 7038 men and women aged ≥50 years participating in the English Longitudinal Study of Ageing. PA and TV viewing time were self-reported. Sexual behaviour and concerns were assessed by self-completion questionnaire. Covariates included age, partnership status, socio-economic status, limiting long-standing illness, smoking status, alcohol intake and depressive symptoms. The odds of reporting any sexual activity were increased among individuals who participated in moderate (OR = 1.64, 95% CI: 1.24–2.15 in men) or vigorous (OR = 2.06, 95% CI: 1.50–2.84 in men, OR = 1.42, 95% CI: 1.09–1.85 in women) PA at least once a week. Erectile difficulties were less common among men who were active (OR = 0.58, 95% CI: 0.44–0.77 for vigorous PA). Women who watched ≥6 h of TV/day had lower odds of thinking about sex frequently (OR = 0.69, 95% CI: 0.50–0.96) or, if they did not live with a partner, being sexually active (OR = 0.40, 95% CI: 0.22–0.72). Encouraging older adults to be more physically active could help to improve sexual relationships and, as a result, mental health and wellbeing.

Chronic diseases and objectively monitored physical activity profile among aged individuals - a cross-sectional twin cohort study

INTRODUCTION

High physical activity (PA) at old age indicates good functional capacity enabling independent living. We investigated how different disease conditions are associated with measured PA indicators in old women and men, and whether they recognize this association.

MATERIALS AND METHODS

This cross-sectional twin cohort study in Finland comprised 779 individuals (276 complete twin pairs, including 117 monozygotic pairs), who participated in hip-worn accelerometer monitoring of PA and responded to questions on diseases and mobility limitations at mean age of 73 (range 71-75).

RESULTS

Of the participants, 23.2% reported having a disease restricting mobility. With sex and age in the regression model, the reported disease restricting mobility explained 11.8% of the variation in moderate-to-vigorous PA (MVPA) and 10.4% of the variation in daily steps. Adding stepwise other self-reported diseases and body mass index to the model increased the explanatory power for MVPA up to 18.5% and 25.5%, and for daily steps up to 16.0% and 20.7%, respectively. In the co-twin control analysis the PA differences were smaller in disease-discordant monozygotic than dizygotic pairs.

CONCLUSIONS

Chronic disease conditions are associated with low PA, which individuals may not always recognize. Shared genetic factors may explain part of the associations. Key messages Among community-dwelling older men and women one-fourth of the variation in objectively measured moderate-to-vigorous physical activity is accounted for by age, sex, body mass index and self-reported diseases. Occurrence of chronic diseases is associated with low physical activity and individuals do not always recognize this. Healthcare professionals should pay attention to the low physical activity and mobility of individuals with chronic disease conditions before these result in limitations in independent living.

Factors influencing sedentary behaviour: A system based analysis using Bayesian networks within DEDIPAC

Background

Decreasing sedentary behaviour (SB) has emerged as a public health priority since prolonged sitting increases the risk of non-communicable diseases. Mostly, the independent association of factors with SB has been investigated, although lifestyle behaviours are conditioned by interdependent factors. Within the DEDIPAC Knowledge Hub, a system of sedentary behaviours (SOS)-framework was created to take interdependency among multiple factors into account. The SOS framework is based on a system approach and was developed by combining evidence synthesis and expert consensus. The present study conducted a Bayesian network analysis to investigate and map the interdependencies between factors associated with SB through the life-course from large scale empirical data.

Methods

Data from the Eurobarometer survey (80.2, 2013) that included the International physical activity questionnaire (IPAQ) short as well as socio-demographic information and questions on perceived environment, health, and psychosocial information were enriched with macro-level data from the Eurostat database. Overall, 33 factors were identified aligned to the SOS-framework to represent six clusters on the individual or regional level: 1) physical health and wellbeing, 2) social and cultural context, 3) built and natural environment, 4) psychology and behaviour, 5) institutional and home settings, 6) policy and economics. A Bayesian network analysis was conducted to investigate conditional associations among all factors and to determine their importance within these networks. Bayesian networks were estimated for the complete (23,865 EU-citizens with complete data) sample and for sex- and four age-specific subgroups. Distance and centrality were calculated to determine importance of factors within each network around SB.

Results

In the young (15–25), adult (26–44), and middle-aged (45–64) groups occupational level was directly associated with SB for both, men and women. Consistently, social class and educational level were indirectly associated within male adult groups, while in women factors of the family context were indirectly associated with SB. Only in older adults, factors of the built environment were relevant with regard to SB, while factors of the home and institutional settings were less important compared to younger age groups.

Conclusion

Factors of the home and institutional settings as well as the social and cultural context were found to be important in the network of associations around SB supporting the priority for future research in these clusters. Particularly, occupational status was found to be the main driver of SB through the life-course. Investigating conditional associations by Bayesian networks gave a better understanding of the complex interplay of factors being associated with SB. This may provide detailed insights in the mechanisms behind the burden of SB to effectively inform policy makers for detailed intervention planning. However, considering the complexity of the issue, there is need for a more comprehensive system of data collection including objective measures of sedentary time.

Poor Adherence to International Cancer Prevention Recommendations Among Patients With Prostate Cancer: First Results From the MARTINI-Lifestyle Cohort

BACKGROUND

Promotion of a healthy lifestyle in patients with prostate cancer (PCa) has gained traction to increase patient investment in his/her health care practices, improve patient quality of life, and improve survival outcomes.

OBJECTIVE

To investigate adherence of patients with PCa to healthy lifestyle recommendations from the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR).

DESIGN, SETTING, AND PARTICIPANTS

A total of 2227 men with PCa scheduled for radical prostatectomy in the Martini-Klinik at the University Hospital Hamburg-Eppendorf, Hamburg, Germany between January 2016 and December 2017.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Age and clinical characteristics were collected at the time of the diagnosis. Assessment of diet and physical activity data were obtained via e-mail surveys using validated questionnaires developed for the European Prospective Investigation into Cancer and Nutrition (EPIC) study [food frequency questionnaire, version 2 (FFQ2), EPIC-Physical Activity Questionnaire (EPIC-PAQ)]. Baseline characteristics were calculated as means and standard deviations for continuous data or counts and percentages for categorical data.

RESULTS AND LIMITATIONS

Patients followed 3.3 (±1.5) of the 10 WCRF/AICR recommendations. None of the participants reached all goals; 67.3% of the patients did not fulfill the criteria of a healthy normal weight, 33.5% reported no exercise at all, and 49.6% were characterized as current or ex-smokers. As to nutritional goals, 75.4% did not meet the recommended intake of meat, 88.8% reported a low consumption of fruit and vegetables, and 86% did not achieve the recommended fiber intake. Because these analyses are based on self-reported data of diet and lifestyle, a bias toward underreporting cannot be excluded.

CONCLUSIONS

First results of the MARTINI-Lifestyle cohort show that adherence to the AICR/WCRF recommendations for cancer prevention is poor.

PATIENT SUMMARY

Patients with prostate cancer scheduled for surgery do not adhere to cancer prevention guidelines. Thus, improving lifestyle habits may provide significant impact on patient health and quality of life.

Differences in objectively measured physical activity and sedentary behaviour between white Europeans and south Asians recruited from primary care: cross-sectional analysis of the PROPELS trial

BACKGROUND

Self-reported data have consistently shown South Asians (SAs) to be less physically active than White Europeans (WEs) in developed countries, however objective data is lacking. Differences in sedentary time have not been elucidated in this population. This study aimed to quantify differences in objectively measured physical activity and sedentary behaviour between WEs and SAs recruited from primary care and to investigate differences in demographic and lifestyle correlates of these behaviours.

METHODOLOGY

Baseline data were utilised from a randomised control trial recruiting individuals identified at high risk of type 2 diabetes from primary care. Light intensity physical activity, moderate-to-vigorous intensity physical activity (MVPA) and steps were measured using the Actigraph GT3X+, while sitting, standing and stepping time were measured using the activPAL3™. Devices were worn concurrently for seven days. Demographic (employment, sex, age, education, postcode) and behavioural (fruit and vegetable consumption, alcohol consumption, smoking status) characteristics were measured via self and interview administered questionnaires.

RESULTS

A total of 963 WE (age = 62 ± 8, female 51%) and 289 SA (age = 55 ± 11, female 43%) were included. Compared to WEs, SAs did less MVPA (24 vs 33 min/day, p = 0.001) and fewer steps (6404 vs 7405 per day, p ≤ 0.001), but sat less (516 vs 552 min/day, p ≤ 0.001) and stood more (328 vs 283 min/day, p ≤ 0.001). Ethnicity also modified the extent to which demographic and behavioural factors act as correlates of physical activity and sedentary behaviour. Differences between sex in levels of MVPA and sitting time were greater in SAs compared to WEs, with SA women undertaking the least amount of MVPA (19 min/day), the least sitting time (475 min/day) and most standing time (377 min/day) than any other group. Smoking and alcohol status also acted as stronger correlates of sitting time in SAs compared to WEs. In contrast, education level acted as a stronger correlate of physical activity in WEs compared to SAs.

CONCLUSION

SAs were less active yet less sedentary than WEs, which demonstrates the need to tailor the behavioural targets of interventions in multi-ethnic communities. Common correlates of physical activity and sedentary behaviour also differed between ethnicities.

TRIAL REGISTRATION

ISRCTN83465245 Trial registration date: 14/06/2012.

Associations of Physical Behaviours and Behavioural Reallocations with Markers of Metabolic Health: A Compositional Data Analysis

Standard statistical modelling has shown that the reallocation of sitting time to either standing or stepping may be beneficial for metabolic health. However, this overlooks the inherent dependency of time spent in all behaviours. The aim is to examine the associations between physical behaviours and markers of metabolic health (fasting glucose, fasting insulin, 2-h glucose, 2-h insulin, Homeostasis Model Assessment of Insulin Sensitivity (HOMA-IS), Matsuda Insulin Sensitivity Index (Matsuda-ISI) while quantifying the associations of reallocating time from one physical behaviour to another using compositional analysis. Objectively measured physical behaviour data were analysed (n = 435) using compositional analysis and compositional isotemporal substitutions to estimate the association of reallocating time from one behaviour to another in a population at high risk of type 2 diabetes mellitus (T2DM). Stepping time was associated with all markers of metabolic health relative to all other behaviours. Reallocating 30 min from sleep, sitting, or standing to stepping was associated with 5⁻6 fold lower 2-h glucose, 15⁻17 fold lower 2-h insulin, and higher insulin sensitivity (10⁻11 fold via HOMA-IS, 12⁻15 fold via Matsuda-ISI). Associations of reallocating time from any behaviour to stepping were maintained for 2-h glucose, 2-h insulin, and Matsuda-ISI after further adjusting for body mass index (BMI). Relocating time from stepping into sleep, sitting, or standing was associated with lower insulin sensitivity. Stepping time may be the most important behavioural composition when promoting improved metabolic health in adults at risk of T2DM.

Effectiveness of the Stand More AT (SMArT) Work intervention: cluster randomised controlled trial

OBJECTIVES

To evaluate the impact of a multicomponent intervention (Stand More AT (SMArT) Work) designed to reduce sitting time on short (three months), medium (six months), and longer term (12 months) changes in occupational, daily, and prolonged sitting, standing, and physical activity, and physical, psychological, and work related health.

DESIGN

Cluster two arm randomised controlled trial.

SETTING

National Health Service trust, England.

PARTICIPANTS

37 office clusters (146 participants) of desk based workers: 19 clusters (77 participants) were randomised to the intervention and 18 (69 participants) to control.

INTERVENTIONS

The intervention group received a height adjustable workstation, a brief seminar with supporting leaflet, workstation instructions with sitting and standing targets, feedback on sitting and physical activity at three time points, posters, action planning and goal setting booklet, self monitoring and prompt tool, and coaching sessions (month 1 and every three months thereafter). The control group continued with usual practice.

MAIN OUTCOME MEASURES

The primary outcome was occupational sitting time (thigh worn accelerometer). Secondary outcomes were objectively measured daily sitting, prolonged sitting (≥30 minutes), and standing time, physical activity, musculoskeletal problems, self reported work related health (job performance, job satisfaction, work engagement, occupational fatigue, sickness presenteeism, and sickness absenteeism), cognitive function, and self reported psychological measures (mood and affective states, quality of life) assessed at 3, 6, and 12 months. Data were analysed using generalised estimating equation models, accounting for clustering.

RESULTS

A significant difference between groups (in favour of the intervention group) was found in occupational sitting time at 12 months (-83.28 min/workday, 95% confidence interval -116.57 to -49.98, P=0.001). Differences between groups (in favour of the intervention group compared with control) were observed for occupational sitting time at three months (-50.62 min/workday, -78.71 to -22.54, P<0.001) and six months (-64.40 min/workday, -97.31 to -31.50, P<0.001) and daily sitting time at six months (-59.32 min/day, -88.40 to -30.25, P<0.001) and 12 months (-82.39 min/day, -114.54 to -50.26, P=0.001). Group differences (in favour of the intervention group compared with control) were found for prolonged sitting time, standing time, job performance, work engagement, occupational fatigue, sickness presenteeism, daily anxiety, and quality of life. No differences were seen for sickness absenteeism.

CONCLUSIONS

SMArT Work successfully reduced sitting time over the short, medium, and longer term, and positive changes were observed in work related and psychological health.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN10967042.

A three arm cluster randomised controlled trial to test the effectiveness and cost-effectiveness of the SMART Work & Life intervention for reducing daily sitting time in office workers: study protocol

BACKGROUND

Office-based workers typically spend 70-85% of working hours, and a large proportion of leisure time, sitting. High levels of sitting have been linked to poor health. There is a need for fully powered randomised controlled trials (RCTs) with long-term follow-up to test the effectiveness of interventions to reduce sitting. This paper describes the methodology of a three-arm cluster RCT designed to determine the effectiveness and cost-effectiveness of the SMART Work & Life intervention, delivered with and without a height-adjustable desk, for reducing daily sitting.

METHODS/DESIGN

A three-arm cluster RCT of 33 clusters (660 council workers) will be conducted in three areas in England (Leicester; Manchester; Liverpool). Office groups (clusters) will be randomised to the SMART Work & Life intervention delivered with (group 1) or without (group 2) a height-adjustable desk or a control group (group 3). SMART Work & Life includes organisational (e.g., management buy-in, provision/support for standing meetings), environmental (e.g., relocating waste bins, printers), and group/individual (education, action planning, goal setting, addressing barriers, coaching, self-monitoring, social support) level behaviour change strategies, with strategies driven by workplace champions. Baseline, 3, 12 and 24 month measures will be taken.

PRIMARY OUTCOME

Objectively measured daily sitting time (activPAL3).

SECONDARY OUTCOMES

objectively measured sitting, standing, stepping, prolonged sitting and moderate-to-vigorous physical activity time and number of steps at work and daily; objectively measured sleep (wrist accelerometry). Adiposity, blood pressure, fasting glucose, glycated haemoglobin, cholesterol (total, HDL, LDL) and triglycerides will be assessed from capillary blood samples. Questionnaires will examine dietary intake, fatigue, musculoskeletal issues, job performance and satisfaction, work engagement, occupational and general fatigue, stress, presenteeism, anxiety and depression and sickness absence (organisational records). Quality of life and resources used (e.g. GP visits, outpatient attendances) will also be assessed. We will conduct a full process evaluation and cost-effectiveness analysis.

DISCUSSION

The results of this RCT will 1) help to understand how effective an important simple, yet relatively expensive environmental change is for reducing sitting, 2) provide evidence on changing behaviour across all waking hours, and 3) provide evidence for policy guidelines around population and workplace health and well-being.

TRIAL REGISTRATION

ISRCTN11618007 . Registered on 21 January 2018.

Physical activity during pregnancy is associated with a lower prevalence of gestational diabetes mellitus in Vietnam

AIMS

To assess the association between physical activity (PA) during pregnancy and the prevalence of gestational diabetes mellitus (GDM) accounting for sitting time.

METHODS

The study used data from a cohort study of 2030 pregnant women in Vietnam. Women were recruited from six hospitals in Ha Noi, Hai Phong, and Ho Chi Minh City. Baseline measurements including PA and GDM were taken at 24-28 weeks of gestation. PA was assessed during the past 3 months before the interview using the interviewer-administered Pregnancy Physical Activity Questionnaire. GDM was diagnosed at 24-28 weeks of gestation using the 2013 World Health Organization criteria.

RESULTS

1987 out of 2030 pregnant women were included in the final analysis, of which 432 had GDM (21.7%). Women undertaking the highest level (upper tertile) of PA during pregnancy appeared to have a lower risk of GDM [odds ratio (OR) 0.70, 95% confidence interval (CI) 0.53-0.94, P_trend 0.017] when compared to those at the lowest tertile of PA. Similarly, women with increased levels of moderate-intensive activity and household/caregiving activity during pregnancy were associated with reduced risks of GDM (OR 0.66, 95% CI 0.50-0.86, P_trend 0.002 and OR 0.72, 95% CI 0.55-0.95, P_trend 0.020, respectively). These apparent inverse associations were not attenuated by their sitting time. There were no significant associations between sitting time, light-intensity activity, vigorous-intensity activity, occupation, sports/exercise, commuting, or meeting exercise guidelines and GDM risk.

CONCLUSIONS

High levels of PA, particularly moderate-intensity and household/caregiving activities during pregnancy were associated with a lower prevalence of GDM independent of sitting time.

Modalities for assessing the nutritional status in patients with diabetes and cancer

Epidemiological data have shown that an increased body mass index (BMI) is associated with a higher risk of various cancers, especially in obese diabetic patients. However, oncologic patients often present nutritional alterations that can worsen their prognosis. The aim of this review is to propose the use of cheaper and easy to use tools to assess the nutritional status of patients with cancer with altered glucose metabolism. Based on a literature review, we propose anthropometric measures to classify the degree of malnutrition. Moreover, the Karnofsky Performance Status (KPS) and the Eastern Cooperative Oncology Group's performance index (ECOG) are useful to assess the functional status of the body; the achievement of nutritional needs can be analysed with the PG-SGA questionnaire, while the quality of life can be investigated using the DTSQ, SF36, EQ-5D questionnaires and the Edmonton Symptom Assessment System. Pre-albumin dosage and lymphocyte count are proposed as nutritional parameters. The degree of hydration can be evaluated through the Bio-Impedance Test (BIA), and energy intake through the dairy food diary, which considers the type of nutrition and the consistency of the meals. It is possible to use a score for each tool used, which is useful to plan an adequate nutritional intervention.

Do the associations of sedentary behaviour with cardiovascular disease mortality and cancer mortality differ by physical activity level? A systematic review and harmonised meta-analysis of data from 850 060 participants

Objective

To examine whether the associations between sedentary behaviours (ie, daily sitting/TV-viewing time) and mortality from cardiovascular disease (CVD) and cancer differ by different levels of physical activity (PA).

Design

Harmonised meta-analysis of prospective cohort studies. Data on exposure variables were harmonised according to a predefined protocol and categorised into four groups for sedentary behaviours and into quartiles of PA (MET-hour/week).

Data sources

PubMed, PsycINFO, Embase, Web of Science, Sport Discus and Scopus.

Eligibility criteria for selecting studies

Individual level data on both sedentary behaviours and PA and reported effect estimates for CVD or cancer mortality.

Results

Nine studies (n=850 060; deaths=25 730) and eight studies (n=777 696; deaths=30 851) provided data on sitting time and CVD and cancer mortality, respectively. Five studies had data on TV-viewing time and CVD (n=458 127; deaths=13 230) and cancer (n=458 091; deaths=16 430) mortality. A dose–response association between sitting time (9%–32% higher risk; p for trend <0.001) and TV time (3%–59% higher risk; p for trend <0.001) with CVD mortality was observed in the ‘inactive’, lowest quartile of PA. Associations were less consistent in the second and third quartiles of PA, and there was no increased risk for CVD mortality with increasing sedentary behaviours in the most active quartile. Associations between sedentary behaviours and cancer mortality were generally weaker; 6%–21% higher risk with longer sitting time observed only in the lowest quartile of PA.

Conclusion

PA modifies the associations between sedentary behaviours and CVD and cancer mortality. These findings emphasise the importance of higher volumes of moderate and vigorous activity to reduce, or even eliminate these risks, especially for those who sit a lot in their daily lives.

Is the time right for quantitative public health guidelines on sitting? A narrative review of sedentary behaviour research paradigms and findings

Sedentary behaviour (SB) has been proposed as an 'independent' risk factor for chronic disease risk, attracting much research and media attention. Many countries have included generic, non-quantitative reductions in SB in their public health guidelines and calls for quantitative SB targets are increasing. The aim of this narrative review is to critically evaluate key evidence areas relating to the development of guidance on sitting for adults. We carried out a non-systematic narrative evidence synthesis across seven key areas: (1) definition of SB, (2) independence of sitting from physical activity, (3) use of television viewing as a proxy of sitting, (4) interpretation of SB evidence, (5) evidence on 'sedentary breaks', (6) evidence on objectively measured sedentary SB and mortality and (7) dose response of sitting and mortality/cardiovascular disease. Despite research progress, we still know little about the independent detrimental health effects of sitting, and the possibility that sitting is mostly the inverse of physical activity remains. Unresolved issues include an unclear definition, inconsistencies between mechanistic and epidemiological studies, over-reliance on surrogate outcomes, a very weak epidemiological evidence base to support the inclusion of 'sedentary breaks' in guidelines, reliance on self-reported sitting measures, and misinterpretation of data whereby methodologically inconsistent associations are claimed to be strong evidence. In conclusion, public health guidance requires a consistent evidence base but this is lacking for SB. The development of quantitative SB guidance, using an underdeveloped evidence base, is premature; any further recommendations for sedentary behaviour require development of the evidence base and refinement of the research paradigms used in the field.

Correlates of sedentary behaviour and light physical activity in people living with rheumatoid arthritis: protocol for a longitudinal study

BACKGROUND

Sedentary behaviour (SB) is associated with adverse health outcomes in the general population. Replacing sedentary time with light intensity physical activity (LPA) has been linked with improvements in all-cause and cardiovascular disease mortality in adults. People with Rheumatoid Arthritis (RA) typically spend long periods of time sedentary, but the health consequences of 'too much sitting', and possible benefits of LPA, have not been fully explored in this population. Moreover, little is known regarding the determinants of these behaviours among people living with RA, and such knowledge is required for the development of effective behavioural interventions.

AIMS

To examine longitudinal relationships between: 1) objectively-assessed SB/LPA with health outcomes in RA, 2) hypothesised determinants of SB/LPA with objectively-assessed SB/LPA in RA.

METHODS

This longitudinal study will secure assessments at baseline (Time 1) and 6-month follow-up (Time 2) from RA patients. At both time points, physical assessments will be undertaken, and questionnaires administered to measure physical (e.g., percentage body fat, disease activity, physical function, pain) and psychological (e.g., depression, anxiety, vitality) health outcomes. Additional questionnaires will be administered to establish hypothesised determinants (i.e., psychosocial, individual differences, and physical environmental). Participants will wear the ActiGraph GT3X accelerometer and activPAL3μTM for 7 days to objectively measure SB and LPA.

DISCUSSION

Findings will elucidate the health correlates of SB in RA, as well as the relevance of interventions targeting reductions in SB by promoting LPA. Results will also assist in identifying intervention targets (i.e., determinants), with the potential to encourage SB change in RA.