Acceptability and optimisation of resources to support antidepressant cessation: a qualitative think-aloud study with patients in Australian primary care.

BACKGROUND: Stopping long-term (>12 months) antidepressant use can be difficult due to unpleasant withdrawal symptoms. Many people do not recognise withdrawal symptoms or understand how to minimise them while safely discontinuing antidepressants. To address the gaps, the authors developed the 'Redressing long-term antidepressant use' (RELEASE) resources, comprising a medicines information brochure, a decision aid, and drug- specific hyperbolic tapering protocols. AIM: To explore patients' acceptability of the RELEASE resources to optimise their use and impact. DESIGN AND SETTING: A think-aloud interview study among adults with lived experience of long-term antidepressant use conducted in south-east Queensland, Australia, between November 2021 and June 2022. METHOD: Participants were purposively sampled from general practices and interviewed face-to-face or via videoconferencing. Participants verbalised their thoughts, impressions, and feelings while engaging with each resource. Interviews were analysed using a deductive coding framework, including codes related to acceptability and optimisation. Interviews were analysed in a series of four tranches, with iterative modifications made to resources after each tranche. RESULTS: Participants (n = 14) reported the resources to be relevant, informative, motivational, and usable. Participants' comments informed modifications, including changes to wording, content order, and layout. Several participants expressed frustration that they had not had these resources earlier, with one reporting the information could have been 'life changing'. Many commented on the need for these resources to be widely available to both patients and doctors. CONCLUSION: The RELEASE resources were found to be acceptable, useful, and potentially life changing. The effectiveness of these consumer-informed resources in supporting safe cessation of long-term antidepressants is currently being tested in general practice.

Statistical methodologies for evaluation of the rate of persistence of Ebola virus in semen of male survivors in Sierra Leone.

The 2013-2016 Ebola virus (EBOV) outbreak in West Africa was the largest and most complex outbreak ever, with a total number of cases and deaths higher than in all previous EBOV outbreaks combined. The outbreak was characterized by rapid spread of the infection in nations that were weakly prepared to handle it. EBOV ribonucleic acid (RNA) is known to persist in body fluids following disease recovery, and studying this persistence is crucial for controlling such epidemics. Observational cohort studies investigating EBOV persistence in semen require following up recently recovered survivors of Ebola virus disease (EVD), from recruitment to the time when their semen tests negative for EBOV, the endpoint being time-to-event. Because recruitment of EVD survivors takes place weeks or months following disease recovery, the event of interest may have already occurred. Survival analysis methods are the best suited for the estimation of the virus persistence in body fluids but must account for left- and interval-censoring present in the data, which is a more complex problem than that of presence of right censoring alone. Using the Sierra Leone Ebola Virus Persistence Study, we discuss study design issues, endpoint of interest and statistical methodologies for interval- and right-censored non-parametric and parametric survival modelling. Using the data from 203 EVD recruited survivors, we illustrate the performance of five different survival models for estimation of persistence of EBOV in semen. The interval censored survival analytic methods produced more precise estimates of EBOV persistence in semen and were more representative of the source population than the right censored ones. The potential to apply these methods is enhanced by increased availability of statistical software to handle interval censored survival data. These methods may be applicable to diseases of a similar nature where persistence estimation of pathogens is of interest.

A protocol for longitudinal monitoring of individual building occupants and their environments.

Buildings account for approximately 40% of the energy consumption across the European Union, so there is a requirement to strive for better energy performance to reduce the global impact of urbanised societies. However, energy performant buildings can negatively impact building occupants (e.g., comfort, health and/or wellbeing) due to a trade-off between airtightness and air circulation. Thus, there is a need to monitor Indoor Environmental Quality (IEQ) to inform how it impacts occupants and hence redefine value within building performance metrics. An individualised study design would enable researchers to gain new insights into the effects of environmental changes on individuals for more targeted e.g., health interventions or nuanced and improved building design(s). This paper presents a protocol to conduct longitudinal monitoring of an individual and their immediate environment. Additionally, a novel approach to environmental perception gathering is proposed that will monitor environmental factors at an individual level to investigate subjective survey data pertaining to the participant's perceptions of IEQ (e.g., perceived air quality, thermal conditions, light, and noise). This protocol has the potential to expose time-differential phenomena between environmental changes and an individual's behavioural and physiological responses. This could be used to support building performance monitoring by providing an interventional assessment of building performance renovations. In the future it could also provide building scientists with a scalable approach for environmental monitoring that focuses specifically on individual health and wellbeing.

Exploring Symptom Fluctuations and Triggers in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Using Novel Patient-Centred N-of-1 Observational Designs: A Protocol for a Feasibility and Acceptability Study.

BACKGROUND: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic condition of unknown aetiology associated with a range of disabling symptoms, including post-exertional malaise, chronic fatigue, musculoskeletal pain, orthostatic intolerance, unrefreshing sleep, and cognitive dysfunction. ME/CFS is a heterogeneous disorder, with significant variation in symptom type and severity between individuals, as well as within individuals over time. The diversity of ME/CFS symptom presentation makes management challenging; treatments supported by data from randomised controlled trials may not work for all individuals due to the variability in experienced symptoms. Studies using quantitative N-of-1 observational designs involve repeated outcome measurements in an individual over time and can generate rigorous individual-specific conclusions about symptom patterns and triggers in individuals with ME/CFS. This study aims to explore the feasibility and acceptability of using novel patient-centred N-of-1 observational designs to explore symptom fluctuations and triggers in ME/CFS at the individual level. METHODS AND ANALYSIS: Individuals with a medical diagnosis of ME/CFS will be recruited through ME/CFS patient organisations to participate in a series of patient-centred N-of-1 observational studies. Using a wrist-worn electronic diary, participants will complete ecological momentary assessments of fatigue, stress, mood, and cognitive demand, three times per day for a period of 6-12 weeks. Personally relevant symptoms and triggers will also be incorporated into the questionnaire design. Physical activity will be objectively measured via an integrated accelerometer. Feasibility and acceptability outcomes will be assessed including the percentage of diary entries completed, as well as recruitment and retention rate, feasibility of analysing and interpreting the data collected, and participant views about participation elicited via a post-study semi-structured interview. DISCUSSION: This study will assess the feasibility and acceptability of patient-centred N-of-1 observational studies to assess diseases with complex presentations such as ME/CFS, as well as provide individual-level evidence about fluctuations and triggers of ME/CFS symptoms that may aid self-management. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry: ACTRN12618001898246. Registered on 22 November 2018.

Establishment of an International Collaborative Network for N-of-1 Trials and Single-Case Designs.

In this article we briefly examine the unique features of Single-Case Designs (SCDs) (studies in a single participant), their history and current trends, and real-world clinical applications. The International Collaborative Network for N-of-1 Trials and Single-Case Designs (ICN) is a formal collaborative network for individuals with an interest in SCDs. The ICN was established in 2017 to support the SCD scientific community and provide opportunities for collaboration, a global communication channel, resource sharing and knowledge exchange. In May 2021, there were more than 420 members in 31 countries. A member survey was undertaken in 2019 to identify priorities for the ICN for the following few years. This article outlines the key priorities identified and the ICN's progress to date in these key areas including network activities (developing a communications strategy to increase awareness, collecting/sharing a comprehensive set of resources, guidelines and tips, and incorporating the consumer perspective) and scientific activities (writing position papers and guest editing special journal issues, exploring key stakeholder perspectives about SCDs, and working to streamline ethical approval processes for SCDs). The ICN provides a practical means to engage with this methodology through membership. We encourage clinicians, researchers, industry, and healthcare consumers to learn more about and conduct SCDs, and to join us in our mission of using SCDs to improve health outcomes for individuals and populations.

Implementing a weight-specific quality-of-life tool for young people in primary health care: a qualitative study.

BACKGROUND: Obesity is thought to be one of the most serious global public health challenges of the 21st century. The primary care setting is important in terms of the diagnosis, education, and management of obesity in children and young people. This study explored the views of primary care clinicians on the implementation of a quality-of-life (QoL) tool to help young people and their families identify the impact of weight on QoL. AIM: To assess the acceptability and feasibility of implementing the Weight-specific Adolescent Instrument for Economic-evaluation (WAItE) QoL tool for young people aged 11-18 years in primary care. DESIGN & SETTING: Qualitative study in Northern England, UK METHOD: One-to-one, semi-structured interviews were conducted with a purposive sample of primary healthcare clinicians working in practices located in areas of varying deprivation in Northern England, UK. Interview transcripts were coded and analysed using framework analysis in NVivo (version 10). RESULTS: Participants (n = 16 GPs; n = 4 practice nurses) found the WAItE tool acceptable for them and their patients, and believed it was feasible for use in routine clinical practice. It was important to primary care clinicians that the tool would provide an overall QoL score that would be easy for GPs and nurses to interpret, to help them identify patients most in need of specialist help. CONCLUSION: This study has developed a platform for further research around QoL in young people who are overweight and obese. A future feasibility study will focus on implementing the tool in a small number of primary healthcare practices.

N-of-1 Trials in Healthcare.

Interest in N-of-1 trials and single-case designs is increasing worldwide, particularly due to the movement towards personalised medicine and patient-centred healthcare [...].

Breast cancer nursing interventions and clinical effectiveness: a systematic review.

OBJECTIVES: To examine the effects of nurse-led interventions on the health-related quality of life, symptom burden and self-management/behavioural outcomes in women with breast cancer. METHODS: Cochrane Controlled Register of Trials (CENTRAL), Cumulative Index to Nursing and Allied Health Literature (CINAHL), Medline and Embase databases were searched (January 1999 to May 2019) to identify randomised controlled trials (RCTs) and controlled before-and-after studies of interventions delivered by nurses with oncology experience for women with breast cancer. Risk of bias was evaluated using the revised Cochrane risk-of-bias tool for randomised trials. Intervention effects were synthesised by cancer trajectory using The Omaha System Intervention Classification Scheme. RESULTS: Thirty-one RCTs (4651 participants) were included. All studies were at risk of bias mainly due to inherent limitations such as lack of blinding and self-report data. Most studies (71%; n=22) reported at least one superior intervention effect. There were no differences in all outcomes between those who receive nurse-led surveillance care versus those who received physical led or usual discharge care. Compared with control interventions, there were superior teaching, guidance and counselling (63%) and case management (100%) intervention effects on symptom burden during treatment and survivorship. Effects of these interventions on health-related quality of life and symptom self-management/behavioural outcomes were inconsistent. DISCUSSION: There is consistent evidence from RCTs that nurse-led surveillance interventions are as safe and effective as physician-led care and strong evidence that nurse-led teaching, guidance and counselling and case management interventions are effective for symptom management. Future studies should ensure the incorporation of health-related quality of life and self-management/behavioural outcomes and consider well-designed attentional placebo controls to blind participants for self-report outcomes. PROTOCOL REGISTRATION: The International Prospective Register of Systematic Reviews (PROSPERO): CRD42020134914).

Analysing N-of-1 observational data in health psychology and behavioural medicine: a 10-step SPSS tutorial for beginners.

Background: N-of-1 observational studies can be used to describe natural intra-individual changes in health-related behaviours or symptoms over time, to test behavioural theories and to develop highly personalised health interventions. To date, N-of-1 observational methods have been under-used in health psychology and behavioural medicine. One reason for this may be the perceived complexity of statistical analysis of N-of-1 data. Objective: This tutorial paper describes a 10-step procedure for the analysis of N-of-1 observational data using dynamic regression modelling in SPSS for researchers, students and clinicians who are new to this area. The 10-step procedure is illustrated using real data from an N-of-1 observational study exploring the relationship between pain and physical activity. Conclusion: The availability of a user-friendly and robust statistical technique for the analysis of N-of-1 data using SPSS may foster increased awareness, knowledge and skills and establish N-of-1 designs as a useful methodological tool in health psychology and behavioural medicine.

Perceived influences on smoking behaviour and perceptions of dentist-delivered smoking cessation advice: A qualitative interview study.

OBJECTIVES: Many factors lead to the commencement and maintenance of smoking, and better understanding of these is relevant in the management of oral health, particularly as smoking cessation advice (SCA) from the dental team is a key component of patient care. Whereas most previous research has focused on dental professionals' perceptions of providing SCA, and identified facilitators and barriers to its provision, there has been more limited research focusing on patients' perceptions of receiving SCA in the dental context. Accordingly, this study aimed to explore the views of smokers with periodontitis receiving dentist-delivered SCA. METHODS: One-to-one, semi-structured interviews were conducted with a purposive sample of 28 adults who smoked tobacco and had recently received SCA during dentist-delivered periodontal therapy. Participants were sampled to reflect a range of ages and smoking behaviours. The interview schedule was based on the Theoretical Domains Framework (TDF) to explore perceived influences on smoking behaviour. Interviews also elicited participants' views on dentist-delivered SCA. Interviews were audio-recorded, transcribed verbatim and analysed thematically, drawing on the TDF. RESULTS: A broad range of perceived influences on smoking behaviour emerged from the data. Influences were allocated into seven prominent TDF domains: (i) social influences (family and friends, social pressures); (ii) social/professional role and identity (secret smoking); (iii) knowledge (experiences/perceptions of smoking cessation medications); (iv) environmental context and resources (social, home and workplace environment, cost of smoking, resentment towards authority); (v) emotions (stress management, pleasure of smoking and fear of quitting); (vi) nature of the behaviour (habitual nature, link to other behaviours, smell); and (vii) beliefs about consequences (health). With regard to views on dentist-delivered SCA, five main themes emerged: (i) opportunistic nature; (ii) personal impact and tangible prompts; (iii) positive context of cessation attempt; (iv) lack of previous support; and (v) differences between dentist-delivered SCA and other setting SCA. CONCLUSIONS: Smokers with periodontitis consider that a wide range of factors influence their smoking behaviour. Dentist-delivered SCA was supported and positively received. Important aspects included the opportunistic nature, personal impact, use of tangible prompts and positive context (of the quit attempt). Future research should focus on optimizing dentist-led smoking cessation intervention based on the themes identified.

Prostate cancer survivorship priorities for men and their partners: Delphi consensus from a nurse specialist cohort.

AIMS & OBJECTIVES: To describe the prostate cancer survivorship experience and priorities from the perspective of prostate cancer specialist nurses. BACKGROUND: Specialist nurses are providing long-term survivorship care to men and their partners however, few prostate cancer survivorship interventions are effective and priorities for nurse-led survivorship care are poorly understood. DESIGN: A three-round modified Delphi approach. METHODS: The study was conducted between 1 December 2018 and 28 February 2019 to develop a consensus view from an expert nurse cohort (43 prostate cancer specialist nurses: 90% response). First, participants described men's prostate cancer survivorship experience and priorities for improving care for men and partners. In subsequent rounds, participants identified key descriptors of the survivorship experience; rated priorities for importance and feasibility; and identified a top priority action for men and for partners. Thematic analysis and descriptive statistics were applied. Guidelines for Reporting Reliability and Agreement Studies informed the conduct of the study. RESULTS: Prostate cancer specialist nurses characterised the prostate cancer survivorship experience of men as under-resourced, disjointed and distressing. In all, 11 survivorship priorities for men and three for partners were identified within five broad areas: capacity building; care coordination; physical and psychosocial care; community awareness and early detection; and palliative care. However, feasibility for individual items was frequently described as low. CONCLUSION: Internationally, prostate cancer survivorship care for men and their partners requires urgent action to meet future need and address gaps in capacity and care coordination. Low feasibility of survivorship priorities may reflect translational challenges related to capacity. Prostate cancer survivorship care guidelines connected to practice priorities are urgently needed. RELEVANCE TO CLINICAL PRACTICE: These findings address key gaps in the evidence for developing national nurse-led prostate cancer survivorship priorities. These priorities can be used to inform survivorship guidelines including nursing care for men with prostate cancer and their partners.

Comparison of Aggregated N-of-1 Trials with Parallel and Crossover Randomized Controlled Trials Using Simulation Studies.

Background: N-of-1 trials offer an innovative approach to delivering personalized clinical care together with population-level research. While increasingly used, these methods have raised some statistical concerns in the healthcare community. Methods: We discuss concerns of selection bias, carryover effects from treatment, and trial data analysis conceptually, then rigorously evaluate concerns of effect sizes, power, and sample size through simulation study. Four variance structures for patient heterogeneity and model error are considered in a series of 5000 simulated trials with three cycles, which compare N-of-1 trials to parallel randomized controlled trials (RCTs) and crossover trials. Results: N-of-1 trials outperformed both traditional parallel RCTs and crossover designs when trial designs were simulated in terms of power and required sample size to obtain a given power. N-of-1 designs resulted in a higher type-I error probability than parallel RCT and cross over designs when moderate-to-strong carryover or washout effects were not considered or in the presence of modeled selection bias. However, N-of-1 designs allowed better estimation of patient-level random effects. These results reinforce the need to account for these factors when planning N-of-1 trials. Conclusion: N-of-1 trial designs offer a rigorous method for advancing personalized medicine and healthcare with the potential to minimize costs and resources. Interventions can be tested with adequate power with far fewer patients than traditional RCT and crossover designs. Operating characteristics compare favorably to both traditional RCT and crossover designs.

A feasibility study with embedded pilot randomised controlled trial and process evaluation of electronic cigarettes for smoking cessation in patients with periodontitis.

BACKGROUND: Tobacco smoking is a major risk factor for several oral diseases, including periodontitis, and electronic cigarettes (e-cigarettes) are increasingly being used for smoking cessation. This study aimed to assess the viability of delivering and evaluating an e-cigarette intervention for smoking cessation within the dental setting, prior to a definitive study. METHODS: A feasibility study, comprising a pilot randomised controlled trial and qualitative process evaluation, was conducted over 22 months in the Newcastle upon Tyne Hospitals NHS Dental Clinical Research Facility, UK. The pilot trial comprised a two-armed, parallel group, individually randomised, controlled trial, with 1:1 allocation. Participant eligibility criteria included being a tobacco smoker, having periodontitis and not currently using an e-cigarette. All participants received standard non-surgical periodontal therapies and brief smoking cessation advice. The intervention group additionally received an e-cigarette starter kit with brief training. Proposed outcomes for a future definitive trial, in terms of smoking behaviour and periodontal/oral health, were collected over 6 months to assess data yield and quality and estimates of parameters. Analyses were descriptive, with 95% confidence intervals presented, where appropriate. RESULTS: Eighty participants were successfully recruited from a range of dental settings. Participant retention was 73% (n = 58; 95% CI 62-81%) at 6 months. The e-cigarette intervention was well received, with usage rates of 90% (n = 36; 95% CI 77-96%) at quit date. Twenty percent (n = 8; 95% CI 11-35%) of participants in the control group used an e-cigarette at some point during the study (against advice). The majority of the outcome measures were successfully collected, apart from a weekly smoking questionnaire (only 30% of participants achieved ≥ 80% completion). Reductions in expired air carbon monoxide over 6 months of 6 ppm (95% CI 1-10 ppm) and 12 ppm (95% CI 8-16 ppm) were observed in the control and intervention groups, respectively. Rates of abstinence (carbon monoxide-verified continuous abstinence for 6 months) for the two groups were 5% (n = 2; 95% CI 1-17%; control group) and 15% (n = 6; 95% CI 7-29%; intervention group). CONCLUSIONS: Data suggest that a definitive trial is feasible and that the intervention may improve smoking quit rates. Insights were gained into how best to conduct the definitive trial and estimates of parameters to inform design were obtained. TRIAL REGISTRATION: ISRCTN, ISRCTN17731903; registered 19 September 2016 http://www.isrctn.com/ISRCTN17731903.

Changes in physical activity during the retirement transition: a series of novel n-of-1 natural experiments.

BACKGROUND: Existing evidence about the impact of retirement on physical activity (PA) has primarily focused on the average change in PA level after retirement in group-based studies. It is unclear whether findings regarding the direction of PA change after retirement from group-based studies apply to individuals. This study aimed to explore changes in PA, PA determinants and their inter-relationships during the retirement transition at the individual level. METHODS: A series of n-of-1 natural experiments were conducted with seven individuals who were aged 55-76 years and approaching retirement. PA was measured by tri-axial accelerometry. Twice-daily self-report and ecological momentary assessments of evidence- and theory-based determinants of PA (e.g. sleep length/quality, happiness, tiredness, stress, time pressure, pain, intention, perceived behavioural control, priority, goal conflict and goal facilitation) were collected via a questionnaire for a period of between 3 and 7 months, which included time before and after the participant's retirement date. A personalised PA determinant was also identified by each participant and measured daily for the duration of the study. Dynamic regression models for discrete time binary data were used to analyse data for each individual participant. RESULTS: Two participants showed a statistically significant increase in the probability of engaging in PA bouts after retirement and two participants showed a significant time trend for a decrease and increase in PA bouts over time during the pre- to post-retirement period, respectively. There was no statistically significant change in PA after retirement for the remaining participants. Most of the daily questionnaire variables were significantly associated with PA for one or more participants but there were no consistent pattern of PA predictors across participants. For some participants, the relationship between questionnaire variables and PA changed from pre- to post-retirement. CONCLUSIONS: The findings from this study demonstrate the impact of retirement on individual PA trajectories. Using n-of-1 methods can provide information about unique patterns and determinants of individual behaviour over time, which has been obscured in previous research. N-of-1 methods can be used as a tool to inform personalised PA interventions for individuals within the retirement transition.

Dynamic modelling of n-of-1 data: powerful and flexible data analytics applied to individualised studies.

N-of-1 studies are based on repeated observations within an individual or unit over time and are acknowledged as an important research method for generating scientific evidence about the health or behaviour of an individual. Statistical analyses of n-of-1 data require accurate modelling of the outcome while accounting for its distribution, time-related trend and error structures (e.g., autocorrelation) as well as reporting readily usable contextualised effect sizes for decision-making. A number of statistical approaches have been documented but no consensus exists on which method is most appropriate for which type of n-of-1 design. We discuss the statistical considerations for analysing n-of-1 studies and briefly review some currently used methodologies. We describe dynamic regression modelling as a flexible and powerful approach, adaptable to different types of outcomes and capable of dealing with the different challenges inherent to n-of-1 statistical modelling. Dynamic modelling borrows ideas from longitudinal and event history methodologies which explicitly incorporate the role of time and the influence of past on future. We also present an illustrative example of the use of dynamic regression on monitoring physical activity during the retirement transition. Dynamic modelling has the potential to expand researchers' access to robust and user-friendly statistical methods for individualised studies.

The state of the art and future opportunities for using longitudinal n-of-1 methods in health behaviour research: a systematic literature overview.

n-of-1 studies test hypotheses within individuals based on repeated measurement of variables within the individual over time. Intra-individual effects may differ from those found in between-participant studies. Using examples from a systematic review of n-of-1 studies in health behaviour research, this article provides a state of the art overview of the use of n-of-1 methods, organised according to key methodological considerations related to n-of-1 design and analysis, and describes future challenges and opportunities. A comprehensive search strategy (PROSPERO:CRD42014007258) was used to identify articles published between 2000 and 2016, reporting observational or interventional n-of-1 studies with health behaviour outcomes. Thirty-nine articles were identified which reported on n-of-1 observational designs and a range of n-of-1 interventional designs, including AB, ABA, ABABA, alternating treatments, n-of-1 randomised controlled trial, multiple baseline and changing criterion designs. Behaviours measured included treatment adherence, physical activity, drug/alcohol use, sleep, smoking and eating behaviour. Descriptive, visual or statistical analyses were used. We identify scope and opportunities for using n-of-1 methods to answer key questions in health behaviour research. n-of-1 methods provide the tools needed to help advance theoretical knowledge and personalise/tailor health behaviour interventions to individuals.

Changes in physical activity during the retirement transition: a theory-based, qualitative interview study.

BACKGROUND: There are considerable inter-individual differences in the direction and degree of change in physical activity (PA) levels during the retirement transition. There is currently a limited theoretical understanding of how these differences can be explained. This study aimed to explore and compare perceptions about how theory-based factors influence PA change during the transition from employment to retirement among individuals approaching retirement and recently retired. METHODS: Theory-based, one-to-one, semi-structured interviews were conducted with a purposive sample of 28 adults (15 retired) within 24 months of retirement. Participants were sampled to reflect a diverse range of socio-economic and occupational backgrounds. The interview was based on the 12 domains within the Theory Domain Framework and designed to elicit anticipated or experienced retirement-related changes in PA behaviour and perceived determinants. Interview transcripts were analysed using Framework analysis to explore intra- and inter-individual perceptions of how PA changes after retirement and the factors which may influence this change. RESULTS: The majority of participants perceived retirement to be related to an increase in PA levels. Four themes emerged from the data regarding factors perceived to influence changes in PA behaviour after retirement: (1) resources for PA; (2) structure of daily life in retirement; (3) opportunities for PA; and (4) transitional PA phases after retirement. Retirement is associated with a number of inter-related changes and opportunities which can have a positive or negative impact on PA behaviour. The influence of these factors does not appear to be static and may change over time. A number of different transitional phases may be experienced after leaving work and each phase may have a differential impact on PA behaviour. CONCLUSIONS: The findings of this qualitative study contribute to the theoretical understanding of PA change during the retirement transition. Each post-retirement PA trajectory is highly individual and personalised intervention approaches to increase PA during the retirement transition may be most successful. Future research should focus on the maintenance of PA change during the retirement transition and should develop and evaluate interventions to promote and maintain PA during retirement.