How much physical activity do people with schizophrenia engage in? A systematic review, comparative meta-analysis and meta-regression
Introduction
People with schizophrenia experience a premature mortality gap of between 10 and 20 years from the general population (Walker et al., 2015). There is an abundance of literature demonstrating that people with schizophrenia experience high levels of metabolic syndrome (Mitchell et al., 2013, Vancampfort et al., 2015d), type two diabetes (Stubbs et al., 2015b) and cardiovascular disease (Gardner-Sood et al., 2015), which collectively account for over 70% of the premature mortality in this group (Lawrence et al., 2013).
There is promising evidence that physical activity (PA) interventions can improve cardio-metabolic outcomes and improve mental health symptoms in people with schizophrenia (Firth et al., 2015, Rosenbaum et al., 2014). Even in the absence of a change in weight status, PA can result in improvements in cardiorespiratory fitness (Vancampfort et al., 2015c), which is a better predictor of mortality than BMI in the general population (Barry et al., 2014). There is also emerging evidence that PA can improve cognition in people with schizophrenia (Kimhy et al., 2016). However, people with psychotic disorders are highly sedentary (Stubbs et al., 2015a, Stubbs et al., 2016) and experience a range of barriers to PA such as negative symptoms, pain and the side-effects of medication (Soundy et al., 2014a, Vancampfort et al., 2011, Vancampfort et al., 2012). Consequently, it might be hypothesized that many people with schizophrenia do not meet recommended PA guidelines such as accruing 150 min of moderate-vigorous PA per week (Vancampfort, 2012). It remains unclear exactly how much PA people with schizophrenia engage in, and at what intensity (i.e. light, moderate and vigorous). Moreover, the moderators of PA participation are not fully elucidated.
Given that physical activity is a modifiable risk factor for cardiovascular disease and can simultaneously improve symptoms, understanding physical activity levels and predictors among people with schizophrenia is of high clinical significance. To our knowledge, only one preliminary review has considered PA levels (Soundy et al., 2013) in people with schizophrenia. The authors (Soundy et al., 2013) focused only on outpatients and found that across three studies, people with schizophrenia engage in less light, moderate and vigorous physical activities compared to controls (p < 0.01). Since this review was published, there has been a rapid increase in the number of published papers on PA and schizophrenia, however a number of pertinent questions remain unanswered. For instance, it remains unclear how much time people with schizophrenia engage in each category of PA (light, moderate and vigorous) and which factors (e.g. negative symptoms, depressive symptoms, cognitive symptoms, mean age) influence PA. Understanding this has important implications for the successful delivery of interventions aiming to increase PA participation in practice. Moreover, some studies have utilized self-report questionnaires (SRQ) to measure PA and others have used objective measures such as accelerometers (the gold standard; (Soundy et al., 2013, Soundy et al., 2014b)). There are concerns that SRQ overestimate PA and research is required to investigate if SRQ report different levels of physical activity compared to objective measurements (Soundy et al., 2014b). Finally, it remains unclear if people with schizophrenia are less physically active than controls and exactly what this difference (if any) is.
Given the aforementioned, we set out to conduct a systematic review with the following aims 1) establish the mean time of light, moderate and vigorous PA in people with schizophrenia per day. 2) Investigate differences in PA between SRQ and objective measures. 3) Investigate moderators of each category of PA in meta-regression analyses. 4) Investigate differences in PA in people with schizophrenia versus controls.
Section snippets
Method
This systematic review adhered to the MOOSE guidelines (Stroup et al., 2000) and PRISMA statement (Moher et al., 2009).
Study selection
The initial electronic database searches identified 2745 articles (excluding duplicates) which were considered at the title and abstract level. 234 full texts were reviewed and 199 were excluded with reasons (see Fig. 1), with 35 unique studies meeting the eligibility criteria (Arbour-Nicitopoulos et al., 2014, Arbour-Nicitopoulos et al., 2010, Attux et al., 2013, Baker et al., 2014, Beebe et al., 2011, Bredin et al., 2013, Brunero and Lamont, 2010, Curtis et al., 2015, Faulkner et al., 2006,
Meta-analysis results
Full details of all meta-analysis results, including heterogeneity and publication bias data are presented in Table 2. Key results are highlighted below.
Discussion
The current study is, to our knowledge, the first to determine PA levels and predictors in people with schizophrenia. We found that people with schizophrenia spend almost 90 min participating in light intensity PA and > 45 min in moderate to vigorous PA per day. More than half of the people with schizophrenia included in the present meta-analysis met the recommended 150 min of at least moderate PA per week. Nonetheless, although these data are promising, our meta-analysis also shows that people
Conflict of interests
BS, JF, DV, AB, NV, JW, FS, TC, SR declare that they have no direct conflict of interest.
FG has received honoraria for advisory work and lectures from Roche, BMS, Lundbeck, Otsaka and Sunovion and has a family member with professional links to Lilly and GSK;
ARY has received honoraria for advisory work and lectures from Janssen, Otsuka and Sunovion.
Contributors
BS, DV and JF designed the study. BS, DV, JF conducted the searches. BS, JF, DV and AB extracted the data. BS analyzed the data and wrote the first draft. All authors provided critical revisions of manuscript and approved the final version.
Role of funding source
Funders had no role in the study at any stage.
Acknowledgements
None.
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