Review articlePhysical activity and suicidal ideation: A systematic review and meta-analysis
Introduction
Suicide, defined as deaths caused by intentional, self-inflicted poisoning or injury, represents a global public health problem (WHO, 1993). It is the 13th leading cause of years of life lost worldwide (Wang et al., 2013). Globally, there are an estimated 11.4 suicides per 100,000 people, resulting in 804,000 suicide deaths worldwide (Turecki and Brent, 2016). Non-fatal suicidal behaviors occur at significantly higher frequencies than suicides (Turecki and Brent, 2016). International comparisons based on the WHO World Mental Health Survey (2001–2007) data (n = 108,705) indicate that the average twelve-month prevalence estimates are 2.0% and 2.1% for suicidal ideation (SI), and 0.3% and 0.4% for suicide attempts in developed and developing countries, respectively (Borges et al., 2010). In developing and developed countries, those who report SI within the previous 12 months have a 15.1% and 20.2% higher 12-month prevalence of suicide, respectively (Borges et al., 2010). Those who attempt suicide have a 12-month suicide risk and repeated suicide attempt risk of about 1.6% and 16.3%, respectively, with a 5-year risk of suicide of 3.9% (Carroll et al., 2014).
As there is a clear relationship between SI and attempted and completed suicide (Turecki and Brent, 2016), identifying risk factors and treatments for people experiencing SI is essential in order to reduce suicide attempts and deaths. In high-income countries, middle-aged and elderly men have the highest risk and highest SI levels, with notably increased levels among those with sleep disturbances, somatic conditions (for example, epilepsy), painful comorbidities, depression, post-traumatic stress disorder and anxiety (Conwell et al., 2011, Krysinska and Lester, 2010, Nevalainen et al., 2016, Stubbs, 2016, Stubbs et al., 2016b). Adolescent suicide rates are increasing, and suicide is the second leading cause of death in those between 15 and 29 years (Turecki and Brent, 2016). The peak incidence of SI occurs during adolescence and young adulthood, with the lifetime prevalence of SI 12–33% (Brezo et al., 2007, Nock et al., 2013). Gender is also a clear risk factor with higher rates of SI among women (Nock et al., 2008).
Psychosocial interventions including dialectic and cognitive behavior therapy for those with SI have demonstrated reductions in suicide attempts (Turecki and Brent, 2016). Although these targeted psychotherapeutic interventions are vital and effective in saving the lives of many people each year, they are not widely available. Additionally, evidence for their effectiveness is predominantly derived from those at very high risk for suicide. There is also some evidence that pharmacotherapy and in particular lithium and clozapine are effective in reducing SI among adults (Zalsman et al., 2016). However, psychotropic medications may have detrimental cardio-metabolic side-effects in adults (Vancampfort et al., 2015b) and adolescents (Galling et al., 2016).
A potential approach to suicide prevention that has not been closely examined, but which holds promise in terms of widespread dissemination without major side-effects, is physical activity. Physical activity can be defined as any activity that involves bodily movement produced by skeletal muscles and that requires energy expenditure (Caspersen et al., 1985). There is robust evidence that physical activity has been shown to reduce several important risk factors for suicide including depressive symptoms (Schuch et al., 2016), anxiety symptoms (Stubbs et al., 2017), symptoms of psychosis (Firth et al., 2015, Rosenbaum et al., 2014), post-traumatic stress symptoms (Rosenbaum et al., 2015), disturbed sleep (Kredlow et al., 2015), alcohol abuse (Hallgren et al., 2017) and chronic somatic conditions (Pedersen and Saltin, 2015). Physical activity can be delivered at low cost and, unlike traditional mental health interventions, it is generally non-stigmatizing. However, to the best of our knowledge no systematic review and meta-analysis has examined the relationship between physical activity and SI, or the effect of physical activity interventions on SI levels. As suicide risks differ across the lifespan and between men and women, this review will assess associations between physical activity and SI in (pre-)adolescents, adults, and older adults and both genders separately.
Given the aforementioned, this systematic review and meta-analysis set out to: (a) explore cross-sectional and prospective associations between physical activity and SI levels, and (b) investigate the effect of physical activity interventions on SI.
Section snippets
Material and methods
This systematic review was conducted in accordance with the MOOSE guidelines (Stroup et al., 2000) and in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standard (Moher et al., 2009).
Study selection, characteristics and included participants
The electronic database searches identified 2233 articles which were considered at the title and abstract level. After excluding irrelevant papers and duplicates, forty-seven full texts were reviewed and 18 were excluded with reasons (see Fig. 1 and eTable 1), with 29 unique studies meeting the eligibility criteria. The final sample comprised 720,652 unique persons with a median sample size of 12,081. There were 25 cross-sectional studies (Adams et al., 2007, An et al., 2015, Arat and Wong, 2017
General findings
To the best of our knowledge, the current review is the first to explore associations between physical activity and SI, and outcomes of physical activity interventions on SI. Our study demonstrated that meeting physical activity guidelines conferred a significant protective effect on SI (OR = 0.91, 95%CI = 0.51–0.99, P = 0.03; N studies = 3, n people = 122,395), while not meeting guidelines was associated with increased SI-levels (OR = 1.16, 95%CI = 1.09–1.24, P < 0.001; N = 4, n = 78,860).
Acknowledgments
None.
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