Meta-analysis of physical activity and effects of social function and quality of life on the physical activity in patients with schizophrenia.

Schizophrenia patients have increased mortality and morbidity, mainly due to premature cardiovascular disease resulting from decreased physical activity (PA). However, which PA intensity is impaired in the patients and how factors such as social function and quality of life (QoL) are related to decreased PA is unknown. To assess PA, social function and QoL, the International Physical Activity Questionnaire (IPAQ), Social Functioning Scale (SFS) and Schizophrenia Quality of Life Scale (SQLS), respectively, were used in 109 schizophrenia patients and 69 healthy subjects. A meta-analysis comparing PA intensities (vigorous, moderate and light) assessed by the single PA measurement between schizophrenia patients and healthy subjects after including our case-control sample was performed. Furthermore, the effects of social function and QoL on each level of PA intensity were investigated in patients and controls. The meta-analysis in 212 schizophrenia patients and 132 healthy subjects revealed that patients showed lower total PA, particularly vigorous PA, than controls (I2  = 0, Hedges' g = - 0.41, P = 2.80 × 10-4 ). The decreased total PA was correlated with impaired total SFS scores (β = 0.24, P = 2.86 × 10-3 ), withdrawal (β = 0.23, P = 3.74 × 10-3 ) and recreation (β = 0.23, P = 3.49 × 10-3 ) without significant heterogeneity between patients and controls. In contrast, the decreased total PA was affected by low independence-performance (β = 0.22, P = 0.034), employment/occupation (β = 0.27, P = 8.74 × 10-3 ), psychosocial (β = - 0.24, P = 0.021) and motivation/energy (β = - 0.26, P = 0.013), but only in patients. Similar findings were obtained for vigorous PA but not moderate or light PA. Our findings suggest that the impaired vigorous PA in schizophrenia patients may be mediated by schizophrenia-specific factors of social functioning and QoL. Understanding these factors has important implications for increasing PA participation in schizophrenia patients.