A meta-analysis of prevalence estimates and moderators of low bone mass in people with schizophrenia

OBJECTIVE: To assess the prevalence and moderators of low bone mass, osteopenia and osteoporosis in schizophrenia patients. METHOD: Major electronic databases were searched from inception till December 2013 for studies reporting the prevalence of low bone mass (osteopenia + osteoporosis = primary outcome), osteopenia or osteoporosis in schizophrenia patients. Two independent authors completed methodological appraisal and extracted data. A random effects meta-analysis was utilized. RESULTS: Nineteen studies were included (n = 3038 with schizophrenia; 59.2% male; age 24.5-58.9 years). The overall prevalence of low bone mass was 51.7% (95% CI = 43.1-60.3%); 40.0% (CI = 34.7-45.4%) had osteopenia and 13.2% (CI = 7.8-21.6%) had osteoporosis. Compared with controls, schizophrenia patients had significantly increased risk of low bone mass (OR = 1.9, CI = 1.30-2.77, P < 0.001, n = 1872) and osteoporosis (OR = 2.86, CI = 1.27-6.42, P = 0.01, n = 1824), but not osteopenia (OR = 1.33, CI = 0.934-1.90, P = 0.1, n = 1862). In an exploratory regression analysis, older age (P = 0.004) moderated low bone mass, while older age (P < 0.0001) and male sex (P < 0.0001) moderated osteoporosis. The subgroup analyses demonstrated high heterogeneity, but low bone mass was less prevalent in North America (35.5%, CI = 26.6-45.2%) than Europe (53.6%, CI = 38.0-68.5%) and Asia (58.4%, CI = 48.4-67.7%), and in mixed in-/out-patients (32.9%, CI = 49.6-70.1%) vs. in-patients (60.3%, CI = 49.6-70.1%). CONCLUSION: Reduced bone mass (especially osteoporosis) is significantly more common in people with schizophrenia than controls.