Prevalence of osteopenia and osteoporosis and factors associated with decreased bone mineral density in elderly inpatients with psychiatric disorders in Huzhou, China

BACKGROUND: Little is known about the risks of bone fractures in elderly patients with mental disorders in China. AIM: Assess the bone mineral density (BMD) of elderly patients with mental disorders in China and identify factors that are associated with low BMD, osteopenia and osteoporosis. METHODS: One hundred and two psychiatric inpatients 60 years of age or older (including patients with schizophrenia, depression, bipolar disorder and dementia) were randomly selected from patients in the geriatric wards of the Third People's Hospital of Huzhou. Detailed demographic, clinical and biometric data were obtained and the BMD of the lumbar spine was assessed using standard dual energy X-ray absorptiometry (DXA) procedures. Based on WHO criteria, individuals with BMD 1 to 2.5 standard deviations below the mean value for healthy young adults were diagnosed as osteopenia and those with BMD values 2.5 or more standard deviations below the mean value were diagnosed as osteoporosis. RESULTS: The prevalence of osteopenia was 33.3% (95% CI, 24.4%-43.2%) and the prevalence of osteoporosis was 35.3% (26.0%-45.2%) but none of these patients – even the five patients who had had non-traumatic fractures – had ever been treated for these conditions. The prevalence of osteoporosis in females was 10-fold that in males (53% versus 5%). BMD decreased with age and increased with increasing body mass index (a reflection of nutritional status). The prevalence of osteoporosis was much higher in patients with a diagnosis of depression (58%) than in those with schizophrenia (33%), Alzheimer's disease (30%) or bipolar disorder (13%). Regression analyses found that low BMD and the combined category of osteopenia and osteoporosis were both independently associated with female gender, increasing age, decreasing body mass index, and a diagnosis of depression. BMD and osteoporosis were not significantly associated with regular use of antipsychotic medication. CONCLUSION: Osteopenia and osteoporosis are common conditions in elderly patients with mental disorders that can seriously affect their quality of life but they often go undiagnosed and untreated. Long-term prospective studies are needed to clarify the relative importance of nutritional status, activity level, medication usage, and other factors in the causal pathways that connect mental illnesses to BMD.