Duration of the untreated period affects bone mineral density in psychiatric patients requiring long-term hospitalization: A cross-sectional study

Abstract

Aim: Osteoporosis and bone fractures occur often on psychiatric wards. Although recent studies showed that bone mineral density (BMD) decreases in psychiatric patients, many risk factors remain unknown. This study aimed to explore the risk factors for decreased BMD in long-term psychiatric inpatients in a closed ward. Methods: A cross-sectional study of psychiatric inpatients hospitalized for over 20 weeks was conducted. Patients were divided into three groups according to BMD: normal, osteopenia, and osteoporosis. Psychiatric symptoms were assessed using the Brief Psychiatric Rating Scale (BPRS). The relevant history of psychiatric diseases was collected, and biomarkers related to osteoporosis were measured. Univariable and multivariable ordinal logistic regression analyses were performed to identify variables significantly associated with BMD category. Additional analyses evaluated the associations between an identified clinical variable and biomarkers and psychiatric symptoms that may be related to osteoporosis. Results: Seventy-one patients (28 normal BMD, 17 osteopenia, and 26 osteoporosis) participated in the study. The multivariable ordinal logistic analysis showed that the duration of untreated psychosis (DUP) was a risk factor (odds ratio = 0.77, 95% confidence interval: 0.63–0.91, p = 0.006), adjusting for the major confounders of sex and age. Additional analysis showed significant differences in BPRS, BPRS Negative Symptom score, and the Cu/Zn ratio between the short-DUP group (DUP ≤ 1 year) and the long-DUP group (DUP > 1 year). Conclusion: The DUP may affect BMD in long-term psychiatric inpatients, presumably partly through increased severity of negative symptoms and micronutrient abnormalities. Shortening the untreated period might reduce the risk of osteoporosis.