Skeletal status in psychotic disorders: a population-based study.

Objective: To compare the skeletal status of subjects with primary psychotic disorders with the general population by means of bone ultrasound measurements. Schizophrenia seems to be associated with low bone mineral density through a still unclear mechanism, although information on other psychotic disorders is scarce.

Methods: In a nationally representative sample, quantitative ultrasound values of the heel, i.e., broadband ultrasound attenuation (BUA) and speed of sound, were measured from subjects with schizophrenia (n = 48), other nonaffective psychosis (n = 56), affective psychosis (n = 37), and from 6,100 population controls. The Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision lifetime psychosis diagnoses were based both on Structured Clinical Interview and case note data. Information on the most common risk factors for bone fragility was elicited through an interview, health examination, and questionnaires. In addition, serum 25-hydroxyvitamin D was measured.

Results: Women with schizophrenia and men with affective psychosis had significantly lower bone ultrasound values as compared with the age- and sex-matched population controls (Z-BUA = -0.54, p = .001 and Z-BUA = -0.37, p = .04, respectively). Significantly lower vitamin D levels were observed in subjects with schizophrenia in comparison with the general population (p = .006). Schizophrenia remained an independent determinant of poor skeletal status in women even after controlling for common risk factors for osteoporosis, vitamin D status, and antipsychotic and mood-stabilizing medication (Z-BUA = -0.54, p = .002).

Conclusions: In this population-based study, schizophrenia was found to be independently associated with poor skeletal status in women.