Risk of low bone mineral density associated with psychotropic medications and mental disorders in postmenopausal women.

Background: Independent reports suggest that various psychotropic medications and psychiatric disorders are associated with changes in bone mineral density (BMD). The objective of this study was to clarify the independent effects of a range of mental illnesses and psychotropic medications on BMD among postmenopausal women.

Methods: Women 50 years or older with baseline BMD measured by dual-energy x-ray absorptiometry were identified in a database containing all clinical dual-energy x-ray absorptiometry test results for the Province of Manitoba, Canada. Records were linked with population-based administrative health databases to provide detailed information on sociodemographic factors, mental and physical health diagnoses, and prescription medication usage. Osteoporotic cases (n = 6820) were matched on age, sex, and ethnicity to 3 control subjects with normal BMD (n = 20,247). Multivariable conditional logistic regression compared cases and control subjects on diagnosed mental illnesses and use of psychotropic medications.

Results: Selective serotonin reuptake inhibitors (adjusted odds ratios, 1.46; 95% confidence interval [CI], 1.25-1.69), atypical antipsychotics (AOR, 1.55; 95% CI, 1.06-2.28), and benzodiazepines (AOR, 1.17; 95% CI, 1.06-1.29) were associated with higher risk of osteoporosis. Tricyclic antidepressants were associated with lower odds of osteoporosis (AOR, 0.57; 95% CI, 0.49-0.65). These drug effects were independent of mental illness diagnoses including depression (AOR, 0.86; 95% CI, 0.75-0.98) and schizophrenia (AOR, 1.98; 95% CI, 1.04-3.77).

Conclusions: Some psychotropic medications are associated with an increased risk of osteoporotic BMD, whereas tricyclic antidepressants may be protective against osteoporosis, and these effects are independent of mental illness diagnoses. Clinicians should consider these effects when prescribing psychotropic medications in postmenopausal women.