ABSTRACT
Background: Previous research has shown patients with schizophrenia to have reduced bone mineral density (BMD) and increased fracture risk. However, less is known regarding the effects of antipsychotic treatment independent of disease state. Thus, we aimed to investigate the association between antipsychotic use and bone mineral density in a population-based sample of women.
Methods: Current antipsychotic users (n=39) and non-users (n=750) aged from 23 to 95 years were drawn from the Geelong Osteoporosis Study (GOS). BMD (g/cm2) was measured at the spine, hip and total body using dual-energy absorptiometry (DXA). Anthropometry and socio-economic status (SES) were determined, and information on medication use, and lifestyle was obtained via questionnaire. Regression analysis was used to test associations after adjusting for potential covariates.
Results: Antipsychotic users were less active and more likely to use antidepressants and hormone therapy and drink less alcohol; otherwise the groups were similar in regard to age, height, weight, SES, smoking status and use of thyroid and bone active medications. Age was an effect modifier in the relationship between antipsychotic use and BMD. Among women aged <50 years (n=319), age?-adjusted mean BMD for antipsychotic users was 6.0% lower at the spine [1.305 (1.173-1.437) vs. 1.388 (1.283- 1.494) g/cm2, p=0.047] and 6.1% lower at the femoral neck [0.937 (0.876-0.998) vs. 0.998 (0.980- 1.016) g/cm2, p=0.058] compared to non-users. Associations persisted following further adjustment for alcohol consumption, smoking, SES and medications known to affect bone. There was no relationship detected at the total body and for ages ≥50 years.
Conclusion: These population-based data suggest antipsychotic use is associated with lower BMD in younger but not older women. Further research is required to investigate the underlying mechanisms involved.