Little is know about fracture risks in mentally ill adults. We aimed to estimate risks of fracture at any site, and at sites linked with osteoporosis, in this group versus the general population.

We created a population-based cohort using the UK General Practice Research Database (GPRD), with follow-up during 1987-2005. We investigated age and sex-specific fracture risks in psychotic illness (N=4283), non-psychotic affective disorder (N=95,228), and any other psychiatric conditions (N=49,439). Controls were all subjects with no psychiatric code (N=182,851) against which age-stratified relative risks were estimated: 18-44, 45-74, 75+ years. Outcomes were incident cases of fracture at any site, the hip and distal radius.

Among all mentally ill women, the highest relative risks of fracture at any site were in the youngest age group, whereas the strongest effects in men were with older age. The highest raised risk of any fracture occurred in younger women with psychotic disorders (RR 2.5, CI 1.5-4.3). Hip fracture rates were raised in elderly women and men with psychiatric illness, and were especially high in women (RR 5.1, CI 2.7-9.6) and men (RR 6.4, CI 2.6-16.1) with psychotic disorders at 45-74 years. Data were sparse for estimating relative risk of distal radius fracture, although risk was modestly (but significantly) higher among women with any mental illness in each age group.

These elevated risks are likely to be explained by a range of mechanisms. Further research is needed to elucidate these and to inform the development of targeted interventions.