Objective Osteoporosis has been reported to increase the risk of mortality. However, these reports did not evaluate the effects of co-mobidities and the severity of osteoporosis on mortality. The aim of our study was to determine whether or not major osteoporotic fractures contribute to the increased mortality risk in Japanese women.
Method We conducted a prospective observational study. Risk factors contributing to mortality were assessed by Cox's proportional hazard model.
Subjects A total of 1,429 ambulatory postmenopausal female volunteers aged over 50 years old were enrolled in the study. Information was obtained from the subjects on baseline biochemical indices, bone mineral density (BMD), prevalent fractures, and co-morbidities. Mortality was assessed and confirmed by the certificates or hospital records. The subjects were classified into three categories in accordance with or without osteoporosis. The osteoporotic group was further categorized by the basis of the presence or absence of major osteoporotic fractures.
Results Mean age and SD of the participants were 66.5±9.3 (50-90) years old. The participants were followed for a total of 4.5±3.5 years (mean ± SD) and a total of 141 participants (9.9%) died during the observation. In addition to the traditional risks for mortality, such as age (Hazard ratio, 2.817, 95% CI, 2.237-3.560, p<0.0001), BMI (HR 0.504, 0.304-0.824, p=0.0061), prevalent malignancies (HR 2.885, 1.929-4.214, p<0.0001), dementia (HR 1.602, 1.027-2.450, p=0.038) and cardio-vascular disease (HR 1.878, 1.228-2.787, p=0.0043), the serum level of creatinine (HR 2.451, 1.107-5.284, p=0.027) and severity of osteoporosis (HR 1.390, 1.129-1.719, P=0.0018) were found to be significant independent risk factors for all-cause mortality.
Conclusion These results emphasize the importance of osteoporotic fracture in terms of survival.
2011 by The Japanese Society of Internal Medicine