Association of type 2 diabetes and an inflammatory marker with incident bone fracture among a Japanese cohort

AIMS/INTRODUCTION There are various causes of incident bone fracture. Not only aging, low bone mineral density and history of previous fracture, but also diabetes mellitus and inflammation are regarded as risk factors for fracture. The purpose of the present study was to verify the association of glycemic control or one inflammatory marker with incident fracture in a large-scale Japanese cohort. MATERIALS AND METHODS The present study was carried out at the Hiroshima Atomic Bomb Casualty Council and included 6,556 participants (2,785 men and 3,771 women, aged 55-87 years) who underwent annual health examinations and were followed for 7.4 years. Information about incident fractures was collected at interviews. Participants were classified into three groups: normal, borderline and diabetes mellitus according to glycohemoglobin levels (treated diabetes patients were included in the diabetes mellitus group). Furthermore, participants were classified into four additional groups by glycemic control (diabetes mellitus or non-diabetes mellitus) and C-reactive protein (CRP) levels (low or high). Hazard ratios (HRs) of diabetes mellitus, CRP and their combined risk of incident fracture were evaluated. RESULTS After adjusting for age, bone mineral density and previous fracture, CRP was associated with increased fracture risk (in men HR 1.04, 95% confidence interval [CI]: 1.003-1.06; in women HR 1.07, 95% CI: 1.03-1.13), and diabetes mellitus predicted fracture risk in men (HR 1.31, 95% CI: 1.02-1.51). Fracture risk was significantly higher among the diabetes mellitus with high CRP group compared with the non-diabetes mellitus with low CRP group (in men HR 1.47, 95% CI: 1.02-1.98; in women HR 1.41, 95% CI: 1.04-1.92). CONCLUSIONS Among a Japanese cohort, CRP measurements were helpful to detect high fracture risk in patients with type 2 diabetes mellitus.