The prevalence of type 2 diabetes (T2DM) is increasing globally alongside an increasing prevalence of osteoporosis and fracture. T2DM and its effect on fractures or resultant mortality is unclear. This study examined the effect of T2DM on fracture and its impact on fracture-related mortality in the Canadian Multicentre Osteoporosis study (CaMos).
7691 community-dwelling adults aged 50+ years from 9 Canadian centres had data collected at baseline, 3(ages 40-60yrs), 5, 10 and 16 (women 60-85yrs; men 60-75yrs) years included co-morbidities, lifestyle factors, medications and bone mineral density(BMD). T2DM status was further refined with age of onset and medication use. Fracture and mortality data were assessed by self-report with subsequent verification and yearly phone calls to participants or next of kin. Cox proportional hazards were used for time-dependent analysis with fracture and mortality as outcomes in separate models for women and men, making adjustment for known risk factors.
Results: 25%(1357/5485) of women(173 with T2DM-25%) and 14%(295/2138) of men (45 with T2DM-12.5%) suffered a fracture, of whom 19.7%(1081) women (25% with T2DM) and 27.4%(585) men(31.5% with T2DM) died. The fracture rates in those with and without T2DM were not different (p= 0.39 women, 0.77 men). However, total hip BMD was higher in people with T2DM compared to those without in both men (0.99 vs 1.03 g/cm2, p = 0.01) and women (0.83 vs 0.89 g/cm2, p <0.001). Mortality was highest with both T2DM and fracture (HR 2.08[1.48-2.91] women; 2.39[1.50-3.81] men), followed by either T2DM (HR 1.59 [1.30-1.93] women; 1.51 [1.19-1.90] men) or fracture (HR 1.57[1.34-1.84] women; 1.50[1.15-1.95] men) when compared to people with neither.
Conclusion: People with T2DM have similar fracture rate to those without in spite of higher BMD. Mortality after a fracture is similar to that with T2DM alone and their combined mortality is higher than either alone.