Diabetes and fracture risk in older U.S. adults.

OBJECTIVE: We examined the diabetes-fracture relationship by race/ethnicity, including the link between pre-diabetes and fracture.

RESEARCH DESIGN AND METHODS: We used Medicare- and mortality-linked data for respondents aged 65years and older from the third National Health and Nutrition Examination Survey (NHANES III) and NHANES 1999-2004 for three race/ethnic groups: non-Hispanic whites (NHW), non-Hispanic blacks (NHB), and Mexican Americans (MA). Diabetes was defined as diagnosed diabetes (self-reported) and diabetes status: diagnosed and undiagnosed diabetes (positive diagnosis or hemoglobin A1c (A1C)≥6.5%); pre-diabetes (no diagnosis and A1C between 5.7% and 6.4%); and no diabetes (no diagnosis and A1C<5.7%). Non-skull fractures (n=750) were defined using published algorithms. Hazards ratios (HRs) were calculated using Cox proportional hazards models.

RESULTS: The diabetes-fracture relationship differed significantly by race/ethnicity (pinteraction<0.05). Compared to those without diagnosed diabetes, the HRs for those with diagnosed diabetes were 2.37 (95% CI 1.49-3.75), 1.87 (95% CI 1.02-3.40), and 1.22 (95% CI 0.93-1.61) for MA, NHB, and NHW, respectively, after adjusting for significant confounders. HRs for diagnosed and undiagnosed diabetes were similar to those for diagnosed diabetes alone. Pre-diabetes was not significantly related to fracture risk, however. Compared to those without diabetes, adjusted HRs for those with pre-diabetes were 1.42 (95% CI 0.72-2.81), and 1.20 (95% CI 0.96-1.51) for MA and NHW, respectively. There were insufficient fracture cases to examine detailed diabetes status in NHB.

CONCLUSIONS: The diabetes-fracture relationship was stronger in MA and NHB. Pre-diabetes was not significantly associated with higher fracture risk, however.