Background: Chronic hyperglycemia has been previously reported to affect bone metabolism. However, this association may also be affected by other factors surrounding the hyperglycemic state, including physiologic complications of diabetes mellitus and its treatments. This study aims to assess to what extent hyperglycemia itself affects bone metabolism, using HbA1c as an indicator for chronic hyperglycemia.

Methods: We retrospectively examined data on all patients older than 20 years old who visited St. Luke’s Hospital for annual health checkup from April 2004 to March 2017. T scores were measured by forearm Dual-energy X-ray absorptiometry (DXA). Longitudinal analysis was used for statistical analyses, using multi-level mixed effect modeling treating T scores as a time-dependent variable to calculate beta coefficients, based on a T score range of HbA1c 5.5- 6.4. Data were adjusted for age, BMI, alcohol consumption, smoking, and exercise.

Results: 129,295 patients (mean age, 45.3 ±12.5 years; mean BMI, 22.3 ±3.39 kg/m2; male, 49.1%) were included over a median follow-up time of 744 days. Mean T score value was 99.1±12.3%. In longitudinal regression for men, T scores of HbA1c <=5.4 and HbA1c 6.5-8.4 were significantly low (βcoefficient -0.58- -0.14, P<0.05). In women under 50 years old, T scores in HbA1c range of 4.5-5.4 were significantly high (βcoefficient 0.19, P<0.05); T scores in a HbA1c range of 6.5-7.4 were significantly low (βcoefficient -0.60, P<0.05). In women >= 50 years, T scores in a HbA1c range of 4.5-5.4 were significantly high (βcoefficient 0.15, P<0.05), while T scores of HbA1c >=6.5 were significantly low (βcoefficient -1.80- -0.57, P<0.05).

Conclusion: Both men and women tend to have low bone mineral density at HbA1c values >= 6.5. Especially in women older than 50 years, bone mineral density significantly decreases as the value of HbA1c increases.


S. Hayashi: None. G. Deshpande: None. H. Noto: None.

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