Bone mineral density in diabetes and impaired fasting glucose

We report that compared with normoglycaemia, post-menopausal women (non-obese and obese) with diabetes had higher lumbar spine bone mineral density (LSBMD). Femoral neck bone mineral density (FNBMD) was higher in obese post-menopausal women with diabetes. Only non-obese post-menopausal women with impaired fasting glucose (IFG) had a higher LSBMD than normoglycaemia. No other associations with IFG were observed.

Individuals with diabetes have a higher or normal bone mineral density (BMD) compared with those without diabetes. However, paradoxically, they also have a higher fracture risk. It is not clear whether those with IFG also have altered BMD. This study aimed to determine whether individuals with IFG have elevated or normal BMD.

Women (n = 858) and men (n = 970) (aged 20-80 years) from the Geelong Osteoporosis Study were included. IFG was defined as fasting plasma glucose (FPG) 5.5-6.9 mmol/L and diabetes as FPG ≥ 7.0 mmol/L, use of antihyperglycaemic medication and/or self-report. Using multivariable linear regression, the relationships between glycaemia and BMD at the femoral neck and lumbar spine were examined, and adjusted for age, body mass index (BMI), and other variables. In women, two interaction terms were identified: menopause × glycaemia and BMI × glycaemia, and thus, the analyses were stratified by menopause and obesity status (BMI cut point ≥ 30 kg/m²).

There were no associations between glycaemic status and BMD for pre-menopausal women. For non-obese post-menopausal women, there was no association between FNBMD and glycaemic status, but women with IFG or diabetes had higher LSBMD than those with normoglycaemia (7.1% and 9.7%, respectively, both p < 0.01). Obese post-menopausal women with diabetes had a higher FNBMD (8.8%, p = 0.008) and LSBMD (12.2%, p < 0.001), but those with IFG were not different from the normoglycaemia group. There were no associations detected between glycaemic status and BMD in men.

In this study, we report that compared with normoglycaemia, post-menopausal women (non-obese and obese) with diabetes had higher LSBMD. FNBMD was higher in obese post-menopausal women with diabetes. Only non-obese post-menopausal women with IFG had a higher LSBMD than normoglycaemia. No other associations with IFG were observed.