200 Higher bone mineral density in prediabetes, diabetes and with increasing HbA1c in older Irish adults: results from the TUDA study

Abstract

Abstract Background Patients with type II diabetes have higher Bone Mineral Density (BMD) but paradoxically have an increased fracture risk. However, less is known about the relationship between prediabetes and BMD or fracture risk. We aimed to evaluate the relationship between pre-diabetes, diabetes, HbA1c and BMD in older Irish adults. Methods Study participants were from a large cross-sectional study of adults aged >60 years; Trinity Ulster University Department of Agriculture (TUDA) study. Patients on treatment for osteoporosis, current or previous long-term glucocorticoids, aromatase inhibitors or androgen deprivation therapy were excluded. Diabetes was defined by self-report, use of diabetic medications or HBA1c ≥6.5% and after excluding same, prediabetes was defined as a HbA1c of 5.7–6.4%[1]. BMD was measured by DXA at the total hip and lumbar spine. The relationship between prediabetes, diabetes, HbA1c and BMD was explored in regression models. Results There were 2,127 participants and mean age was 70.0 ± 6.5 with 57.9% female. 17.7% had diabetes and 26% prediabetes. Compared to normoglycaemic participants, diabetics had higher BMD at the hip (p < 0.001) and spine (p = 0.007) and prediabetics higher BMD at the hip (p < 0.001) after adjusting for age, sex, body mass index, serum vitamin D, eGFR, smoking, alcohol intake and timed up and go. In multivariate analysis, increasing HbA1c in non-diabetics was also associated with greater BMD at the hip (p = 0.001) but not the spine. Conclusion This study demonstrates that BMD is increased in older adults with both diabetes and prediabetes and with increasing HbA1c in non-diabetics. Despite this, BMD is known to underestimate fracture risk in diabetics where a lower treatment threshold for starting osteoporosis medications is recommended. This might also hold true in prediabetes where altered BMD could affect material bone quality and fracture risk though studies are conflicting and more research is required.