Association of Bone Metabolic Markers With Diabetic Retinopathy and Diabetic Macular Edema in Elderly Chinese Individuals With Type 2 Diabetes Mellitus

Abstract

Background: Diabetic retinopathy (DR) is a common and specific microvascular complication of diabetes. The association of bone metabolic markers with the risk of DR and diabetic macular edema (DME) is unclear.

Materials and methods: We investigated the association between bone turnover markers commonly examined in a clinical setting and DR and DME risk in elderly Chinese patients with type 2 diabetes mellitus (T2DM). A total of 408 patients aged 55-70 years with T2DM were included. We first performed univariable logistic regression followed by multivariable logistic regression that included variables selected using purposeful selection.

Results: Fasting blood glucose (P = 0.007) and duration of diabetes (P < 0.0001) were significantly associated with DME in multivariable logistic regression; however, the association of beta C-terminal telopeptide of collagen type I (β-CTx) with DME risk was not statistically significant (P = 0.053). Sex-stratified analysis showed that β-CTx was significantly associated with DME only in female subjects (P = 0.011).

Conclusions: β-CTx had no significant association with DR. It was significantly associated with DME in female patients with T2DM, but not in male patients with T2DM. More prospective studies with larger sample sizes are warranted to validate our findings.

Keywords: Bone metabolic markers; Diabetic macular edema; Diabetic retinopathy; β-CTx.

Figure 1. Distribution of β-CTx by sex in subjects with and without DME

P-values were obtained using multiple logistic regression controlling for fasting blood glucose, HbA1C, MAU, duration of diabetes, PINP, AZGP1, and FGF21 AZGP1, zinc-alpha-2-glycoprotein; β-CTx, beta C-terminal telopeptide of collagen type I; DME, diabetic macular edema; FGF21, fibroblast growth factor 21; HbA1C, hemoglobin A1C; MAU, microalbuminuria, PINP, procollagen type 1 N-terminal propeptide.