Objective: Little is known about whether diabetic dyslipidaemia contributes to increased bone fragility in patients with diabetes. This study aimed to explore the potential effects of dyslipidaemia on vitamin D and bone metabolism in elderly subjects with type 2 diabetes (T2D).
Methods: A total of 1479 male patients and 1356 female patients 50 years or older with T2D were included in Shanghai, China. Lipid profiles, 25-hydroxyvitamin D (25(OH)D), serum procollagen type I N-terminal propeptide (P1NP), β-C-terminal telopeptide (β-CTX) and other parameters were measured. Principal component regression (PCR) and mediation analysis were used to estimate the associations of lipid profile, 25(OH)D and bone turnover levels.
Results: Female patients presented with higher blood lipids, lower 25(OH)D, and higher P1NP and β-CTX levels than male patients with T2D. TC was associated with P1NP in males and females (β=0.056, P < 0.05; β=0.095, P < 0.01, respectively), and 25(OH)D fully mediated the associations in males and mediated approximately 17.89% of the effects in females. LDL-C was associated with P1NP in males and females (β=0.072 and 0.105 respectively, all P < 0.01), and 25(OH)D mediated the relationships approximately 20.83% in males and 14.29% in females. TG was negatively associated with P1NP (in males, β= − 0.063, P < 0.05; in females, β= − 0.100, P < 0.01) and β-CTX (in males, β= − 0.108; in females, β= − 0.128, all P < 0.01) independent of 25(OH)D, while HDL-C was not associated with P1NP or β-CTX in diabetic patients.
Conclusion: Hypercholesterolemia and hypertriglyceridaemia might affect bone metabolism by distinguishing pathways in diabetes patients. Ameliorating lipid control in elderly diabetes patients, especially female patients, will benefit both vitamin D and bone metabolism.
Plain Language Summary: Diabetic dyslipidaemia may be one of the factors involved in increased bone fragility in diabetes. Currently, there have been few studies regarding the effects of dyslipidaemia on vitamin D and bone metabolism in diabetes. We aimed to explore the potential effects of dyslipidaemia on vitamin D and bone metabolism in elderly subjects with T2D. Thus, we conducted a cross-sectional study of 2835 adult T2D patients 50 years or older in Shanghai, China. Our study revealed that high levels of cholesterol and triglycerides might have detrimental effects on vitamin D metabolism and bone turnover by distinguishing pathways in elderly patients with T2D, and discrepancies exist between male and female patients. Ameliorating lipid control in elderly diabetes patients, especially female patients, will benefit both vitamin D and bone metabolism.
Keywords: type 2 diabetes, elderly patients, lipid profile, vitamin D, bone turnover markers