Association between cardiovascular autonomic neuropathy and bone mineral density in patients with type 2 diabetes mellitus

Abstract

Objective To explore the association between cardiovascular autonomic neuropathy (CAN) and bone mineral density in patients with type 2 diabetes mellitus (T2DM). Method A total of 564 patients with T2DM admitted to the Department of Endocrinology, Drum Tower Hospital of Nanjing University Medical School between Jan. 2016 and Dec. 2017 were recruited. According to the Ewing test method, 467 patients (males over 50 years and menopausal females) and 97 patients (males younger than 50 years and females in childbearing age) were divided into CAN groups and non-CAN group. Dual-energy X-ray absorptiometry was used to measure bone densities in locations of the total hip, lumbar vertebrae (L1-L4) and femoral neck. T values of corresponding site were recorded in males over 50 years and menopausal females, and Z values were recorded in males younger than 50 years and females in childbearing age. The T/Z value, age, disease duration, fasting blood glucose were compared between these two groups. Independent sample t-test and chi-square test were used for comparison, and covariance analysis and rank sum test were used for bone mineral density analysis. Pearson correlation analysis was used to investigate the correlation between bone mineral density and CAN evaluation parameters. Multiple linear regression analysis was used to investigate the influencing factors of bone density T and Z values. Result In males over 50 years and menopausal females, T-value of the total hip bone density [-0.300(-0.900, 0.500) vs 0.100(-0.400, 0.800), Z=-4.937, P<0.01], T-value of lumbar spine bone density (0.07±1.42 vs 0.51±1.37, t=3.384, F=5.602, P<0.05), and T-value of femoral neck bone density (-0.75±0.91 vs -0.40±0.92, t=4.069, F=4.484, P<0.05) were significantly lower in the CAN group than those in the non-CAN group. In males younger than 50 years and females in childbearing age, Z-value of the total hip bone density (0.20±0.81 vs 0.57±0.79, t=2.228, F=7.324, P<0.01) and femoral neck bone mineral density [-0.200(-0.600, 0.400) vs 0.250(-0.300, 1.025), Z=2.248, P<0.05] were significantly lower in the CAN group than those in the non-CAN group. After adjusting for the influencing factors such as duration of disease, age, and estradiol, CAN was still a factor influencing the T value (β=-0.256, SE=0.106, β′=-0.142, t=-2.414, P<0.05) and Z value (β=-0.554, SE=0.206, β′=-0.355, t=-2.687, P<0.05) of total hip bone density. Conclusion CAN is an important factor to decrease bone density in patients with T2DM. Key words: Diabetes mellitus, type 2; Cardiovascular autonomic neuropathy; Bone mineral density