Evaluation of hemorheological parameters as biomarkers of calcium metabolism and insulin resistance in postmenopausal women.

Background: Calcium, vitamin D and insulin resistance are linked to osteoporosis and cardiovascular disease in menopause.

Objective: Determine if hemorheological parameters related to blood viscosity in microcirculation are linked to calcium metabolism and insulin resistance in menopause.

Methods: 25-Hydroxyvitamin D (25(OH)D)), 1, 25-dihydroxyvitamin D3 (1, 25(OH)2D), parathyroid hormone, ionized calcium, glucose, insulin and hemoglobin A1c were measured in blood from 43 volunteers. Red blood cells (RBC) aggregation, RBC deformability and whole blood viscosity were also performed.

Results: 25(OH)D showed a positive correlation with RBC deformability 0.60 Pa. Subjects with 25(OH)D≤29.00 ng/mL had lower RBC deformability 0.60 Pa, and higher RBC aggregation and higher HOMA-IR. Ionized calcium showed a negative correlation with RBC aggregation. Subjects with ionized calcium ≤1.24 mmol/L showed higher RBC aggregation. There was a positive correlation between HOMA-IR and RBC aggregation and HOMA-IR showed a negative correlation with RBC deformability 0.30 Pa. Subjects with HOMA-IR <1.80 showed lower RBC aggregation and higher RBC deformability at 0.30 Pa, 0.60 Pa, 1.20 Pa, 3.0 Pa and 6.0 Pa.

Conclusion: Low 25(OH)D, low ionized calcium and high HOMA-IR are related to impaired hemorheology in menopause. RBC aggregation and deformability can be used as biomarkers of calcium metabolism and insulin resistance in menopause.