Factors influencing bone mineral density in postpartum women

Background: Osteopenia is a common condition. Therefore, identification of groups for prevention of osteoporosis and restoration of bone mineral density (BMD) remains relevant. Aim: to assess the factors contributing to development of osteopenia in puerperas. Methods: prospective cross-sectional study. We examined 112 patients aged 20-35, 3-5 days after delivery. To assess possible factors for BMD decrease, we analyzed medical history, lifestyle, nutrition, anthropometric data, obstetric and gynecological history, and pregnancy course. We also assessed serum levels of 25-hydroxycalciferol (25-OH-D) and PTH. BMD was measured by dual energy x-ray osteodensitometry. We considered Z-score from -1 to -2.5SD as osteopenia, below -2.5 SD-as osteoporosis. Results: based on Z-score values, two groups were formed: 1 (n=70) - puerperas with osteopenia, 2 (n=42) - puerperas with normal BMD. In the first group, osteopenia in the distal radius was observed in 48%, in the lumbar spine in 16% and in the proximal femur in 36%. Influence of the following possible factors in group 1 was established: BMI in 15-20 years 18 kg/m2 (p0.013), BMI 25 kg/m2 (p0.018), 25-OH-D less than 25 ng / ml (p 0.0018), calcium intake less than 800 mg/day (p0.041). Menstrual disorders (p0.052) and preeclapsia (p 0.042) affected lumbar spine BMD. In group 1, vitamin D deficiency was detected in 82% of women, 18% showed vitamin D insufficiency; in group 2, vitamin D deficiency was found in 16%, deficiency in 70%, in 14% vitamin D was normal. In women with a combination of factors such as BMI 18 kg/m; calcium intake lower than 800 mg/day, menstrual cycle disorders, vitamin D deficiency - osteopenia in the distal radius occured 11 times more often (OR=11,47059; CI 95%=[4,0326; 32,627]). Conclusion: most significant impact on BMD decrease in puerperas can be expected if patient has the following risk factors: BMI18 kg/m2; 25-OH- D25 ng/ml ; nutrition with calcium intake 800 mg per day, preeclampsia. Combination of these factors may increase the risk of osteopenia in the distal radius

The Strength of Masonry Based on the Deformation Characteristics of Its Components

The chapter presents a new approach to determining the strength of masonry reinforced with transverse meshes in mortar joints. The method consists of using the values of the modulus of elasticity and limiting deformations of the stone material, mortar for joints, and both steel and composite reinforcements. An analytical notation is proposed that integrally takes into account the characteristics of the initial materials. The results of physical tests of centrally loaded masonry pillars reinforced with steel and composite meshes are given. To test the masonry, widely used materials were used: solid brick and cement-sand mortar. The values of the bearing capacity, deformations, and internal stresses of the masonry are obtained. It is determined that the stresses in the reinforcing bars of the meshes are unevenly distributed in the horizontal plane of the mortar joint and amount to 20–37% of the design resistance of the mesh material. The strength of masonry reinforced with composite meshes is 65–75% of steel of the same cross section. It is shown that there is a good convergence of test results with the presented analytical dependence