Study of osteogenic minerals in osteoporosis patients

Introduction

Osteoporosis is the most common metabolic bone disease in the world. It is the second leading cause of musculoskeletal morbidity in elderly. By definition it is an abnormal reduction in bone tissue mass per unit volume of anatomical bone [1] , causing skeletal weakness, although the ratio of mineral to organic elements is unchanged. It is characterized by reduction in the thickness of the cortex specially from endosteal surfaces with the medullary contents being made up of a yellow and fatty cancellous bone tissue. There is reduction in the number and size of trabeculae and in the number of osteoblast present which leads to fracture or crushes with minor trauma [2] . Diagnosing osteoporosis involves a comprehensive approach that includes clinical evaluation, bone mineral density (BMD) testing, and laboratory assessments. The gold standard for diagnosing osteoporosis is dual-energy X-ray absorptiometry (DEXA or DXA), which measures BMD at the hip and spine. A T-score of -2.5 or lower confirms osteoporosis. Additionally, laboratory tests are conducted to measure serum calcium, vitamin D, phosphorus, and parathyroid hormone (PTH) levels to rule out secondary causes of bone loss. Markers of bone turnover, such as bone-specific alkaline phosphatase (BSAP), osteocalcin, C-terminal telopeptide (CTX), and N-terminal telopeptide (NTX), are also assessed to evaluate bone formation and resorption rates. Imaging techniques like vertebral fracture assessment (VFA) using DXA or spinal X-rays may be used to detect vertebral fractures, which are common in osteoporosis but often asymptomatic. This multi-faceted diagnostic approach ensures accurate identification and management of osteoporosis [3] . Calcium along with phosphate is required for the formation of hydroxyapatite and physical strength of skeletal tissue. Bones which are in a dynamic state serve as reservoir of calcium [4] . The hormone calcitriol (Vitamin D), parathyroid and calcitonin are the major factor that regulate plasma calcium within a normal range 9-11 mg/dl. Calcium is absorbed actively in the duodenum by an active carrier mediated process using a calcium binding protein. Above the age of 16 years where there is gradual decline in the intestinal absorption of calcium which may lead to senile osteoporosis [5] .

Calcium is the fifth most common element in the body and the most prevalent cation. Hypocalcemia may be due to a reduction in either the albumin-bound calcium or the free fraction of calcium, or both. Phosphorus in the form of inorganic and organic phosphate is an important and widely distributed element in the human body. Hypophosphatemia, or phosphate depletion may be caused by a shift of phosphate from extracellular to intracellular spaces, renal phosphate wasting, decreased intestinal absorption, and loss from intracellular phosphate. 5 Objective of the study The aim and objective of this study is to estimate the levels of serum calcium, phosphorus and Vitamin D in osteoporotic patients.

Materials and Methods

This was an observational study, which was conducted under the Department of Biochemistry in association with Department of Orthopedics, Tezpur Medical College and Hospital, Tezpur after approval from the Hospital Ethics Committee and after obtaining patient's attendant's informed consent. The study was carried out in 50 patients who were diagnosed cases of osteoporosis. Cases taken in the study were amongst those who were admitted in the department of orthopaedics Tezpur medical college and hospital with different types of clinical manifestations of osteoporosis, the diagnosis of which were made on the basis of x-ray findings, clinical examinations and laboratory findings.

Inclusion criteria 1. Diagnosed cases of osteoporosis.

Exclusion criteria

Methods of evaluations

Estimation of serum calcium, phosphorus and Vitamin D was done in vitro 5600 which works on the principle of spectrophotometry. The serum was separated and centrifuged for 3 min at 3000 rpm in a clinical centrifuge machine.

Sample Analysis Estimation of Calcium on Vitros 5600 Principles of the Procedure

The Calcium test is a multilayered, analytical element coated on a polyester support. A drop of patient sample is deposited on the slide and is evenly distributed by spreading layer to the underlying layers. The bound calcium is dissociated from binding proteins, allowing the calcium to penetrate the spreading layer into the underlying reagent layer. There, the calcium forms a complex with Arsenazo Ⅲ dye, causing a shift in the absorption maxium. After incubation, the reflection density of the colored complex is measured spectrophotometrically. The amount of coloured complex formed is proportional to the calcium concentration in the sample

Estimation of Phosphorus on Vitros 5600 Principle and Procedure

The phosphorus test is a multilayered, analytical element coated on a polyester support. A drop of patient sample is deposited on the slide and is evenly distributed by spreading layer to the underlying layers.Inorganic phosphorus react with ammonium molybdate to form a phosphomolybdate complex.

Estimation of Vitamin D on Vitros 5600 Principle and Procedure

A competitive immunoassay technique is used which involves the release of the25-OH Vitamin D in the sample from the binding protein using a low pH denaturant and the subsequent competition of the free 25-OH Vitamin D with horseradish peroxidise (HRP) labelled 25 -OH Vitamin D reagent for monoclonal anti-Vitamin D bound to the wells. Unbound materials are removed by washing. The bound HRP conjugate is measured by a luminescent reaction.

Results

In our study there were 32 female subjects and 18 male subjects. The study subject's age varied within the range of 40-70 years with a mean age of 64.6±1.52 and a median age of 60 years.

Serum vitamin D

The values ranges from 10-20ng/mL with mean value 14.0±0.24 ng/mL and maximum number of subjects have serum phosphorus activity in the class interval of 10.0-12.5 ng/mL.

Discussion

Osteoporosis is a bone disease marked by a gradual loss of bone density and an elevated risk of fractures. This condition often remains symptom-free until fractures occur, which can happen even with minor injuries. In postmenopausal women over 50, these fractures account for up to 80% of all such injuries. The impact of osteoporosis is significant, posing a substantial medical burden on the elderly and placing a heavy economic strain on the healthcare system. However, early diagnosis can prevent osteoporosis-related fractures, and appropriate treatment can reduce the risk of additional fractures even after an initial one has happened. 6 The diagnosis of osteoporosis involves a multifaceted approach, combining clinical assessment, bone mineral density (BMD) testing, and laboratory evaluations to assess bone health and exclude secondary causes of bone loss. The primary diagnostic tool is dualenergy X-ray absorptiometry (DEXA or DXA), which measures BMD at critical sites like the hip and spine, with a T-score of -2.5 or lower indicating osteoporosis (Kanis et al., 2019) [7] . Laboratory tests include measurements of serum calcium, vitamin D, phosphorus, parathyroid hormone (PTH), and markers of bone turnover such as bone-specific alkaline phosphatase (BSAP), osteocalcin, Cterminal telopeptide (CTX), and N-terminal telopeptide [8] . These tests help identify potential secondary causes like hyperparathyroidism or vitamin D deficiency. Additional imaging, such as vertebral fracture assessment (VFA) using DXA or spinal X-rays, may be conducted to detect vertebral fractures, which are often asymptomatic yet common in osteoporosis patients (Eastell et al., 2016) [9] . This comprehensive diagnostic approach ensures accurate identification and effective management of osteoporosis. [10] .

In our study we found out that serum calcium levels are reduced in osteoporotic patients and the values ranges from 5.8-7.4mg/dL with mean value 6.14±0.56 mg/dL. Chen et al [11] carried out a study and found that lower serum calcium levels were common among patients with osteoporosis which is a similar finding like our study. In our study we found out the serum phosphorus levels to be in the range of 3.2-4.6 mg/dL with mean value 3.74±0.44mg/dL which is a similar finding like the study done by Tomita A. [12] . The levels of vitamin D ranges from 10-20ng/mL with mean value 14.0±0.24ng/mL which is lower than the normal range as found by study done by Voulgaridou et al. [13] .

Conclusion

From our study done on 50 patients of diagnosed osteoporosis it can be concluded that the levels of serum calcium, vitamin D levels are reduced whereas the levels of serum phosphorus remains in the normal range. These three biochemical markers can be utilized for the definitive diagnosis of osteoporosis along with bone mineral density (BMD) measurements.

References

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