European Journal of Cardiovascular Medicine

Osteoporosis is a significant global health burden, particularly among postmenopausal women, due to its association with progressive bone loss, compromised microarchitecture, and increased risk of fragility fractures. The cessation of ovarian estrogen production during menopause leads to an imbalance in bone remodeling, favoring resorption over formation and accelerating skeletal demineralization [1]. Among the various modifiable contributors to osteoporosis, deficiencies in calcium and Vitamin D have emerged as critical and widely prevalent risk factors.

Vitamin D is essential for calcium-phosphorus homeostasis and skeletal mineralization. It enhances intestinal absorption of calcium and phosphate, supports osteoblastic activity, and suppresses parathyroid hormone (PTH)-mediated bone resorption. Deficiency of Vitamin D disrupts this axis, impairing calcium absorption and inducing secondary hyperparathyroidism, thereby exacerbating bone loss [2,3]. Despite its physiological importance, hypovitaminosis D remains common across different populations, including in sun-rich regions, due to factors such as inadequate dietary intake, limited sun exposure, and skin pigmentation [1,4]. Postmenopausal women, particularly, are at greater risk due to age-related metabolic changes and nutritional insufficiencies.

Calcium plays a foundational role in bone strength and density. Hypocalcemia, whether resulting from dietary deficit or impaired absorption secondary to Vitamin D deficiency, further compounds the skeletal deterioration seen in osteoporosis [5]. Studies have consistently shown that calcium and Vitamin D supplementation improves biochemical parameters and reduces fracture risk in postmenopausal women [3,4,6].

Against this background, the present study aims to evaluate serum 25-hydroxyvitamin D and total calcium levels in postmenopausal women diagnosed with osteoporosis and to explore the associations between these biochemical markers and clinical characteristics such as duration of menopause and history of fractures.

Methodology

This hospital-based observational study was conducted over a four-month period from January 2024 to April 2024 at the Department of General Medicine, Government Medical College and Hospital, Bhadradri Kothagudem, Telangana, India. The study was approved by the Institutional Ethics Committee, and written informed consent was obtained from all participants prior to enrolment.

Study Population:

A total of 100 postmenopausal women diagnosed with osteoporosis were included in the study. Postmenopausal status was defined as the absence of menstruation for at least 12 consecutive months. Osteoporosis was confirmed based on clinical history and bone mineral density (BMD) reports, where available, using T-scores ≤ –2.5 as per WHO criteria.

Inclusion Criteria:

Women aged ≥50 years.

Postmenopausal for at least one year.

Clinically or radiologically diagnosed osteoporosis.

Exclusion Criteria:

Women with secondary causes of osteoporosis (e.g., hyperparathyroidism, chronic renal disease, malignancy).

Current use of Vitamin D or calcium supplementation within the past 3 months.

Patients on corticosteroids or other medications affecting bone metabolism.

Data Collection and Laboratory Analysis:

Demographic details, clinical history including duration of menopause and history of fragility fractures, were recorded using a structured proforma. Venous blood samples were collected under aseptic precautions. Serum 25-hydroxyvitamin D [25(OH)D] levels were measured using chemiluminescent immunoassay, and total serum calcium was estimated using an automated colorimetric method.

Vitamin D status was categorized as:

Deficiency: <20 ng/mL

Insufficiency: 20–30 ng/mL

Sufficiency: >30 ng/mL

Serum calcium levels were interpreted as:

Hypocalcemia: <8.5 mg/dL

Normocalcemia: 8.5–10.5 mg/dL

Hypercalcemia: >10.5 mg/dL

Statistical Analysis:

Data were entered in Microsoft Excel and analyzed using SPSS version 26.0. Descriptive statistics were presented as means ± standard deviation (SD) or percentages as appropriate. Pearson correlation coefficient was used to assess the association between serum Vitamin D and calcium levels. A p-value <0.05 was considered statistically significant.

Ethical Considerations:

Necessary permissions were taken from concerned authorities before starting the study. Written informed consent was obtained from all participants prior to enrollment.

A total of 100 postmenopausal women diagnosed with osteoporosis were enrolled in this hospital-based observational study. The mean age of the participants was 62.7 ± 7.8 years, with an age range of 51 to 78 years (Table 1). A subset of participants reported a history of fragility fractures, although the mean duration since menopause was not uniformly available.

Table 1: Demographic Profile of Participants (N = 100)

Analysis of serum 25-hydroxyvitamin D [25(OH)D] levels revealed a mean concentration of 16.2 ± 6.4 ng/mL, indicating widespread deficiency. Vitamin D deficiency (<20 ng/mL) was observed in 76% of participants, insufficiency (20–30 ng/mL) in 18%, and sufficiency (>30 ng/mL) in only 6% (Table 2).

Table 2:  Serum Vitamin D Status Among Participants

Figure 1. Serum Vitamin D Status Among Participants

Regarding serum calcium levels, the cohort demonstrated a mean total calcium of 8.3 ± 0.7 mg/dL. Hypocalcemia (<8.5 mg/dL) was present in 58% of participants, while 42% had normocalcemia (8.5–10.5 mg/dL). No cases of hypercalcemia were recorded (Table 3).

Table 3: Serum Calcium Levels Among Participants

Figure 2. Serum Calcium Levels Among Participants

A statistically significant positive correlation was observed between serum Vitamin D and calcium levels (Pearson’s r = 0.41, p < 0.001), suggesting a concurrent deficiency pattern (Table 4). Notably, 48% of the participants had both Vitamin D deficiency and hypocalcemia, highlighting a compounded biochemical risk. An inverse correlation was also noted between duration of menopause and serum Vitamin D levels (r = –0.22, p = 0.03), though the strength of association was weak. Furthermore, participants with a history of fragility fractures exhibited significantly lower mean Vitamin D levels (13.8 ng/mL) compared to those without fractures (17.9 ng/mL, p = 0.01) (Table 4).

Table 4: Correlation and Additional Observations

This study reaffirms the high prevalence of biochemical deficiencies—particularly Vitamin D and calcium—among postmenopausal women with osteoporosis, emphasizing a critical concern in their clinical management. The mean serum 25(OH) Vitamin D level in our cohort was 16.2 ± 6.4 ng/mL, with 76% of participants exhibiting deficiency (<20 ng/mL). These findings are consistent with regional and international studies, which have reported widespread hypovitaminosis D in postmenopausal women due to reduced cutaneous synthesis, inadequate dietary intake, and low sun exposure [7,10].

Only 6% of our participants met the sufficiency threshold (>30 ng/mL), reflecting a gap between optimal levels and real-world status. A similar trend has been reported in observational studies from Europe and Asia, underscoring the global nature of this issue [8,10]. The study by Suganthan et al. in Sri Lanka found comparable levels of deficiency, highlighting the importance of localized assessments and interventions [10].

In our cohort, hypocalcemia (<8.5 mg/dL) was also noted in 58% of patients, and notably, 48% had both Vitamin D deficiency and hypocalcemia. This co-occurrence emphasizes the physiological interplay between these nutrients. Vitamin D promotes calcium absorption; its deficiency leads to secondary hyperparathyroidism, increased bone resorption, and compromised bone health [9,12]. The observed positive correlation between serum Vitamin D and calcium (r = 0.41, p < 0.001) aligns with earlier findings linking biochemical status to skeletal integrity and metabolic regulation [9].

The mean Vitamin D levels were significantly lower in women with prior fragility fractures (p = 0.01), corroborating earlier studies that demonstrate a direct association between Vitamin D deficiency and increased fracture risk [11]. Lee and Kim observed similar trends in high- and low-energy fracture patients, suggesting that inadequate Vitamin D status impairs muscle strength and balance, increasing fall susceptibility and fracture rates [11].

We also identified a weak inverse correlation between the duration of menopause and Vitamin D levels (r = –0.22, p = 0.03), suggesting progressive depletion over time. A recent study by Wang et al. on middle-aged and elderly women similarly demonstrated reduced Vitamin D levels with advancing age, supporting our findings [12].

Despite its strengths, the study has limitations. Bone mineral density (BMD) data were not uniformly available, which may restrict the diagnostic correlation. Additionally, dietary intake, PTH levels, and sun exposure were not assessed, limiting the scope of causative interpretation. Nevertheless, our results align with global evidence advocating for routine screening and timely supplementation of Vitamin D and calcium in postmenopausal osteoporotic women [7,8,10].

This study demonstrates a high prevalence of Vitamin D deficiency and hypocalcemia among postmenopausal women with osteoporosis, emphasizing a critical gap in routine nutritional assessment. The significant positive correlation between serum Vitamin D and calcium levels highlights the physiological link and the compounded risk when both are deficient. Additionally, the association between lower Vitamin D levels and history of fragility fractures underscores its clinical relevance in fracture prevention. These findings support the need for regular screening and early correction of micronutrient deficiencies as part of comprehensive osteoporosis management. Public health initiatives promoting awareness, dietary guidance, and supplementation could substantially improve bone health outcomes in this high-risk population.

1. Narula R, Tauseef M, Ahmad IA, Agarwal K, Ashok A, Anjana A. Vitamin d deficiency among postmenopausal women with osteoporosis. J Clin Diagn Res. 2013 Feb;7(2):336-8. doi: 10.7860/JCDR/2013/5022.2761. Epub 2013 Jan 8. PMID: 23543783; PMCID: PMC3592305.
2. Voulgaridou G, Papadopoulou SK, Detopoulou P, Tsoumana D, Giaginis C, Kondyli FS, Lymperaki E, Pritsa A. Vitamin D and Calcium in Osteoporosis, and the Role of Bone Turnover Markers: A Narrative Review of Recent Data from RCTs. Diseases. 2023 Feb 8;11(1):29. doi: 10.3390/diseases11010029. PMID: 36810543; PMCID: PMC9944083.
3. Migliorini F, Maffulli N, Colarossi G, Filippelli A, Memminger M, Conti V. Vitamin D and calcium supplementation in women undergoing pharmacological management for postmenopausal osteoporosis: a level I of evidence systematic review. Eur J Med Res. 2025 Mar 14;30(1):170. doi: 10.1186/s40001-025-02412-x. PMID: 40087804; PMCID: PMC11907966.
4. Aloia JF, Dhaliwal R, Shieh A, Mikhail M, Islam S, Yeh JK. Calcium and vitamin d supplementation in postmenopausal women. J Clin Endocrinol Metab. 2013 Nov;98(11):E1702-9. doi: 10.1210/jc.2013-2121. Epub 2013 Sep 24. PMID: 24064695.
5. G Siregar MF, Jabbar F, Effendi IH, Alhair T, Prabudi MO, Faradina D. Correlation between serum vitamin D levels and bone mass density evaluated by radiofrequency echographic multi-spectrometry technology (REMS) in menopausal women. Narra J. 2024 Apr;4(1):e452. doi: 10.52225/narra.v4i1.452. Epub 2024 Apr 30. PMID: 38798836; PMCID: PMC11125322.
6. Aggarwal S, Nityanand. Calcium and vitamin D in post menopausal women. Indian J Endocrinol Metab. 2013 Dec;17(Suppl 3):S618-20. doi: 10.4103/2230-8210.123549. PMID: 24910823; PMCID: PMC4046613.
7. Wang D, Yang Y. The Relationship Between Serum 25-Hydroxyvitamin D Levels and Osteoporosis in Postmenopausal Women. Clin Interv Aging. 2023 Apr 18;18:619-627. doi: 10.2147/CIA.S405317. PMID: 37096217; PMCID: PMC10122466.
8. Fan T, Nocea G, Modi A, Stokes L, Sen SS. Calcium and vitamin D intake by postmenopausal women with osteoporosis in Spain: an observational calcium and vitamin D intake (CaVIT) study. Clin Interv Aging. 2013;8:689-96. doi: 10.2147/CIA.S41335. Epub 2013 Jun 19. PMID: 23818767; PMCID: PMC3693746.
9. Guney G, Sener-Simsek B, Tokmak A, Yucel A, Buyukkagnici U, Yilmaz N, Engin-Ustun Y, Ozgu-Erdinc AS. Assessment of the Relationship between Serum Vitamin D and Osteocalcin Levels with Metabolic Syndrome in Non-Osteoporotic Postmenopausal Women. Geburtshilfe Frauenheilkd. 2019 Mar;79(3):293-299. doi: 10.1055/a-0767-6572. Epub 2019 Jan 22. PMID: 30880828; PMCID: PMC6414302.
10. Suganthan N, Kumanan T, Kesavan V, Aravinthan M, Rajeshkannan N. Vitamin D status among postmenopausal osteoporotic women: a hospital based cross-sectional study from Northern Sri Lanka. BMC Nutr. 2020 Mar 18;6:15. doi: 10.1186/s40795-020-00341-y. PMID: 32206326; PMCID: PMC7081545.
11. Lee JS, Kim JW. Prevalence of vitamin D deficiency in postmenopausal high- and low-energy fracture patient. Arch Osteoporos. 2018 Oct 10;13(1):109. doi: 10.1007/s11657-018-0524-7. PMID: 30306272.
12. Wang Z, Yao G, Tao X, Zhang J, Zhang T, Wu Z. Evaluation of bone mineral density and 25-(OH) vitamin D levels in middle-aged and elderly women with recurrent benign paroxysmal positional vertigo. Acta Otolaryngol. 2020 Feb;140(2):89-93. doi: 10.1080/00016489.2019.1692146. Epub 2019 Dec 26. PMID: 31876211.