Leiomyoma or Uterine fibroids (UFs) are a women’s health care concern with a public bearing. Uterine fibroids (UFs) are the most common benign pathology of female genital tract with 5-70% of women developing the tumor. By the age of 50 years, 77% of women get these monoclonal tumours, whereas they manifest clinically in only 25%–50% of women.  Even though these tumours are benign, they have significant morbidity involving anemia, abnormal uterine bleeding, subfertility, pelvic pain, and obstetric complications like miscarriage and premature labor, anemia, gastric disorders like bloating, constipation, and voiding symptoms. Also, these tumours are responsible for reproductive dysfunction and are considered to be the main sign for hysterectomy. All these factors adversely affect a woman’s quality of life.¹

Tumor development begins with the creation of a pathologically changed and transformed primary myometrial cell. Subsequently, all secondary cells divide, making the tumor grow further.Histologically, UFs structure is composed of a fibrovascular pseudocapsule surrounding a tissue consisting of smooth muscle cells, fibroblasts, and connective tissue. The mechanisms controlling the growth of UFs are complex and still not well-recognized. Abnormal and excessive extracellular matrix production is a major factor in UF growth.² The main hormones which simulate UFs development and growth are estrogen and progesterone; which induce UF formation and growth through various growth factors.

Vitamin D is a prohormone produced in the skin via a sunlight-initiated reaction and converted to the active metabolite 1, 25-dihydroxyvitamin D₃ mainly in the liver and kidneys. It exerts its effects via activation of its cellular receptor (vitamin D receptor), which in turn alters the transcription rates of target genes responsible for various biological responses.

Vitamin D is an antifibrotic factor and inhibits growth as it is found to induce apoptosis in cultured human leiomyoma cells through the downregulation of the genes PCNA, CDK1, and BCL-2 and suppression of catechol-o-methyltransferase expression and activity in human leiomyoma cells.^3-5 Laboratory studies of fibroid tissue on culture that were treated with calcitriol, the active form of vitamin D, demonstrate reduction in cell proliferation and extracellular matrix production.⁶ Additionally, recent studies have demonstrated that vitamin D is a potent anti-tumor agent that effectively inhibits human uterine fibroid cells in vitro and shrinks fibroid lesions in preclinical animal studies.⁷

A review of the literature indicated that not many studies investigated vitamin D levels in patients with UFs. Clearly, several clinicians might be unaware that vitamin D deficiency may contribute to UF development.So a study of vitamin D levels in women having leiomyoma was planned to establish their association.

This cross sectional observational study was conducted in the Department of Obstetrics and Gynaecology, Sardar Patel Medical College, Bikaner for a period of 1 year (August 2023 to July 2024).Premenopausal women 18-45 years of age attending gynaecological outpatient department with different complaints matching for age and BMI were recruited to the study. Those patients especially coming with complaints of abnormal uterine bleeding were approached to participate.

50 patients with at least one fibroid lesion with a mean volume of ≥ 2cm³ were taken as cases. The rest 50 patients who had normal uterine morphology on ultrasonography were approached to participate as controls.

Following women were excluded from our study:

• Current pregnancy or pregnancy within the last 6 months
• Currently lactating or lactating within the last 6 months
• History of abortion within 6 months prior to start of study
• History of myomectomy
• Women currently using vitamin D supplements or hormonal treatment (including oral contraceptives) or history of use within the last 6 months.
• Women with intrauterine fibroid of < 2 cm³ in volume on TAS
• Women diagnosed with adenomyosis and other causes of abnormal uterine bleeding.
• Non consenting women

The goal and methodology of the study was described to all patients after approval of hospital ethics committee. Both verbal and written consents were taken from the patients.On recruitment into study, a structured proforma was used to collect data regarding socio- demographic details, age at menarche, use of oral contraceptives, presenting complaints, obstetric and family history. Anthropometric measurements (weight and height) were taken.Basic investigations like haemogram, blood sugar, LFT, KFT and routine urine examination were done. Patients were subjected to transabdominal ultrasound (TAS).The number of fibroid lesions, volume, and location of all fibroid lesions were accurately noted. The volume of each fibroid was determined according to the ellipsoid formula (a × b × c × 0.523), where a is the height, b is the width, and c is the depth (in cm). The total volume of fibroid in a patient was calculated by adding the volumes of all lesions detected. The location of each fibroid lesion within the uterus was classified as submucosal, intramural, or subserosal.2 ml of venous blood sample in plain vial was collected from selected women. The quantitative detection of vitamin D levels was performed using chemiluminescence assay. After testing for vitamin D levels, the WHO mandated criteria was applied to classify them in 3 groups as (a) deficient: <10 ng/ml; (b) insufficient: 10-20 ng/ml; (c) sufficient: >20 ng/ml. Data was collected, compiled,statistical analysis was done using suitable tests of significance and valid conclusions were drawn. A p value less than 0.05 was taken to indicate a significant difference.

The primary outcome measured were vitamin D deficiency among women with uterine fibroids and the secondary outcome measured were its correlation with fibroid number, location and volume.

In this cross-sectional observational study done at SPMC, Bikaner we found that the mean age distribution of case group was 38.82 ± 3.06 years and control group was 38.84 ± 3.94 years (p>0.05).We are at a tertiary care centre in which maximum cases are referred from rural area and belong to low socioeconomic status; as highlighted in the demographic profile (Table 1). Overall, the study demographics of the population showed that the cases were comparable to controls in terms of age, residence, education and parity. This ensured that these factors did not have any effect on the difference in the vitamin D levels and the occurrence of uterine fibroids among the two groups.

Table 1. Demographic characteristics of study population

An incidental significant association was found between BMI and occurrence of fibroid. The mean BMI among cases and controls was 25.1 ± 3.47 kg/m² and 22.18 ± 1.86 kg/m² respectively (p value 0.0001*). So, obesity could be considered a risk factor for uterine fibroid. 

Table 2: Distribution of cases and controls according their BMI   

Majority of the cases had complaints of irregular menstruation/ HMB (80%), followed by pain abdomen (46%), anemia (30%), dysmenorrhea (14%) and lump abdomen (6%).

Figure 1: Distribution of cases and controls according to chief complaint

• The mean value of vitamin D in case group and control group was 13.61 ± 5.67 ng/ml and 19.69 ± 9.42 ng/ml respectively. The difference was found to be statistically significant (p=0.0002**) denoting a possible inverse correlation between serum vitamin D level and uterine fibroid.
• There was an association found between multiple fibroids with deficient vitamin D levels Maximum number of women with single fibroid had insufficient vitamin D level i.e, 90.9% (30/33) cases followed by 6.06% (2/33) cases had sufficient vitamin D level and minimum i.e., 3.03% (1/33) cases had deficient vitamin D level. Maximum number of women with multiple fibroid had deficient vitamin D level i.e., 82.35% (14/17) cases followed by 11.76% (2/17) cases had insufficient vitamin D level and minimum i.e., 5.88% (1/17) cases had sufficient vitamin D level. The difference was found to be statistically significant. (p=0.013**)
• The most common fibroid lesion found was intramural in 32 cases, followed by submucosal in 14 cases and subserosal in 4 cases. An association was found between vitamin D levels and location of the fibroid lesion (p = 0.042).
• The total fibroid volume in the study group ranged from a minimum of 2 cm³ to a maximum of 250 cm³ with a mean of 77.28 ± 69.34 cm³. Among 15 women with deficient vitamin D levels, 46.67% (7/15) had fibroid volume <100cm³, 40% (6/15) women had fibroid volume between 101-200 cm³ and 13.3% (2/15) women had fibroid volume >200cm³. Among the 32 women with insufficient vitamin D levels, 50% (16/32) had fibroid volume <100cm³, 46.87% (15/32) women had fibroid volume between 101-200 cm³ and 3% (1/32) women had fibroid volume >200cm³.On the other hand, among women with sufficient vitamin D levels, majority (66.67%) had fibroid volume of < 100 cm³. However the result was not found to be statistically significant (p > 0.05).

Table 3: Distribution of cases and controls according to vitamin D levels

Table 4: Distribution of women based on number of fibroid among cases with relation to vitamin D level

Table 5: Distribution of women based on location of fibroid among cases with relation to vitamin D levels

Table 6: Distribution of women based on volume of fibroid among cases with relation to vitamin D levels

The present study was a cross sectional observational study conducted on 100 premenopausal women (50 case group and 50 control group) aged between 18-45 years attending gynecological outpatient department at Sardar Patel Medical College & AGH, Bikaner, Rajasthan, during a period of 1 year starting from August 2023 to July 2024.

This study was conducted with the primary focus to estimate and compare the vitamin D level in patients with fibroid uterus and patients without fibroid uterus. Secondary aim was to correlate number, location and volume of leiomyoma with vitamin D deficiency andto study the role of vitamin D as a potential protective factor against the development of leiomyoma.

In our study, the mean age distribution of case group was 38.82 ± 3.06 years and control group was 38.84 ± 3.94 years. Both groups were comparable in terms of their age. There was no statistically significant difference observed in the mean age of cases and controls (p=0.977). The result of our study was similar to some of the previous studies. Choudhary S et al⁸ found that the mean age among the cases was 39.11±6.05 years and controls was 38.84±5.75 years (p=0.85). Ajmani et al⁹ found that the mean age among the cases was 36.79±8.97 years and controls was 38.60±7.78 years. Oskovi et al¹⁰ showed that the mean age of the cases was 38.25±4.88 years and controls was 39.84±3.99 years (p value=0.09).

In our study mean BMI among cases and controls was 25.1 ± 3.47 kg/m² and 22.18 ± 1.86 kg/m² respectively. There was significant association found between BMI and occurrence of fibroid in this study (p value 0.0001**). So, obesity could be considered a risk factor for uterine fibroid. Our findings are also in line with the results of Choudhary S et al⁸ who found that the mean BMI in case and control group was 25.8±3.77 kg/m² and 24.07±3.49 kg/m² respectively and significant association was found between BMI and occurrence of fibroid (p value=0.0277 and odds ratio=2.15). Similar outcome was found by Ciebierain et al¹¹ in which mean BMI in case and control group was 26.67±5.01 kg/m² and 24.03±4.47 kg/m² respectively and significant association was found between BMI and occurrence of fibroid (p value=0.0002).

Our study exhibited lower serum vitamin D levels in women with fibroid as compared to control group (13.61 ± 5.67 ng/ml vs. 19.69 ± 9.42 ng/ml). The difference was found to be statistically significant (p=0.0002**). On categorical analysis of vitamin D according to WHO criteria, we found that 64% of women with fibroid and 82% of controls had insufficient vitamin D levels (10-20 ng/ml). 30% of women with fibroid were associated with vitamin D deficiency (<10 ng/ml) as compared to 2% controls. Moreover, only 6% of women with fibroid as compared to 16% controls had sufficient vitamin D levels (>20ng/ml). This finding suggests a possible inverse correlation between serum vitamin D level and uterine fibroid in the present study population which corroborates the results of the studies conducted on different populations across the world. Our findings are also in tune with that of Choudhary S et al⁸ as there were lower mean serum vitamin D level in women with fibroid than controls (12.81±8.56 ng/ml vs. 19.83±9.21 ng/ml with p value<0.0001). In a similar analysis by Ajmani et al⁹, they found that the mean level of vitamin D in the case group was 12.58±4.09 ng/ml, while in the control group was 18.99±5.72 ng/ml (p=0.001).Ruchi Kumari et al¹²found that the mean serum 25-hydroxyvitamin D₃ level in the study and control group was 14.52 ± 7.89 ng/mL and 26.6 ± 14.36 ng/mL respectively (p < 0.05). 25-hydroxyvitamin D₃ deficiency was more common in the study group (54.90%) compared to healthy controls (6.7%) while sufficiency was more common among controls (67.8% vs. 27.45), the difference being statistically significant (p < 0.05). Even in the study by Vinita Singh et al¹³, theyfoundthatthe mean serum concentration of vitamin D₃ was significantly lower in women with uterine fibroids as compared to controls (10.81± 6.18 vs. 22.91 ± 16.18, p<0.0001).

 The present study revealed a statistically significant difference between low levels of serum vitamin D and location and number of fibroids but none with volume of fibroid.

Ruchi Kumari et al¹²however found a significant inverse correlation between serum 25-hydroxyvitamin D₃levels and total volume of fibroids (p = 0.000) while none between 25-hydroxyvitamin D₃levels with location, number of fibroids.

The role of vitamin D in the development, growth, or both of UFs can be clarified by more thorough prospective cohort studies that include serial ultrasound imaging for uterine morphology at predetermined time intervals and monitoring of vitamin D status. Due to its hospital setting, the study might not accurately reflect the actual burden in terms of community demographics. Therefore, we propose that vitamin D deficiency could contribute to the development of UFs.

Our study showed a definite indirect association between low serum vitamin D levels and the occurrence of uterine fibroids.There was a negative association between vitamin D and the number of fibroid in the case group, suggesting the regulatory role of vitamin D in the growth of uterine muscle cells. This opens up an interesting facet that vitamin D supplementation would have the potential to become a simple and economical means to prevent fibroids development or growth. Further investigations could establish vitamin D or its analogues, as a novel oral noninvasive therapeutic/ preventive agent for this common disease, which would have a major positive impact on women’s health worldwide.

Funding: No funding sources

Conflict of interest:  None declared

Ethical committee clearance:We obtained approvals from department research review board and institute ethics committee prior to commencement of the study.

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