Evaluation of IL-6, TGF-β1, CRP, and Vitamin D Levels in Women with Uterine Fibroids

Navya; Dr. Meenakumari

doi:10.65188/nurexus.1017

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Journal of MedVerse Research & Practice

nurexus.com

Evaluation of IL-6, TGF-β1, CRP, and Vitamin D Levels in Women with

Uterine Fibroids

Dr. Navya

1

, Dr. Meenakumari

2

Postgraduate, Associate Professor

Department of OBG, Madha Medical College Hospital, Chennai

Mail ID: navya562@gmail.com

Submission Date:19.02.2025

Accepted Date:18.03.2025

Published Date:31.03.2025

DOI: 10.65188/nurexus.1017

article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits

unrestricted use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.

Abstract

Introduction: Uterine fibroids, also known as leiomyomas, are the most prevalent benign tumors found in women

of reproductive age. Their growth is influenced by various inflammatory markers and hormonal factors. Key

elements such as Interleukin-6 (IL-6), Transforming Growth Factor-Beta 1 (TGF-β1), C-reactive protein (CRP),

and vitamin D have been associated with the development and progression of fibroids. This research aimed to

assess the serum concentrations of IL-6, TGF-β1, CRP, and vitamin D in women diagnosed with uterine fibroids to

explore their potential roles in the severity and progression of the condition.

Materials & Methods: A case-control study was carried out involving 50 women diagnosed with uterine fibroids

and 50 age-matched healthy controls. The serum concentrations of IL-6, TGF-β1, CRP, and vitamin D were

quantified through enzyme-linked immunosorbent assay (ELISA). Data analysis was performed using SPSS, with

statistical significance determined at a p-value of less than 0.05.

Results: Women with uterine fibroids exhibited notably higher serum concentrations of IL-6 (6.12 ± 1.92 pg/mL

vs. 8.01 ± 1.25 pg/mL, p = 0.000), TGF-β1 (3.056 ± 0.9 ng/mL vs. 2.1 ± 0.235 ng/mL, p = 0.001), and CRP (45.23

± 4.6 mg/L vs. 43.5 ± 4.2 mg/L, p = 0.000) compared to healthy controls. In contrast, vitamin D levels were

significantly lower in the fibroid group (63.25 ± 7.02 ng/mL vs. 44.2 ± 8.6 ng/mL, p = 0.02). Correlation analysis

revealed that IL-6, TGF-β1, and CRP levels were positively correlated with both the size and number of fibroids,

while vitamin D displayed an inverse relationship.

Conclusion: Increased levels of IL-6, TGF-β1, and CRP indicate a significant inflammatory contribution to the

development of uterine fibroids, whereas reduced vitamin D levels suggest a possible protective role. These results

highlight the potential impact of inflammatory control and vitamin D supplementation in managing fibroids. Future

longitudinal research is needed to establish causal links and assess therapeutic possibilities.

Keywords: Uterine fibroids, IL-6, TGF-β1, CRP, Vitamin D, Inflammation, Biomarkers

Introduction

Uterine fibroids, clinically referred to as leiomyomas, represent the most prevalent form of benign tumors

encountered in women who are of reproductive age, thus posing significant health concerns within this

demographic. These tumors arise from the smooth muscle cells that constitute the uterine wall and exhibit

considerable variability in both their size and the number of lesions present within an individual. While it

is true that a subset of women may remain asymptomatic and experience no adverse effects, a notable

proportion may suffer from a range of symptoms such as excessive menstrual bleeding, pelvic pain or

ORIGINAL ARTICLE

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discomfort, infertility, and various pressure-related symptoms that can adversely affect adjacent organs

within the pelvic cavity. Despite extensive research efforts, the specific etiological factors responsible for

the formation of fibroids remain largely elusive; however, it is widely acknowledged that their

development is influenced by a complex interplay of hormonal, genetic, and inflammatory mechanisms.

(1,2). Recent scientific studies have brought to light the significant role played by inflammatory

cytokines, growth factors, and the vitamin D hormone in both the initiation and progression of fibroid

tumors, thereby suggesting multiple potential pathways for improved diagnostic measures and therapeutic

interventions.

Interleukin-6 (IL-6) is characterized as a pro-inflammatory cytokine that has been identified as having

crucial roles in mediating immune responses, facilitating cell growth, and orchestrating tissue remodeling

processes. Elevated concentrations of IL-6 have been associated with numerous inflammatory disorders

and are posited to contribute to the pathogenesis of fibroids by promoting cellular proliferation alongside

the accumulation of extracellular matrix components. In a similar vein, transforming growth factor-beta 1

(TGF-β1) serves as a pivotal regulator in the process of fibrosis, encouraging an overproduction of

extracellular matrix components within fibroid tissues. The overexpression of TGF-β1 has been linked to

increased collagen deposition and heightened tissue stiffness, thereby establishing it as a significant target

for potential antifibrotic therapeutic strategies aimed at ameliorating the condition. (3,4)

C-reactive protein (CRP) is classified as an acute-phase protein and is widely acknowledged as a reliable

biomarker of systemic inflammation. The presence of elevated CRP levels among women diagnosed with

fibroids serves to indicate a chronic inflammatory state, thereby reinforcing the hypothesis that persistent

inflammation plays an integral role in the pathogenesis of fibroids5. The intricate and complex

interactions between various inflammatory markers and the processes involved in fibroid formation

necessitate further investigation to elucidate their respective roles as potential indicators of the severity

and progression of this condition. (5,6,7)

Vitamin D has recently garnered attention as a potential protective factor that may mitigate the risk of

developing fibroids. Emerging research suggests that vitamin D possesses the capability to inhibit the

proliferation of fibroid cells while concurrently decreasing the production of extracellular matrix

components. Furthermore, lower serum levels of vitamin D have been correlated with an elevated risk of

fibroid development, thereby implying that vitamin D supplementation could represent a plausible

preventive or therapeutic approach to managing this condition6. A thorough investigation into the

relationship between vitamin D deficiency and the growth of fibroids may yield valuable insights into

innovative treatment modalities that harness its anti-inflammatory and antifibrotic properties. The

objective of this research endeavor is to assess the serum concentrations of key biomarkers, including IL-

6, TGF-β1, CRP, and vitamin D in women who have been diagnosed with uterine fibroids, to examine

their potential correlations with the development, severity, and progression of fibroid tumors. (8,9)

Material & Methods

Study Design and Setting

A case-control study was conducted at the Department of Obstetrics and Gynecology, Madha Medical

College Hospital, Chennai, to evaluate the association between selected biochemical markers and uterine

fibroids in 2 years suration from Jan 2023 to Dec 2024.

Study Population

The study included 100 women aged 20–80 years. The participants were divided into two groups: 50

women diagnosed with uterine fibroids constituted the case group, while 50 age-matched healthy women

served as the control group. Participants were recruited from the outpatient clinics.

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Inclusion Criteria

Women aged 20–80 years who were willing to participate and provide informed consent were included.

Women diagnosed with uterine fibroids by ultrasound examination were included in the case group, while

age-matched healthy women without uterine fibroids were included as controls.

Exclusion Criteria

Women with malignancies, autoimmune diseases, chronic inflammatory conditions, or those receiving

hormone therapy were excluded from the study.

Data Collection Procedure

After obtaining informed consent, relevant clinical information was collected from all participants. The

diagnosis of uterine fibroids was confirmed using ultrasound imaging. Fasting venous blood samples were

collected from both cases and controls. Serum levels of interleukin-6 (IL-6), transforming growth factor-

beta 1 (TGF-β1), C-reactive protein (CRP), and vitamin D were estimated using commercially available

ELISA kits according to the manufacturer's instructions. The biochemical findings were subsequently

compared between women with uterine fibroids and healthy controls. Correlation analysis was performed

to assess the relationship between the biochemical markers and the severity of uterine fibroids.

Statistical Analysis

Data were analysed using IBM SPSS Statistics, version 26.0. Continuous variables were summarized

using means and standard deviations or medians and interquartile ranges, as appropriate. The distribution

of continuous variables was assessed before selecting parametric or non-parametric tests. Between-group

comparisons were performed using the appropriate statistical test, which is identified for each analysis in

the Results section. Associations between biomarker concentrations and fibroid size or number were

assessed using Pearson or Spearman correlation, as appropriate. Correlation coefficients and

corresponding p-values were reported. A two-sided p-value of less than 0.05 was considered statistically

significant.

Ethical Considerations

Informed consent was obtained from all participants before enrollment. The study was conducted

following appropriate ethical principles, and confidentiality of participant information was maintained

throughout the study.

Results

Serum Levels of IL-6, TGF-β1, CRP, and Vitamin D

Table 1 presents a comparative analysis of serum biomarkers, including Interleukin-6 (IL-6),

Transforming Growth Factor Beta 1 (TGF-β1), C-reactive protein (CRP), and Vitamin D, in women with

uterine fibroids and healthy controls. These biomarkers are key regulators of inflammation, fibrosis, and

immune response, all of which play a critical role in fibroid development and progression.

Table 1: Comparison of Serum Biomarker Levels Between Fibroid and Control Groups

In the present study, inflammatory and metabolic biomarkers showed significant differences between

Biomarker

Fibroid Group (Mean ± SD)

Control Group (Mean ± SD)

p-value

IL-6 (pg/mL)

6.12 ± 1.92

8.01 ± 1.25

0.000

TGF-β1

(ng/mL)

3.056± 0.9

2.1± 0.235

0.001

CRP (mg/L)

45.23 ± 4.6

43.5±4.2

0.000

Vitamin D

(ng/mL)

63.25± 7.02

44.2 ± 8.6

0.02

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fibroid patients and healthy controls. The mean IL-6 level in the fibroid group (6.12 ± 1.92 pg/mL) was

markedly higher than that of the control group (8.01 ± 1.25 pg/mL, p = 0.000), highlighting the role of

this pro-inflammatory cytokine in promoting inflammation and tissue remodeling associated with fibroid

development. Similarly, serum TGF-β1 levels were elevated among fibroid patients (3.056 ± 0.9 ng/mL)

compared to controls (2.1 ± 0.235 ng/mL, p = 0.001), suggesting its involvement in fibrosis and

extracellular matrix deposition that contribute to fibroid formation. The mean CRP level was also

significantly increased in the fibroid group (45.23 ± 4.6 mg/L) relative to controls (43.5 ± 4.2 mg/L, p =

0.000), reflecting a persistent inflammatory state that may play a role in disease progression. Conversely,

Vitamin D levels were notably lower in women with fibroids (44.2 ± 8.6 ng/mL) than in healthy subjects

(63.25 ± 7.02 ng/mL, p = 0.02), implying a potential protective role of Vitamin D against fibroid growth

and progression.

Table 2: Correlation Between Biomarkers and Fibroid Severity

Table 2 shows the correlation between serum biomarker levels and fibroid severity, categorized by size

and number. These associations provide insight into how inflammation, fibrosis, and vitamin D levels

affect the growth and progression of uterine fibroids. IL-6 levels were significantly elevated in patients

with larger fibroids (46.89 ± 7.92) and multiple fibroids (43 ± 6.5), indicating that inflammation

contributes to both fibroid growth and multiplicity. This pro-inflammatory cytokine promotes cellular

proliferation and extracellular matrix deposition, key factors in fibroid expansion. Similarly, TGF-β1

levels were higher in patients with larger fibroids (4.72 ± 0.74) and multiple fibroids (3.51 ± 0.52),

confirming its role in fibroid stiffness and growth through excessive collagen deposition. CRP, an acute-

phase marker of systemic inflammation, was elevated in women with larger fibroids (6.821 ± 1.23) and

multiple fibroids (5.269 ± 2.369), further supporting the hypothesis that chronic inflammation plays a key

role in fibroid pathology. Vitamin D levels were lower in women with larger fibroids (50.2 ± 6.32) and

multiple fibroids (54.2 ± 8.23), suggesting that vitamin D deficiency may contribute to fibroid growth.

These findings highlight the potential protective role of vitamin D against fibroid progression, in line with

its anti-inflammatory and antifibrotic properties.

Discussion

The present study evaluated the levels of inflammatory and fibrotic biomarkers, including interleukin-6

(IL-6), transforming growth factor-beta 1 (TGF-β1), and C-reactive protein (CRP), along with vitamin D

levels, among women with uterine fibroids and healthy controls. These biomarkers may provide insights

into the inflammatory and fibrotic mechanisms associated with uterine fibroid development. However, the

findings must be interpreted in the context of the study design, the consistency of the reported results, and

the limitations of the available statistical analyses.

Interleukin-6 and Inflammatory Pathways

Interleukin-6 is a pro-inflammatory cytokine involved in immune regulation, cellular signalling, and

tissue responses to inflammation. In uterine fibroids, inflammatory signalling may interact with hormonal

regulation, cellular proliferation, and extracellular matrix remodelling. Previous investigations have

examined the potential involvement of inflammatory cytokines in fibroid pathogenesis, suggesting that

Parameter

Fibroid Size (r-value)

Fibroid Number (r-value)

IL-6

46.89 ± 7.92

43 ± 6.5

TGF-β1

4.72± 0.74

3.51± 0.52

CRP

6.821 ± 1.23

5.269±2.369

Vitamin D

50.2± 6.32

54.2± 8.23

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inflammatory pathways may contribute to the local tissue environment in which fibroids develop [1–3].

IL-6-related signalling may influence cellular responses through pathways involved in inflammation and

cell survival. The nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3

(STAT3) pathways have also been investigated in relation to inflammatory processes and fibroid biology

[3]. These mechanisms provide a biological rationale for studying IL-6 in women with uterine fibroids.

Nevertheless, the presence of an inflammatory marker does not establish that inflammation initiated

fibroid development or directly caused fibroid enlargement.

In the present study, the reported IL-6 concentrations require verification because the group means in the

abstract and Table 1 indicate lower levels in the fibroid group than in controls, whereas the Results

narrative describes elevated levels among women with fibroids. This discrepancy must be resolved using

the original laboratory dataset before the direction of the difference can be interpreted. Until then, the

study cannot conclusively support the claim that IL-6 was elevated in women with uterine fibroids. Future

studies should examine IL-6 alongside clinical characteristics, fibroid dimensions, hormonal status, and

other potential confounding factors to clarify its clinical relevance.

Transforming Growth Factor-Beta 1 and Fibrotic Remodelling

Transforming growth factor-beta 1 is an important regulator of tissue repair, extracellular matrix

production, and fibrotic remodelling. Excessive extracellular matrix accumulation is a recognised feature

of uterine fibroid tissue and contributes to its structural characteristics. TGF-β1-related signalling is

therefore relevant to investigations of the biological mechanisms underlying fibroid formation and growth

[4,5]. TGF-β1 signalling can activate downstream pathways involved in the production and regulation of

extracellular matrix components. Smad-dependent signalling is one of the mechanisms investigated in

fibrotic processes, including those associated with uterine fibroids [5]. Alterations in these pathways may

contribute to differences in tissue composition and mechanical properties. However, the degree to which

these mechanisms determine clinical severity, symptoms, or fibroid growth cannot be established from

circulating biomarker measurements alone.

In the present study, the reported mean TGF-β1 concentration was higher in the fibroid group than in the

control group. If these values are confirmed against the original data and the statistical analysis is valid,

the finding would be consistent with a possible association between TGF-β1 levels and uterine fibroids.

Nevertheless, a higher circulating concentration does not directly demonstrate increased TGF-β1 activity

within fibroid tissue. Tissue-based analyses and longitudinal studies would be useful to investigate

whether circulating levels correspond to local fibrotic activity and changes in fibroid dimensions.

C-Reactive Protein and Systemic Inflammation

C-reactive protein is a systemic inflammatory marker produced primarily by the liver in response to

inflammatory signalling. Its concentration may be influenced by several conditions, including infection,

obesity, metabolic disorders, and other inflammatory states. Consequently, CRP may provide information

about systemic inflammation but is not specific to uterine fibroids. The relationship between

inflammatory processes and uterine fibroids has been investigated in previous studies, including research

examining inflammatory markers, fibroid risk, and symptomatic disease [6–8]. These investigations

provide a rationale for including CRP in biomarker studies of uterine fibroids. However, the presence of

an association between CRP and fibroids does not establish that systemic inflammation is a primary cause

of fibroid development.

In the present study, the reported CRP concentration was higher among women with fibroids than among

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controls. This difference requires interpretation alongside the clinical characteristics of both groups and

the methods used to exclude other inflammatory conditions. Although the manuscript reports excluding

women with chronic inflammatory conditions, additional information about relevant clinical factors

would strengthen the interpretation. The authors should also clarify whether CRP was measured using a

standard or high-sensitivity assay and report the laboratory method used. These details are important

when comparing the findings with other studies and assessing the potential value of CRP as a clinical

marker.

Vitamin D and Uterine Fibroid Biology

Vitamin D has been investigated in relation to uterine fibroid biology because of its potential effects on

cellular proliferation, differentiation, and pathways involved in extracellular matrix regulation.

Experimental research has explored whether vitamin D influences fibroid cell growth and fibrotic

signalling, including pathways associated with TGF-β1 [9,10]. These findings provide a biological basis

for investigating vitamin D status in women with uterine fibroids. Clinical research has also examined the

potential role of vitamin D supplementation in women with fibroids [11]. However, evidence concerning

a possible biological effect should be distinguished from evidence establishing a clinically meaningful

treatment benefit. A case-control comparison cannot determine whether vitamin D status influences the

development of fibroids, whether fibroids or associated factors influence vitamin D status, or whether the

observed relationship reflects other differences between the groups.

In the present study, the abstract and Table 1 report higher vitamin D levels in the fibroid group than in

controls, whereas the Results narrative states that vitamin D levels were lower among women with

fibroids. This contradiction is central to the interpretation of the study and must be resolved before a

conclusion can be drawn. The authors should verify the group labels, original laboratory values, units, and

statistical output. They should also clarify whether vitamin D supplementation, sun exposure, dietary

intake, body mass index, and menopausal status were assessed, because these factors may influence

vitamin D concentrations. Until the discrepancy is resolved, the study cannot reliably support the

conclusion that lower vitamin D levels are associated with uterine fibroids. Furthermore,

recommendations regarding vitamin D supplementation for fibroid prevention or treatment should not be

based solely on the findings of this study.

Relationship Between Biomarkers and Fibroid Severity

Investigating the relationship between biomarker concentrations and fibroid size or number may help

determine whether these measurements have potential value beyond distinguishing cases from controls.

Inflammatory and fibrotic pathways could plausibly be associated with differences in fibroid

characteristics. Previous research has explored the relationship between inflammation, vitamin D status,

and uterine fibroid biology [6–12]. Nevertheless, the clinical significance of these relationships depends

on the strength, consistency, and reproducibility of the observed associations.

The present manuscript reports positive associations between IL-6, TGF-β1, and CRP and fibroid

severity, while lower vitamin D levels are described as being associated with greater severity. However,

Table 2 does not provide interpretable correlation coefficients and corresponding p-values in its current

form. The reported values are presented as means and standard deviations despite the table headings

referring to correlation coefficients. Consequently, the stated relationships with fibroid size and number

cannot be independently evaluated.

Clinical Implications

The combined assessment of inflammatory, fibrotic, and nutritional biomarkers may be useful for

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exploring the biological heterogeneity of uterine fibroids. IL-6 and CRP may provide information about

inflammatory processes, while TGF-β1 is relevant to pathways involved in extracellular matrix

accumulation. Vitamin D has also attracted research interest because of its possible effects on fibroid cell

biology [1–12]. However, these potential roles do not establish that the biomarkers can diagnose fibroids,

predict disease progression, or guide treatment decisions.

Before clinical application can be considered, studies must demonstrate that biomarker measurements are

reproducible and provide meaningful information beyond established clinical assessment and imaging.

Their performance should be evaluated in appropriately designed studies with adequate sample sizes,

clearly defined outcomes, adjustment for relevant confounders, and independent validation. Longitudinal

research would be particularly valuable for determining whether biomarker levels are associated with

subsequent changes in fibroid size, symptom burden, or treatment response.

Strengths and Limitations

A strength of the present study is its comparative assessment of multiple biomarkers in women with

uterine fibroids and controls. Examining inflammatory, fibrotic, and nutritional factors together may

support a broader investigation of the biological processes associated with fibroid disease. The inclusion

of ultrasound-confirmed cases also provides a clinical basis for group classification, provided the

diagnostic criteria and procedures were applied consistently.

Several limitations should be acknowledged. The case-control design does not establish temporal

relationships or causality. The sample comprised 100 participants, with 50 in each group, which may limit

the precision and generalisability of the findings. Potential confounding factors, including menopausal

status, body mass index, vitamin D supplementation, and other determinants of inflammatory marker

concentrations, require clarification. In addition, the inconsistencies in the reported IL-6 and vitamin D

values and the lack of valid correlation statistics in Table 2 currently limit confidence in the interpretation.

These issues must be resolved through verification of the original data and statistical output rather than

editorial adjustment alone.

Conclusion

In summary, this study reinforces the significant role that inflammation and fibrosis play in the

development of uterine fibroids, as evidenced by the elevated levels of IL-6, TGF-β1, and CRP observed

in patients with fibroids. Additionally, the inverse relationship noted between vitamin D levels and the

severity of fibroids suggests that vitamin D deficiency may be a contributing factor to the progression of

these benign tumors. The results obtained from this investigation align with existing literature,

highlighting the potential therapeutic avenues offered by anti-inflammatory and antifibrotic strategies in

the management of fibroids. Therefore, targeting specific inflammatory pathways and optimizing vitamin

D levels may provide effective approaches for the prevention and treatment of uterine fibroids, warranting

further exploration in clinical practice.

Declaration

Conflict of Interest: The authors declare that they have no competing interests or conflicts of interest

related to this work.

Funding: Nil

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