Testosterone to Oestradiol Ratio: A Significant Indicator for Prediction of Coronary Artery Disease in Males

By Hafsa Aziz¹, Muhammad Anwar², Muhammad Qaiser Alam Khan², Muhammad Younas², Zujaja Hina Haroon³, Uzma Naeem⁴

Affiliations

1. Department of Chemical Pathology, National University of Medical Sciences, Rawalpindi, Pakistan
2. Department of Chemical Pathology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan
3. Department of Chemical Pathology, Combined Military Hospital, Peshawar, Pakistan
4. Department of Chemical Pathology, Combined Military Hospital, Rawalpindi, Pakistan

doi: 10.29271/jcpsp.2025.07.814

ABSTRACT
Objective: To determine the association of serum testosterone / oestradiol ratio (T/E2) with coronary artery disease (CAD) in males.
Study Design: A comparative cross-sectional study.
Place and Duration of the Study: Department of Chemical Pathology, Armed Forces Institute of Pathology, in collaboration with Armed Forces Institute of Cardiology, Rawalpindi, Pakistan, from February 2023 to January 2024.
Methodology: Plasma testosterone and oestradiol concentrations were determined in the blood samples of 300 males. Serum T/E2 ratio was associated with history and baseline characteristics. CAD markers according to serum T/E2 quartiles were compared to study the relation of T/E2 ratio with disease progression. T/E2, C-reactive protein (CRP), and total cholesterol were compared by one-way ANOVA test in groups divided based on the cardiac calcium score.
Results: Higher calcium scores were connected with greater amounts of CRP (low: 10.0 mg/L, moderate: 16.5 mg/L, and high: 33.0 mg/L, p <0.001), oestradiol (median: 165.0 pmol/L, IQR: 212.0–14.0), and less testosterone (median: 12.0 nmol/L, IQR: 18.5–6.0). T/E2 ratios were found to play a role in coronary risk, as they decreased a lot as the calcium score increased (from 0.98 in the low group to 0.40 in the high group, p <0.001). The findings also highlighted that different biochemical patterns correspond with the link between T/E2 ratios and the risk of heart disease.
Conclusion: Men with a T/E2 ratio lower than 1.41 had more calcified plaque (median calcium score: 100.0, IQR: 410.0–50.0) and higher levels of systemic inflammation (median CRP: 22.0 mg/L, IQR: 59.0–9.0). Consequently, a T/E2 ratio below 1.41 can be used as a simple and inexpensive marker to predict major heart events in men.

Key Words: Body mass index, Cardiac calcium score, Coronary artery disease, CT angiography, Myocardial infarction, Testosterone to oestradiol ratio.

INTRODUCTION

The illness known as coronary artery disease (CAD) is caused by the accumulation of atherosclerotic plaque in the coronary artery wall, which narrows the arteries and causes acute coronary syndrome symptoms.¹ The primary cause of death worldwide is cardiovascular disease (CVD).² An increased risk of CVD is caused by a number of variables, such as diabetes, obesity, dyslipidaemia (abnormal blood cholesterol levels), hypertension (high blood pressure), and ageing. According to the epidemiological research, men may be more susceptible to CVD than women.³

Given that, the number of people affected by CVD has increased over the past ten years, and the disease's impact is growing significantly. Approximately, 18.6 million deaths worldwide were attributed to CVD, with 49.2% of those cases (9.14 million) being linked to CAD.⁴ Vascular health has been demonstrated to be impacted both directly and indirectly by testosterone (T) and oestrogen-related steroid hormones, such as 17β oestradiol (E2).⁵ According to the epidemiological research, CAD is more of a concern for men than for women.⁶

A significant correlation between low testosterone to oestro-gen ratios (T/E2) in males with cardiovascular event risk when compared to peers with normal ratios has been previously observed.⁷ The T/E2 ratio might be an indicator of aromatase activity, providing information about the variables influencing vascular inflammation in men. Compared to researching the effects of testosterone, oestrogen, and related hormones separately, examining this pathway may offer more comprehensive knowledge.⁸ There are several direct and indirect impacts of testosterone and oestrogen-related steroid hormones, such as 17β oestradiol, on artery health that have been recognised.⁹ A low ratio of testosterone to oestradiol (T/E2) may make males more susceptible to atherosclerosis. Although the effects of both hormones are positive, E2 is usually thought to be more protective. A decreased T/E2 ratio may increase the risk of CAD by causing greater inflammation and more susceptible plaques.¹⁰

The purpose of this research was to determine the clinical relevance of the T/E2 ratio in predicting men's risk of CAD. Through an examination of the correlation between this hormone ratio and the occurrence and severity of CAD, this study aimed to ascertain if the T/E2 ratio can be a useful biomarker for identifying men who are more likely to acquire or experience severe cardiovascular events.

METHODOLOGY

This comparative cross-sectional study was conducted at the Department of Chemical Pathology, Armed Forces Institute of Pathology, in collaboration with the Armed Forces Institute of Cardiology, Rawalpindi, Pakistan. Plasma testosterone and oestradiol concentrations were determined in blood samples of 300 males through immunoassay at the Department of Chemical Pathology, Armed Forces Institute of Pathology, Rawalpindi, Pakistan, from February 2023 to January 2024. Ethical approval was taken from the Institutional Review Board of both participating centres (IRB. No: 2773; Dated: 27 July 2024). Serum T/E2 ratio was associated with history and baseline characteristics. A sample size of 300 patients was calculated using the WHO calculator, keeping the margin of error at 5%, a confidence level at 95%, power of test at 80%, respectively.¹¹

All male patients (40-60 years) presenting to the Institute of Cardiology for coronary CT angiography were included in the study. Patients on hormone replacement therapy, diagnosed with testosterone-producing tumours, diabetics and patients on insulin therapy, hypertensive patients, patients on lipid- lowering medicines, patients with a history of angioplasty or previous myocardial infarction, and acute and chronic inflammatory conditions were excluded from the study.

CAD markers according to serum T/E2 quartiles were compared to study relation of T/E2 ratio with disease progression. T/E2, CRP, and total cholesterol were compared by one-way Anova in groups divided based on the coronary calcium score. The serum T/E2 ratio was calculated by dividing the testosterone / oestradiol by using the formula.

The cardiac calcium score on CT angiography was used to stratify CAD patients into three different groups. It was divided into tertiles as low (0-100), moderate (101-400), and severe (400), depending on the level and extent of coronary plaque inflammation, represented through cardiac and oestradiol levels, which were analysed by chemiluminescence on an automated calcium scoring system. Serum total cholesterol was measured using an automated analyzer. Serum testosterone was assessed using an immunoassay analyzer. CRP was performed through immunoassay on an automated chemistry analyzer. Quality control was assured by using two levels of laboratory control samples verified by the Westgard rules.

The statistical analysis for this study was conducted using the Statistical Package for the Social Sciences (SPSS) version 26. The normality of the data was assessed using the Shapiro-Wilk test. The frequencies and percentages were calculated for qualitative variables. Since the quantitative variables, including CRP, total cholesterol, and T/E2 ratio, were not normally distributed, their medians and interquartile ranges (IQR) were calculated for descriptive statistics. To compare the differences in these variables across the three calcium score groups (low, moderate, and high), as well as across the three T/E2 ratio groups (low, normal, and high), the Kruskal-Wallis test was employed. For pairwise comparisons among the three T/E2 ratio groups (Low, Normal, and High), Dunn’s Post-Hoc test was employed due to the non- parametric nature of the data. The p-value of less than 0.05 was considered statistically significant.

RESULTS

A total of 300 male participants were included in this study.  The median age of participants was 46 (52.00-41.00) years. The baseline characteristics of study population are shown in Table I.

Table II presents a comparison of CRP, total cholesterol, T/E2 ratio, and calcium scores across both calcium score groups (low, moderate, and high) and T/E2 ratio groups (low <1.41, normal 1.41–1.89, and high >1.89). CRP levels increased significantly with rising calcium scores (p <0.001), indicating a strong association between inflammation and subclinical CAD. Similarly, CRP levels decreased significantly across increasing T/E2 ratio groups (p <0.001).

Table  I:  Baseline  characteristics  of  study  variables  (n  =  300).

Variables	Median, IQR
Age (years)	46.00 (52.00-41.00)
BMI (kg/m2)	27.00 (31.00-23.00)
CRP (mg/L)	15.00 (55.00-6.00)
Total cholesterol (mmol/L)	4.00 (6.00-2.00)
Testosterone	12.00 (18.50-6.00)
Oestradiol	165.00 (212.00-14.00)
Calcium score	100.00 (375.00-50.00)
	n (%)
BMI
Normal (18.5-24.9)	82 (27.3%)
Overweight (25-29.9)	127 (42.3%)
Obese (>30)	91 (30.3%)
Smoking
Smoker	140 (46.7%)
Non-Smoker	160 (53.3%)
Hypertension
Yes	135 (45.0%)
No	165 (55.0%)
Diabetes
Yes	103 (34.3%)
No	197 (65.7%)
T/E2 Ratio groups
Low (<1.41)	236 (78.7%)
Normal (1.41-1.89)	25 (8.3%)
High (>1.89)	39 (13.0%)
CA score
Normal	137 (45.7%)
Moderate	102 (34.0%)
Severe	61 (20.3%

Table II: Comparison of biochemical markers across calcium score and T/E2 ratio groups.

Biochemical markers	Calcium score groups				T/E2 ratio groups
	Low (n = 137)	Moderate (n = 102)	High (n = 61)	p-value	Low (n = 236)	Normal (n = 25)	High (n = 39)	p-value
CRP (mg/L)	10.00 (25.00-5.00)	16.50 (59.00-6.00)	33.00 (61.50-13.00)	<0.001	22.00 (59.00-9.00)	5.00 (15.00-3.10)	8.00 (9.00-2.20)	<0.001
Total cholesterol (mmol/L)	4.00 (5.20-2.05)	3.10 (5.30-1.90)	5.60 (7.12-2.00)	0.003	4.20 (6.30-1.90)	3.00 (4.00-2.00)	4.00 (5.20-3.00)	0.134
T/E2 ratio	0.98 (1.75-0.49)	0.60 (1.05-0.49)	0.40 (0.63-0.21)	<0.001	—	—	—	—
Calcium score	—	—	—	—	100.00 (410.00-50.00)	50.00 (100.00-10.00)	50.00 (90.00-0.00)	<0.001

Table III: Pairwise comparisons of key variables among calcium score and T/E2 ratio groups (n = 300).

Variables	Group types	(I) Group	(J) Group	p-value
CRP (mg/L)	Calcium score groups	Low	Moderate	0.008
		Low	High	<0.001
		Moderate	High	0.370
	T/E2 ratio groups	High	Normal	1.000
		High	Low	<0.001
		Normal	Low	<0.001
Total cholesterol	Calcium score groups	Moderate	Low	0.329
		Moderate	High	0.002
		Low	High	0.082
T/E2 ratio	Calcium score groups	High	Moderate	0.001
		High	Low	<0.001
		Moderate	Low	0.003
Calcium score	T/E2 ratio groups	High	Normal	1.000
		High	Low	<0.001
		Normal	Low	0.002

Total cholesterol varied significantly among calcium score groups (p = 0.003) but did not differ significantly among T/E2 ratio groups (p = 0.134). The T/E2 ratio itself declined markedly with increasing calcium scores (p <0.001), while calcium scores rose significantly in groups with lower T/E2 ratios (p <0.001), highlighting a reciprocal relationship. These findings underscore the interconnected roles of lipid meta-bolism, sex hormone balance, and systemic inflammation in cardiovascular risk stratification.

Table III presents pairwise comparisons of key variables—CRP, total cholesterol, T/E2 ratio, and calcium score—across calcium score groups (low, moderate, and high) and T/E2 ratio groups (low, normal, and high). In the calcium score groups, CRP levels showed significant differences between low and moderate (p = 0.008) and low and high groups (p <0.001), indicating an upward trend in CRP with increasing calcium scores, while no significant difference was noted between moderate and high groups (p = 0.370). Total cholesterol significantly differed between moderate and high groups (p = 0.002), with no significant difference between moderate vs. low (p = 0.329) and low vs. high (p = 0.082). The T/E2 ratio showed significant differences across all calcium score group comparisons: High vs. moderate (p = 0.001), high vs. low (p <0.001), and moderate vs. low (p = 0.003), indicating a strong inverse relationship with calcium scores.

In the T/E2 ratio groups, CRP levels were significantly higher in the low group compared to both the high (p <0.001) and normal (p <0.001) groups, while no difference was found between the high and normal groups (p = 1.000). Similarly, calcium scores were significantly higher in the low T/E2 group compared to the high (p <0.001) and normal (p = 0.002), groups with no significant difference between high and normal groups (p = 1.000). These findings suggest that lower T/E2 ratios are strongly associated with elevated CRP levels and higher coronary calcium scores, highlighting their potential link to systemic inflammation and subclinical athero-sclerosis.

DISCUSSION

Oestrogen and testosterone both play significant biochemical roles in either gender.¹² There is an ongoing debate on the connection between male and female sex hormones and the cardiovascular system. According to an in vitro research, high local concentrations of 17β oestradiol prevent LDL oxidation and lower the production of cholesterol oester.¹³ Predicting the risk of developing any major acute cardio-vascular event (MACE) in the future is an area of great interest in preventive cardiology. Late onset of CVD in women has been attributed to protective effects of oestrogen during reproductive years, while in males, low levels of testosterone have been associated with increased risk of atherosclerotic manifestations.¹⁴ A significant association was found between low serum T/E2 ratio when comparing individuals with elevated levels of systemic inflammation, plaque size, and cardiovascular event risk to individuals with normal ratios.¹⁵ Although prior observational study data did not indicate a positive correlation between testosterone and CAD to establish that elevated levels of this androgen could be a risk factor, they did imply that reduced testosterone levels may be present in CAD patients.¹⁶

A study conducted by Wu and von Eckardstein showed that testosterone levels were frequently lower in males with CAD, raising the possibility of a connection between low testosterone and the onset or advancement of CAD.¹⁷ From the present results, it was noted that higher calcium scores were associated with considerably higher CRP levels, indicating that CRP is a good indicator of systemic inflammation and the severity of CAD. There are similar to the results of Ridker et al. highlighting CRP as a predictor of cardiovascular events, as patients with subclinical athero-sclerosis had higher CRP levels. The current investigation supports these findings by associating increased CRP with coronary calcification.¹⁸ These results show an inverse relation between CAD and testosterone, which is similar to the findings of Borges, stating that men's cardiovascular events and testosterone levels were found to be inversely related in a meta-analysis. Comparing males receiving testosterone replacement therapy (TRT) to those receiving a placebo, the results indicate an 18% lower risk of cardio-vascular events.¹⁹

Oestradiol's function in men is still debatable, in contrast to testosterone. Higher levels of oestradiol in men may be related to worse cardiovascular outcomes, especially when coupled with hormonal abnormalities, according to Aryan et al. The current study shows a direct correlation between the severity of CAD and oestradiol levels.²⁰ Khanna et al. discovered that elevated visceral fat and systemic inflam-mation, the two risk variables for CAD, were associated with a low T/E2 ratio. These findings are supported and expanded upon in the current study to include hormonal dysregulation and coronary calcification.²¹

Improved understanding of the mechanisms that cause inflammation will make it possible to identify more specific molecular biomarkers of atherosclerosis. Long-term, double-blind, randomised, and placebo-controlled trials should be conducted to assess the effects of aromatase blockers on cardiovascular disease with low testosterone and oestradiol levels. This could be extremely useful in advancing the understanding of atherosclerosis.

CONCLUSION

A significant association was noted between the T/E2 ratio and the level of CAD. The relationship between hormonal balance and the severity of CAD is supported by the mean T/E2 ratio's decline from normal to severe.

ETHICAL  APPROVAL:
Ethical approval was taken from the Institutional Review Board of both participating centres (IRB. No: 2773; Dated: 27 July 2024).

PATIENTS’ CONSENT:
Informed consent was obtained from the participants.

COMPETING  INTEREST:
The authors declared no conflict of interest.

AUTHORS’ CONTRIBUTION:
HA: Design, acquisition of the data, data analysis, and writing of the manuscript.
MA: Data analysis, review, and interpretation.
MQAK, UN: Review.
MY: Review and interpretation.
ZHH: Conception and design.
All authors approved the final version of the manuscript to be published.

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