Reproductive factors and risk of cardiovascular outcomes in women with ST-elevation myocardial infarction

Abstract

Background

There are many sex-specific factors affecting myocardial infarction (MI) outcomes in males and females. This study aimed to evaluate the relationship between reproductive factors and cardiovascular outcomes in women after ST-elevation MI.

Method

This retrospective cohort study was initiated in 2016–2017 at Chamran Hospital, Isfahan, Iran. One hundred eighty women with a diagnosis of ST-elevation MI were followed up for 3 years, and any occurrence of cardiovascular events (CVs) was recorded. All information regarding reproductive factors was recorded via questionnaire. This information was compared between women with cardiovascular events and women without adverse events using a sample t test, chi-square test, and multiple backward logistic regression analysis. SPSS version 24 was used to conduct all analyses.

Result

Sixty-four women with a mean age of 65.81 ± 13.14 years experienced CV events, and 116 women with a mean age of 65.51 ± 10.88 years did not experience CV events. A history of ischemic heart disease and diabetes mellitus were more prevalent in women with CV events (P = 0.024 and P = 0.019). After adjusting for ischemic heart disease and diabetes mellitus, oral contraceptive pill (OCP) usage was more prevalent in women with CV events than in women without CV events (60.9% vs. 40.4%, P = 0.008). There was a greater chance of CV events in women with OCP usage (OR = 3.546, P = 0.038) and a lower chance of CV events in women with greater age at menarche (OR = 0.630, P = 0.009) and longer breastfeeding duration (OR = 0.798, P = 0.041) according to multiple backward logistic regression models.

Conclusion

Based on this study, OCP consumption is a risk factor, while older age at menarche and longer duration of breastfeeding are protective factors for cardiovascular outcomes in women after STEMI.

Background

Coronary artery disease, specifically ST elevation myocardial infarction (STEMI), is a leading global cause of mortality in both sexes [1, 2]. Variations in the etiology, clinical manifestations, treatments, outcomes, and epidemiology of myocardial infarction (MI) arise from biological and socioenvironmental differences between women and men. Notably, the average age at first MI in women was 71.8 years, whereas it was 65 years for men. Additionally, women exhibit a higher death rate within the first year post-MI. Atypical chest pain and angina-equivalent symptoms, such as dyspnea, weakness, fatigue, and indigestion, are more prevalent in women. In the pathophysiology of MI, plaque erosion is more common in women, while plaque rupture is more likely in men. Women also experience certain MI complications at a higher rate, such as heart failure and susceptibility to cardiogenic shock after MI [3].

These sex-specific variations may stem from distinct risk factors. Psychosocial factors such as smoking, depression, anxiety, and stress, as well as variations in the prevalence of diabetes, hyperlipidemia, hypertension, metabolic syndrome, and chronic kidney disease, contribute to these differences [4].

Sex hormones, notably estrogen, play a significant role in explaining these sex disparities. Numerous studies have explored how estrogen impacts MI incidence, and the results support the preventive role of endogenous estrogen in cardiovascular events [5–7]. The effects of estrogen on the vascular endothelium lead to increased prostacyclin and nitric oxide levels, which induce vasodilation. Estrogen further promotes vasodilation by inhibiting mechanisms such as protein kinase C, calcium ions, and Rho kinase involved in smooth muscle contraction. Additionally, research indicates that estrogen influences lipid profiles and vascular inflammatory responses [8].

The effects of reproductive factors, which are influenced by sex hormones, on cardiovascular diseases have been extensively studied. A 2017 UK cohort study revealed associations between early menarche, early menopause, young age at first childbirth, abortion, stillbirth, and hysterectomy and an increased risk of cardiovascular diseases [9]. A case‒control study in Italy linked parity and an irregular menstrual cycle to an increased risk of MI [10].

Patients who have experienced MI are at risk of recurrence and other cardiovascular events [11]. Studies suggest that women with early-onset MI have a lower likelihood of early and late outcomes, such as cardiovascular death, MI recurrence, and stroke, than men [12, 13]. However, in older age groups, women face a greater risk of early and late outcomes after MI than men [14, 15].

Age-related differences in outcomes provide insight into the potential protective effect of estrogen on cardiovascular outcomes after MI and the role of reproductive factors. However, validated data on the association between reproductive factors and the risk of major adverse cardiovascular events after MI are scarce.

Limited studies suggest that women experiencing menopause later may have better outcomes following acute coronary syndrome (ACS), while both early and late menarche are associated with an increased risk of serious adverse cardiovascular events [16, 17].

The present study aimed to investigate the associations between reproductive factors (age at menarche, age at menopause, reproductive years, number of gravidities and parities, first parity age, and duration of breastfeeding) and major cardiovascular events following ST-Elevation MI. This research is crucial given the importance of preventing cardiovascular events post-MI and the insufficient studies on this relationship. Recognizing reproductive risk factors in women with ST-Elevation MI may lead to more effective preventive treatments, follow-ups, and improved clinical outcomes.

Method

This retrospective cohort study was initiated in 2016–2017 at Chamran Hospital in Isfahan, Iran. The inclusion criteria were women who were diagnosed with acute coronary syndrome, who showed ST segment elevation in two contiguous leads with cutoff points ≥ 1.5 mm in V2, V3, and ≥ 1 mm for other leads, or who had a new left bundle branch block on ECG. Additionally, participants had to exhibit an increase (exceeding the 99th percentile) and subsequent decrease in cardiac biomarkers during hospitalization, as evidenced by laboratory tests. The exclusion criteria included patients who were diagnosed with myocarditis, coronary artery spasm, or aortic dissection; who were unable to complete the questionnaire due to forgetfulness or patient death; and who lacked proper follow-up.

This study commenced after receiving ethical approval from the Research Ethics Committee of the School of Medicine - Isfahan University of Medical Sciences with the registration number IR.MUI.MED.REC.1400.248. Informed consent was obtained from all participants. Patients’ privacy was maintained through the anonymization of their information.

Trained personnel collected data during hospitalization through medical interviews, physical examinations, and paraclinical tests utilizing a validated questionnaire, calibrated instruments, and a standard protocol. The data included demographic information, cardiovascular risk factors, past medical history, vital signs upon arrival, location of MI, type of treatment, and the time interval between symptom onset and treatment.

Patient follow-up occurred annually over three years. A trained nurse contacted all patients to inquire about cardiovascular events, including nonfatal myocardial infarctions, nonfatal strokes, deaths from cardiac or noncardiac causes, rehospitalization for cardiac conditions, and revascularization. If any of these events occurred, patients were invited to Chamran Hospital and their related medical documents were reviewed by two expert cardiologists for a precise diagnosis, with death certificates evaluated in cases of patient death.

In 2022, a skilled nurse administered a questionnaire to collect information on reproductive factors such as age at menarche, menopausal status, age at menopause, history of hysterectomy and oophorectomy, oral contraceptive pill (OCP) usage, number of gravidities, number of parities, number of abortions, first pregnancy age, and breastfeeding duration.

Definitions were established for key terms. Natural menopause is defined as the permanent cessation of menstruation, determined retrospectively after a woman has experienced 12 months of amenorrhea without any other obvious pathologic or physiologic cause. Age at menopause was defined as the age at which the last menstruation occurred. Hysterectomy and hysterectomy-oophorectomy were classified as artificial menopause. The age at which a woman experiences her first menstruation is defined as the age at menarche. The time interval between the age of menarche and the age of menopause was considered the number of reproductive years. The total number of pregnancies of a woman is considered the gravid number, while the number of pregnancies extending beyond 20 weeks is considered the parity number, and fetal losses before 20 weeks of pregnancy are defined as abortion. The age at the first delivery of a child is defined as the first parity age. Breastfeeding duration is calculated as the total number of years that mothers breastfed their children. The history of OCP usage for more than two months was regarded as positive OCP usage. The history and length of OCP use were also recorded by month.

Dyslipidemia was considered if low-density lipoprotein cholesterol (LDL-C) was ≥ 130 mg/dL, total cholesterol (TC) was ≥ 200 mg/dL, triglycerides (TGs) were ≥ 150 mg/dL, or high-density lipoprotein cholesterol (HDL-C) was < 40 mg/dL in men or < 50 mg/dL in women. Diabetes mellitus (DM) was defined as a fasting blood glucose concentration ≥ 126 mg/dL or the use of antidiabetic agents. Participants with two blood pressure (BP) readings ≥ 140/90 mmHg or those taking antihypertensive drugs were classified as hypertensive. Body mass index (BMI) was defined as body weight (kg) divided by the square of body height (m²). Participants who used at least one cigarette per day were considered current smokers.

A positive cardiovascular event was defined as the presence of at least one of the following conditions:

1. Myocardial infarction, defined by typical chest pain lasting more than 30 min, ST elevation ≥ 0.1 mV in at least two contiguous electrocardiogram leads (≥ 0.2 mV in V2, V3), and an increase in serum cardiac biomarkers [18].

2. Stroke, defined as a rapid onset of focal neurological deficit persisting for at least 24 h with probable vascular etiology [19].

3. Cardiac death, encompassing all deaths with a cardiovascular etiology.

4. Rehospitalization due to unstable angina, heart failure, cardiac arrhythmia, and systemic embolism.

Quantitative data are presented as the mean ± standard deviation (SD) and were compared through independent sample t tests. Qualitative variables are presented as frequencies and percentages, and the chi-square test was used for comparisons. Univariate logistic regression adjusted for confounders was used to assess the associations between reproductive factors and cardiovascular events. Multiple backward logistic regression was subsequently employed to examine significant variables simultaneously. A significance threshold of P < 0.05 was applied. SPSS version 24 was used to conduct all analyses.

Results

A total of 180 women who were diagnosed with ST-elevation myocardial infarction participated in the study. Over the 3-year follow-up period, 64 patients (35.56%) experienced cardiovascular events, including 29 with revascularization, 6 with recurrent myocardial infarctions, 20 with hospitalizations due to cardiovascular causes, and 19 with cardiovascular deaths; no strokes were reported, and 10 women experienced 2 events. The mean age of patients with cardiovascular events was 65.81 ± 13.14 years, compared to 65.51 ± 10.88 years for those without events.

Table 1 presents baseline demographic characteristics categorized by cardiovascular event occurrence. A history of ischemic heart disease was more prevalent in women with cardiovascular events (29.7%) than in those without events (15.5%) (P = 0.024). Similarly, the prevalence of diabetes mellitus was greater in women with cardiovascular events (57.8%) than in those without events (39.7%) (P = 0.019). Other risk factors, including history of smoking, history of cardiovascular disease (CVD), history of hypertension, BMI, type of treatment, location of MI, admission vital signs, and left ventricular ejection fraction (LVEF) at discharge, were not significantly different between women with and without cardiovascular events.

Table 1.

Demographic and clinical characteristics of women with STEMI at presentation based on incident events during follow-up¹

Baseline characteristics	With event(n = 64)	Without event(n = 116)	Total (n = 180)	P value2
Age (year)	65.81 ± 13.14	65.51 ± 10.88	65.62 ± 11.70	0.872
History of smoking	4(6.3%)	2(1.7%)	6(3.3%)	0.188
History of CVD	5(7.8%)	6(5.2%)	11(6.1%)	0.524
History IHD	19(29.7%)	18(15.5%)	37(20.6%)	0.024
History of HTN	47(73.4%)	73(63.5%)	120(67%)	0.189
History of DM	37(57.8%)	46(39.7%)	83(46.1%)	0.019
History of DLP	28(43.8%)	39(33.6%)	67(37.2%)	0.2
BMI (kg/m2)	27.21 ± 4.33	27.23 ± 4.63	27.22 ± 4.51	0.980
Type of MI				0.124
Anterior	38(59.4%)	55(47.4%)	93(51.7%)	-
Others	26(40.6%)	61(52.6%)	87(48.3%)	-
MI Treatment				0.611
Primary PCI	41(64.1%)	84(72.4%)	125(69.4%)	-
Thrombolysis	18(28.1%)	26(22.4%)	44(24.4%)	-
CABG	2(3.1%)	3(2.6%)	5(2.8%)	-
Other	3(4.7%)	3(2.6%)	6(3.3%)	-
Time interval from symptom to treatment (hour)	18.52 ± 39.63	15.49 ± 31.94	16.59 ± 34.84	0.580
Last LVEF at discharge	38.42 ± 10.19	40.70 ± 10.97	39.84 ± 10.71	0.196
Heart rate	80.23 ± 13.70	82.41 ± 15.87	81.68 ± 15.17	0.423
SBP (mmHg)	128.11 ± 28.44	129.41 ± 25.07	128.95 ± 26.24	0.751

Abbreviations: IHD: Ischemic Heart Disease, HTN: Hypertension, DM: Diabetes Mellitus, DLP: Dyslipidemia, BMI: Body Mass Index, MI: Myocardial Infarction, PCI: Percutaneous Coronary Intervention, CABG: Coronary Artery Bypass Graft, LVEF: Left Ventricular Ejection Fraction, SBP: Systolic Blood Pressure

¹Quantitative data are presented as the mean ± standard deviation, and qualitative variables are presented as frequencies and percentages

²Sample t test for quantitative variables and chi-square test for qualitative variables. A P value < 0/05 was considered significant

Table 2 summarizes the reproductive characteristics of women with ST-elevation myocardial infarction based on the incidence of events during follow-up. This comparison showed that patients with cardiovascular events had a significantly greater history of OCP use than patients without cardiovascular events (P = 0.008). Specifically, 60.9% of women with cardiovascular events had a history of OCP use, while 40.4% of women without events had used OCP in the past. No statistically significant differences were found for other reproductive factors, including age at menarche, age at menopause, reproductive years, natural or surgical menopause, number of gravidities, number of parities, number of abortions, breastfeeding duration, OCP use duration, or first parity age. After adjusting for a history of diabetes mellitus and ischemic heart disease, women with a history of OCP use were found to be at a greater risk of cardiovascular events (OR = 2.141, P = 0.019). No significant associations were detected for other reproductive factors.

Table 2.

Comparison of reproductive characteristics of women with STEMI based on event occurrence during follow-up.¹

Reproductive Factors2	With event	Without event	Total	P value3
Age at menarche (year)	13.41 ± 1.94	13.28 ± 2.054	13.32 ± 2.01	0.679
Age at menopause (year)	48.16 ± 5.33	49.04 ± 5.81	48.73 ± 5.64	0.346
Reproductive years (year)	34.93 ± 5.48	35.87 ± 6.31	35.53 ± 6.02	0.351
Menopause occurrence	58(92.1%)	107(92.2%)	165(92.2%)	0.999
Type of menopause				0.803
Natural	50(86.2%)	95(88.8%)	145(87.9%)	-
Artificial	8(13.8%)	12(11.2%)	20(12.1%)	-
Positive OCP use	39(60.9%)	46(40.4%)	85(47.8%)	0.008
OCP use duration (month)	40.63 ± 61.70	28.93 ± 57.62	33.11 ± 59.21	0.206
Number of gravidities	6.63 ± 2.97	6.83 ± 3.63	6.76 ± 3.40	0.704
Number of parities	5.98 ± 2.64	5.85 ± 3.14	5.90 ± 9.97	0.778
Number of abortions	0.63 ± 1.08	0.98 ± 1.50	0.86 ± 1.37	0.094
First parity age	18.48 ± 4.38	18.11 ± 3.70	18.24 ± 3.96	0.564
Breast feeding duration (year)	9.92 ± 5.60	9.99 ± 6.06	9.97 ± 5.88	0.940
Age at menopause				0.417
≤44	14(24.6%)	19(18.4%)	33(20.6%)	-
44–55	39(68.4%)	71(68.9%)	110(68.8%)	-
≥56	4(7%)	13(12.6%)	17(10.6%)	-
Age at menarche				0.856
≤10	4(6.6%)	10(8.9%)	14(8.1%)	-
11–14	42(68.9%)	76(67.9%)	118(68.2%)	-
≥15	15(24.6%)	26(23.2%)	41(23.7%)	-
Age at menopause in Natural	48.20 ± 5.23	49.38 ± 5.85	48.97 ± 5.65	0.240
Age at menopause in Artificial	47.88 ± 6.31	46.42 ± 4.91	47.00 ± 5.40	0.568

Abbreviations: OCP: oral contraceptive pill

¹Quantitative data are presented as the mean ± standard deviation, and qualitative variables are presented as frequencies and percentages

²To reduce recall bias, some uncertain data regarding reproductive factors were considered as missing data. The variables with the most missing data were age at menarche and age at menopause, with 7 and 5 missing data respectively. The remaining variables had between 0 to 3 missing data

³Sample t test for quantitative variables and chi-square test for qualitative variables. A P value < 0/05 was considered significant

Table 3 presents multiple backward logistic regression for the examination of significant variables simultaneously to adjust the effects of the variables on each other and to independently assess the effects of each reproductive factor on cardiovascular events. Notably, OCP use was associated with a greater risk of cardiovascular events. Women with a history of OCP use were 3.54 times more likely to experience cardiovascular events than women without OCP use (OR = 3.546, P = 0.038). Additionally, older age at menarche was found to have a protective effect on cardiovascular events (OR = 0.630, P = 0.009), and a longer duration of breastfeeding was associated with a lower risk of cardiovascular events (OR = 0.798, P = 0.041).

Table 3.

The odds ratio of reproductive factors and baseline characteristics for cardiovascular events after adjusting for important variables

Variables	Odds Ratio	95% Confidence Interval	P value1
Age at menarche	0.630	(0.445, 0.891)	0.009
OCP use	3.546	(1.071, 11.744)	0.038
First parity age	1.120	(0.951, 1.320)	0.174
Number of gravidities	1.531	(0.970, 2.415)	0.067
Number of Abortion	0.552	(0.288, 1.057)	0.073
Breast feeding duration	0.798	(0.644, 0.990)	0.041
History IHD	6.345	(1.411, 28.540)	0.016
History of HTN	6.986	(1.489, 32.774)	0.014
Last LVEF at discharge	1.030	(0.970, 1.093)	0.333
Heart rate	0.964	(0.925, 1.005)	0.084
SBP	0.981	(0.958, 1.004)	0.104
Time interval from symptom to treatment	1.014	(0.993, 1.036)	0.19
MI Treatment			0.054
PCI to thrombolysis	0.226	(0.005, 10.484)	0.447
PCI to other	1.557	(0.032, 76.322)	0.823

Abbreviations: IHD: Ischemic Heart Disease, HTN: Hypertension, MI: Myocardial Infarction, PCI: Percutaneous Coronary Intervention, LVEF: Left Ventricular Ejection Fraction, SBP: Systolic Blood Pressure

¹ Using multiple backward logistic regression. A P value < 0/05 was considered significant

Table 4 categorizes the incidence of different cardiovascular events based on the type of intervention each patient received after STEMI. According to the analysis performed, there is no statistically significant association between the incidence of cardiovascular events and the type of intervention (P value > 0.05).

Table 4.

Stratifying the cardiovascular events based on the intervention patients received after ST-elevation myocardial infarction

events		Treatment				Total	P value1
		PCI (n = 125)	Thrombolysis (n = 44)	CABG (n = 5)	Other2 (n = 6)
revascularization	yes	17(13.6%)	11(25%)	0(0%)	1(16.7%)	29 (16.1%)	0.249
	no	108(86.4%)	33(75%)	5(100%)	5(83.3%)	151 (83.9%)
Cardiovascular death	yes	13(10.4%)	3(6.8%)	1(20%)	2(33.3%)	19(10.6%)	0.159
	no	112 (89.6%)	41(93.2%)	4(80%)	4(66.7%)	161(89.4%)
Rehospitalization	yes	13(10.4%)	6(13.6%)	1(20%)	0(0%)	20(11.1%)	0.615
	no	112(89.6%)	38(86.4%)	4(80%)	6(100%)	160(88.9%)
Stroke	yes	0(0%)	0(0%)	0(0%)	0(0%)	0(0%)	-
	no	125(100%)	44(100%)	5(100%)	6(100%)	180(100%)
Recurrent MI	yes	4(3.2%)	2(4.5%)	0	0	6(3.3%)	0.762
	no	121(69.5%)	42(24.1%)	5(2.9%)	6(3.4%)	174(96.7%)

Abbreviations: PCI: Percutaneous Coronary Intervention, CABG: Coronary Artery Bypass Graft, MI: Myocardial Infarction

¹ Using chi-square test. A P value < 0/05 was considered significant

² Patent coronary artery that needed no intervention or patients with medical treatment

Discussion

In this study, a 3-year follow-up of women with STEMI revealed an association between OCP use and a greater risk of cardiovascular events. In addition, this study revealed an association between each year in which the age of menarche increased and each year in which the duration of breastfeeding increased with a lower risk of cardiovascular events in women with STEMI. Conversely, no significant associations were found between cardiovascular events and age of menopause, reproductive years, number of gravidities and parities, abortion, OCP duration, or first parity age.

Few studies have explored the associations between reproductive factors and cardiovascular outcomes postmyocardial infarction. Julie J. Lee and colleagues, in a 6-year follow-up of 648 women with coronary angiography, identified associations between both early and late menarche age and adverse cardiovascular outcomes, whereas our study showed the protective effect of late menarche age on cardiovascular outcomes [17]. In contrast to this study, a cohort study in Japan showed that early or late menarche is not associated with risk of mortality from coronary heart diseases [20]. Some prior investigations have linked early age at menarche to an increased risk of cardiovascular events in the general population [21, 22]. Although our focus was on women with STEMI, our results align with these findings. It should be noted that the age of menarche depends on environmental conditions and may vary according to the socio-economic conditions of society in different countries [23]. Consequently, the different results regarding the effects of age at menarche on cardiovascular disease may be due to this factor.

The protective effect of breastfeeding against cardiovascular disease has been established in various studies. A 2015 systematic review revealed that breastfeeding is associated with a lower incidence of diabetes mellitus, hypertension, hyperlipidemia, and cardiovascular disease [24]. In another study, during 4,705,160 person-years of follow-up, a reduction in mortality from cardiovascular diseases was observed in patients with a history of breastfeeding for more than 3 months, compared to those with a history of breastfeeding for less than 3 months [25]. Our study, adjusting for important variables, reaffirmed the protective role of breastfeeding on cardiovascular outcomes in women with STEMI. This could be attributed to the impact of breastfeeding on reducing visceral fat and the hormonal effects on blood pressure, as discussed in the American Journal of Epidemiology [26].

A notable finding was the association between OCP use and cardiovascular events in women with STEMI during the 3-year follow-up. Women who experienced cardiovascular events were more likely to have a history of OCP use (60.9%) than were those without such events (40.4%). Although the relationship between OCP use and cardiovascular outcomes post-STEMI has not been extensively studied, existing research suggests an increased risk of cardiovascular disease in women using oral contraceptives. Chrisandra L. Shufelt and colleagues demonstrated elevated risks of myocardial infarction and venous thromboembolism among current users of first- and second-generation OCPs [27]. Similarly, a 2021 study in Nigeria highlighted a short-term atherogenic risk increase associated with combined oral contraceptive consumption in women [28]. Contrary to the results of our study, a 10-year follow-up study of women with IHD found that a history of OCP use was associated with reduced mortality in these patients. However, after adjusting the results, this association was no longer significant [29]. This discrepancy in results could be due to the different types of OCPs and their varying hormonal compositions such as progestin type and estrogen dose [30]. Further research is warranted to comprehensively understand the potential advantages and disadvantages of prior OCP use.

Strengths and limitations

The strengths of this study include its adherence to internationally accepted methodologies and quality control protocols and its unique population of women with STEMI. The evaluation of reproductive factors and cardiovascular outcomes in this specific population adds a distinctive dimension to the research landscape. Simultaneous multivariate analysis of critical variables further strengthened the study.

However, limitations include a reliance on self-reported historical data, potentially introducing recall bias. Efforts were made to mitigate this bias by treating uncertain responses as missing data. The study’s small sample size and short follow-up period are additional constraints, emphasizing the need for larger, longer-term investigations. Future research should explore female-specific risk factors and cardiovascular outcomes in the context of STEMI, particularly to comprehensively assess the implications of OCP use.

Conclusion

In conclusion, our study revealed that OCP consumption is a risk factor for cardiovascular events in a three-year follow-up of women with STEMI, while older age at menarche and a longer duration of breastfeeding are protective factors against cardiovascular events in women after STEMI. These results can contribute to the identification of women at greater risk for recurrent cardiovascular events. This knowledge can guide clinical professionals towards more follow-ups and stringent preventive interventions to manage the recurrence of cardiovascular events. Further studies with larger samples and longer follow-up periods are necessary to investigate the female-specific risk factors for cardiovascular outcomes after STEMI in more detail and to shed light on the differential effects of OCP use.

Author contributions

AS designed the study. SR was responsible for data acquisition. SR and AS executed the study. MJ analyzed the data. MJ and MS interpreted the data. Data verification has been done by MS. SR drafted the manuscript. All authors revised the manuscript. All authors read and approved the final manuscript.

Funding

There is no funding for the project.

Data availability

Any data related to the study can be provided upon reasonable request.

Declarations

Ethics approval

This study commenced after receiving ethical approval from the Research Ethics Committee of the School of Medicine - Isfahan University of Medical Sciences with the registration number IR.MUI.MED.REC.1400.248. Informed written consent was obtained from all patients at the beginning of the study.

Competing interests

The authors declare no competing interests.