Factors affecting women scientists’ retention and progress in STEM fields in the UAE: A cross-sectional study

Introduction

The representation of women working in professions related to science, technology, engineering, and mathematics (STEM) is disproportionate to the percentages of those graduating from STEM fields. Worldwide, multiple studies documented an increase in the number of women receiving postgraduate degrees but a relatively static representation of women in faculty positions in STEM fields (Casad et al. 2022; Roper 2019). The World Economic Forum reports a persistent gender gap in STEM fields; for example, women graduate in information and communication technology represent 1.7% compared to 8.2% of men graduates. Similarly, women represent only 6.6% of engineering and manufacturing graduates compared to 24.6% for men (“World Economic Forum” 2022).

A study from Massachusetts Institute of Technology (MIT) published in 1999 showed that senior women faculty felt discrimination in salary, awards and resources in spite of the same qualification and competency. Subsequently, the MIT initiated recommendations to increase representations of women in STEM. Despite their efforts, the increase in recruitments were not sustainable after few years (Lawler 2006). Available evidence further demonstrates the prevalence of gender bias in STEM fields, documenting its adverse effects on key professional outcomes (Moss-Racusin et al. 2012; Steinpreis, Anders, and Ritzke 1999; Reuben, Sapienza, and Zingales 2014; Quadlin 2018; Sarsons 2017; Robyn et al. 2018). A double-blind RCT indicated that faculty significantly favored male applicants for a lab manager position, offering them higher salaries and more mentoring opportunities (Moss-Racusin et al. 2012). This bias extends across STEM, hindering women in hiring callbacks (Quadlin 2018), tenure decisions due to undervalues research (Sarsons 2017), and success in grant peer review (Robyn et al. 2018).

The disparity is postulated to be related to gender stereotyping impacting recruitment and career advancement, limited social networks and existing work climates in academia (Casad et al. 2022). It was also shown that social exclusion from men dominated fields resulted in fewer career opportunities for women (Cyr et al. 2021). In the UAE, similar social and gender factors play a role in the lower representation of women in workforce in STEM fields (Houjeir et al. 2019).

Two recent review articles addressing women in STEM in the UAE highlighted some of the challenges in the field. In one review, it was shown that male-dominance in fields like engineering and difficulty in having a clear promotion track resulted in women to leave engineering and pursuing other fields of work (Alzaabi, Ramirez-Garcia, and Moyano 2021). Social factors and family demand on women in addition to some societal gender-biases are attributable to lower number of women working in STEM (Patterson, Varadarajan, and Salim 2021).

In the US, the National Institute of Health (NIH) and the National Science Foundation (NSF) supported grants to investigate gender disparity in STEM careers. One notable initiative is the NSF-funded ADVANCE interventions (Casad et al. 2022). It included interventions to enhance recruitment of women in STEM, improve academic climate and develop mentoring and networking (Casad et al. 2022). Higher education institutions can benefit from the evidence based research work and the proposed StratEGIC Toolkit developed by some investigators to enhance women representation in STEM. Using this toolkit, institutions can implement structural changes that support women’s advancement in STEM fields based on evidence-based guidelines (Laursen & Austin 2014). In a recent study, investigators used comics and text-only tweets to increase awareness about underrepresentation and stereotypical biases about women in STEM (Freedman et al. 2022).

In the UAE, multiple government initiatives are in place to encourage students to enroll to STEM fields. However, there is limited research looking into challenges facing women working in STEM fields in the UAE (Patterson, Varadarajan, and Salim 2021).

In the current study, we aim at exploring these challenges to better understand the current situation. This will help in providing recommendations that allow better retention of women in STEM fields.

Methods

To achieve the aim of this research, a cross-sectional study design was adopted. A validated questionnaire was used to explore and assess the factors affecting women scientists’ retention and progress in STEM fields in the UAE (Rentsch & Steel 1992; “Canadian Nuclear Safety Commission (CNSC) Annual Report 2019–20”; Hopkins 2002). The questionnaire (The survey actually consisted of 44 questions). Of these:

- see extended data 1) was divided into three sections: demographic, attitudes questions, and the Andrews and Withey job satisfaction questionnaire. The questionnaire was piloted from August-September 2022 and a reliability analysis was carried out on three subscales namely: the attitude, satisfaction, retention subscales using Cronbach’s alpha (α). Overall, Cronbach’s alpha for the three subscales indicated the questionnaire reached good reliability (α = 0.88). In details, the attitude subscale was found to have questionable reliability (9 items (Q23.1 to Q23.9); α = .63), the satisfaction subscale indicated acceptable reliability (8 items (Q28 to Q35); α = .78), and the retention subscale reached excellent reliability (7 items (Q36 to Q41); α = .92). Most items appeared to be worthy of retention, resulting in a decrease in the alpha if deleted from the subscale. The one exception to this was item Q23.1 in attitude subscale “It is important to take action to increase the involvement of women and girls in STEM fields.”, which would increase the alpha to α = 0.73 if deleted. Therefore, removal of this item was considered. Furthermore, one question in the retention subscale “Please rate the importance of Paid leadership development related to your workplace (7 stars are the highest score and 1 star is the lowest score)” was removed during pilot phase validity due to difficulty in comprehending the question by the respondents.

Results

Participants’ characteristics

A total of 165 participants (comprising 15% UAE nationals) took part in the survey with majority being males (62%). Most of the participants were between the age of 40-49 years (35%) ( Table 1). The majority (77%) were married with more than half (53%) of the participants reporting having 1-3 children under the age of 18. Most of the respondents had a doctorate (76%), were employed (92%), work in academic establishments (78%), and/or had more than 20 years of work experience (44%). Finally, 82% of the participants claimed to be the main economic provider or principal financial supporter of their respective families.

Table 1. Characteristics of participants (N=165).

Characteristic	All, N (%)	Females, N (%)	Males, N (%)
Gender
Female	62 (38%)	-	-
Male	103 (62%)	-	-
Age
20-29 years old	8 (4.8%)	8 (13%)	0 (0%)
30-39 years old	37 (22%)	18 (29%)	19 (18%)
40-49 years old	57 (35%)	24 (39%)	33 (32%)
50-59 years old	39 (24%)	10 (16%)	29 (28%)
60-64 years old	9 (5.5%)	1 (1.6%)	8 (7.8%)
> 65 years old	15 (9.1%)	1 (1.6%)	14 (14%)
Marital status
Married	127 (77%)	31 (50%)	96 (93%)
Unmarried	38 (23%)	32 (50%)	7 (7%)
Highest education
Bachelor’s degree	10 (6.1%)	8 (13%)	2 (1.9%)
Master’s degree	30 (18%)	19 (31%)	11 (11%)
Doctorate degree	125 (76%)	35 (56%)	90 (87%)
Nationality
UAE	24 (15%)	15 (25%)	9 (9.3%)
Other Asians	58 (37%)	24 (40%)	34 (35%)
Africa	20 (13%)	7 (12%)	13 (13%)
America/Europe/Australia	55 (35%)	14 (23%)	41 (42%)
Employment status
Employed	151 (92%)	49 (79%)	102 (99%)
Unemployed	14 (8.5%)	13 (21%)	1 (1.0%)
Employer
College or university	127 (78%)	37 (62%)	90 (87%)
Federal, or government setting	20 (12%)	10 (17%)	10 (10%)
Others	16 (10%)	15 (21%)	3 (3%)
Years of employment in STEM
<5 years	17 (10%)	13 (21%)	4 (3.9%)
5-10 years	28 (17%)	16 (26%)	12 (12%)
11-15 years	28 (17%)	13 (21%)	15 (15%)
16-20 years	19 (12%)	8 (13%)	11 (11%)
>20 years	73 (44%)	12 (19%)	61 (59%)
Home main income source
Self	130 (82%)	36 (60%)	94 (96%)
Others	28 (18%)	24 (40%)	4 (4%)

Factors influencing women to be in STEM Most women (77%) were influenced to join STEM driven by a personal interest or passion ( Figure 1). 18% of respondents were influenced by family and 16% chose a STEM field for a better work environment. Role models in STEM only influenced the choice in 13% of respondents.

Figure 1. Most influencing factors to be in STEM among women.

Feeling about current STEM job

Generally, a higher percentage of women (45% versus 23% for men) considered quitting their current STEM job in the last 2-3 years ( Figure 2). Overall, men were most likely to feel better in their current STEM job than women ( Figure 2). Specifically, more men, than women, reported that “they feel their current job matches their educational background and skills” (94% versus 76%), that “they feel they were growing professionally” (67% versus 42%), that “they see a path for to advance their career at their institution” (70% versus 54%), and that “they were equitably fairly rewarded” (54% versus 38%) among others.

Figure 2. How participants feel about their current STEM job by gender.

Gender inequality and the participants’ experience

Of the respondents, 47% of women and 28% of men believed that there is a lack of gender equality in STEM ( Figure 3). Moreover, a significantly higher proportion of women reported experiencing gender inequality (44% women compared to 8% men). Females were about sixteen times more likely to experience gender inequality than men (aOR=15.8, 95% CI=6.08-45.7, p<0.001). Similarly, those working in the academic sector, including college and universities, had three times the odds of experiencing gender inequality as compared to those working in other sectors (aOR=3.38, 95% CI=1.15-11.3, p=0.035) ( Table 2).

Figure 3. Gender inequality and the experience of women and men.

Table 2. Association between demographics and gender inequality experience.

Factors	cOR	95% CI	p-value	aOR	95% CI	p-value
Age
< 40	1.00			1.00
≥ 40	1.11	0.49, 2.70	0.800	2.00	0.75, 5.71	0.200
Gender
Male	1.00			1.00
Female	9.16	3.96, 23.4	<0.001	15.8	6.08, 45.7	<0.001
Education
Bachelor’s degree	1.00			1.00
Postgraduate	1.08	0.26, 7.40	>0.900	1.45	0.26, 11.4	0.700
Employer
Others	1.00			1.00
College or university	1.41	0.56, 4.06	0.500	3.38	1.15, 11.3	0.035

Attitude towards challenges facing women in STEM

Overall, women expressed negative attitudes regarding challenges facing them in STEM ( Figure 4). Majority of both women (82%) and men (62%) believed that “the caregiver stereotype forces women to choose more often than men between time intensive careers and having a family.” Additionally, majority of women also believed that “the historical bias against women’s ability in science that is culturally widespread” (63%), that “cultural stereotypes of women scientists still exist” (58%), that “leadership opportunities for men often come with more resources” (53%), that “organizations expect women to be more qualified than men for the same positions” (53%), and that “women lack access to mentors and networking opportunities compared to men” (52%). Furthermore, 35% of the women believed that “the glass ceiling in their institutions prevents women and minorities from reaching the highest levels in STEM.” In contrast, only a minority of men (16%) believed “leadership opportunities for men often come with more resources”, and only 15% believed that “organizations expect women to be more qualified than men for the same positions”, and only 9% of men believed that “women lack access to mentors and networking opportunities compared to men”. Lastly, a relatively comparable percentage of men (24%), in contrast to 35% women, believed a glass ceiling effect exist in STEM.

Figure 4. Attitude toward challenges facing women in STEM in the UAE.

Workplace challenges and experiences in STEM

More women, than men, reported having experienced gender-based unfair treatment from direct manager and/or peers (35% versus 3%), that they had observed/experienced seeing women face lack of career progression in the STEM field (39% versus 13%), and that they had observed women being treated unfairly at work based on gender (45% versus 8%). Forty-four percent and sixty percent of women and men respectively said that their CEOs supports women in leadership ( Figure 5). Although 42% of women and 30% of men said their organizations had diversity inclusion-focused committee (DIFC), only 26% and 18% respectively said the DIFCs had been instrumental in promoting leadership roles for women ( Figure 6).

Figure 5. Workplace challenges and experiences faced by women and men in STEM in the UAE.

Figure 6. Presence and functioning of organizational diversity and inclusion-focused committee (DIFC) at participants’ workplaces.

Support needed to thrive in STEM

Among women, the most common support needed to thrive in STEM were respectful/proper interactions with manager (58%), healthcare benefits (55%) and flexible schedules (48%) among others ( Figure 7). While for men, the most common support needed to thrive in STEM were healthcare benefits (59%), flexible schedules (48%), and respectful/ proper interactions with manager (47%) among others ( Figure 7). Thematic analysis of the open-ended responses (Q22) on barriers to women’s advancement revealed several key themes, which are summarized in Table 3.

Figure 7. Support needed by females and males to thrive in STEM.

Table 3. Themes from Reported Barriers to Women’s Advancement in STEM (Q22 Open-Ended Responses).

Theme	Definition	Supporting Quotes
1. Gender Bias in Hiring, Pay, and Promotion	Systemic discrimination where women receive unequal treatment in hiring, compensation, promotion, or leadership access.	“His salary was higher”, HR replied that he is a man, he has to support the family.” “Men promoted or given responsibility when CV of the female employee is clearly superior.”
2. Motherhood and Family Responsibilities as Career Barriers	Women’s roles as mothers and caregivers negatively affect their career progress or continuity.	“Female pharmacists, might request later maternity leave.”‌ “Career gaps due to childbearing" do not affect men.”‌
3. Lack of Institutional Support and Flexibility	Inadequate policies or accommodations for women’s needs, such as flexible hours, childcare, or post-maternity reintegration.	“Inflexible workloads, giving women more opportunities to have part-time hours, online meetings, etc.”‌ “Lack of support after maternity leave.”‌
4. Cultural and Social Norms Reinforcing Gender Roles	Societal and workplace norms that reinforce traditional female roles and diminish professional credibility or opportunities.	“Women are questioned about their commitment if they want both a family and a career.”‌ “Cultural need for women to manage household and childcare.”‌
5. Exclusion from Networks, Resources, and Fair Processes	Limited access to support, networks, or fair processes due to male-dominated environments, favoritism, or underrepresentation.	“Female faculty did not receive lab space,male did.”‌ “Not a single woman in university management.”‌

When asked about their recommendations to the employer and government on how to improve the employment and career environment for women scientists, respondents recommended improving the work environment for women scientists by introducing flexible working hours, remote work options, and part-time roles to support work-life balance. They emphasized the need for better childcare support, including on-site daycare and extended paid maternity leave, along with policies that facilitate reintegration after childbirth. Calls were also made for equitable hiring, promotion, and leadership opportunities, more mentorship and female role models, and increased recognition through fair pay and dedicated research funding. Institutional reforms, such as clear gender equality policies and accountability measures, were seen as essential. An analysis of open-ended responses regarding reasons for leaving science careers early (Q43) identified five primary themes, detailed in Table 4.

Table 4. Thematic Analysis - Women Leaving Science Careers Early (Q43 Open-Ended Responses).

Theme	Definition	Supporting Quotes
1. Family Responsibilities and Caregiving Burden	The overwhelming burden of caregiving duties (e.g., children, elderly, spouse) often forces women to prioritize home over career.	“Family commitments. Family responsibilities. Care for children and the elderly.”
2. Lack of Work-Life Balance and Flexibility	Rigid work hours, long shifts, and inability to adjust roles to accommodate personal life lead to burnout and early career exit.	“Inflexibility for work time. Workload. Long hours and heavy work responsibilities.”
3. Poor Workplace Culture and Mental Health Strain	Toxic work environments, stress, mental exhaustion, and lack of appreciation contribute to resignation.	“Poor work environment… they choose mental health over money and career advancement.”
4. Gender Discrimination and Lack of Career Progression	Inequity in promotions, lack of recognition, and systemic bias demoralize women and block advancement.	“Lack of promotion. Working hard but suppressed by male colleagues. Bias and discrimination.”
5. Structural and Policy Gaps (e.g., parental leave, support systems)	Lack of institutional support such as maternity leave, reintegration policies, and job security for women scientists.	“Insufficient parental leave policies. Difficult to relaunch career after maternity. Lack of stable positions.”

Discussion

In this cross-sectional analysis of adult men and women who either graduated or were working in the STEM fields in multiple institutions of higher education across the United Arab Emirates, we found that more women reported to experience gender-based unfair treatment from direct managers and/or peers, lacked access to mentors and networking opportunities compared with their male counterparts, and organizations provided more resources to men for leadership opportunities while asking women to be more qualified for the same positions. Furthermore, more men than women reported to agree that their current job matched with their educational background and skills, and more women than men considered the possibility of quitting the job in STEM in the last 2-3 years. For retention in the STEM, women rated flexible work schedule, proper interactions with direct manager, and tenure promotional opportunities higher than men.

Our results are consistent with the findings of earlier studies demonstrating the prevalence of gender bias in science disciplines, and how this bias may affect the professional hiring, promotion, mentoring, and funding opportunities (Moss-Racusin et al. 2012; Steinpreis, Anders, and Ritzke 1999; Reuben, Sapienza, and Zingales 2014). The findings of a double blind RCT indicated that male applicants for a lab manager position, evaluated by both male and female science faculty, were significantly more likely to be hired, receive a higher annual salary, and to get more mentoring opportunities than the female applicants (Moss-Racusin et al. 2012). Similar results were reported by others across diverse fields showing that job applicants with female names were less likely to be called by employers (Quadlin 2018), woman faculty member was also less likely to receive tenure because her research contributions are often undervalued (Sarsons 2017), and male applicants were favored over females for peer review in grant fundings (Robyn et al. 2018).

Approximately 40% of women in our study considered leaving STEM, and these results are in line with a recent publication showing comparable numbers (Conrad, Abdallah, and Ross 2021). Many factors have been reported to affect the women retention in the STEM which include but not limited to work life balance or flexibility, unequal standards for men and women, stress and gender discrimination (Conrad, Abdallah, and Ross 2021; Blackburn 2017; Smith and Gayles 2017). The women in our study rated flexible work schedule much higher than men to stay in their respective jobs. The lack of flexibility regarding family commitments has been recognized as a factor motivating women to pursue careers outside of STEM (Conrad, Abdallah, and Ross 2021). Other factors rated higher by the women in our study were the support systems in terms of clear communications with direct managers and promotional opportunities. The results of a study of junior biomedical researchers in the United States comprising of 92 women and 127 men who applied for early-career grant fundings showed that junior faculty women received significantly less start-up support compared with men from their institutes (Sege, Nykiel-Bub, and Selk 2015). The lack of these support systems could influence the persistence of women in their chosen careers (Conrad, Abdallah, and Ross 2021).

There is also evidence that these specific challenges faced by women during their professional careers in STEM may even persist during the periods of college or university education, and can have career-impacting effects. Previous research has identified various factors, including low level of self-efficacy despite being equally prepared (Koch et al. 2022), inadequate support from family, school and faculty (Tandrayen-Ragoobur and Gokulsing 2021), as well as other psychosocial and non-cognitive elements (Ortiz-Martínez et al. 2023) that might contribute to women showing lower persistence rates than men when it comes to completing a STEM degree. The findings also suggest that gender gap in STEM education is not an isolated issue but rather a systemic challenge.

Several strategies have been proposed to address the gender disparity in STEM areas using various approaches, including efforts related to attraction, access, and retention (García-Peñalvo et al. 2019). The framework proposed by Eddy and Brownell (2016) identified observable inequalities in performance and engagement as factors contributing to gender gaps. Makarem and Wang (2019) highlighted various coping strategies women generally employ, including conforming to expectations, engaging in impression management, and taking proactive steps to assert themselves and overcome obstacles, to counter the challenges related to predominantly male-dominated environments, including gendered organizational culture and stereotypes. Furthermore, the underrepresentation of women in STEM filed is partly due to systemic obstacles to the recruitment, retention and promotion, and institutes should consider implementing strategies to change the structures and climates of workplaces, and to create a more inclusive and supportive environment for women pursuing STEM careers (DeAro, Bird, and Mitchell-Ryan 2019).

Figure 9. Support needed to thrive in STEM – Males.

Evidence-based measures can be implemented to address socio-cultural and structural challenges. For example, institutional reforms to support work-life balance, providing flexible work arrangements and on-site childcare have shown to mitigate the disproportionate caregiving burdens faced by women (Allen 2014; Cech & Blair-Loy 2019). Structured mentoring and sponsorship programs that connect women STEM professionals with senior leaders have proven particularly effective enhancing both retention and career advancement opportunities (Dennehy & Dasgupta 2017; García-Silva et al., 2025). To address the gender disparities in hiring and promotion, mandatory bias training programs have been successful especially in male-dominated subfields like engineering (Williams et al. 2016). Finally, establishing transparent accountability mechanisms through public reporting on gender equity metrics (e.g., compensation gaps, leadership representation), can help to track progress and maintain institutional accountability (Kalev et al. 2006).

The international organizations have emphasized on critical significance of addressing the gender disparity in higher education, specifically within the STEM. The United Nations’ Sustainable Development Goal 4, with a specific focus on target 4.3, calls for equal access to tertiary education, including universities, for both women and men (Heleta & Bagus 2020). Data from the Organization for Economic Co-operation and Development (OECD) show a significant improvement in the fields of natural sciences, mathematics, and statistics, achieving a state of gender parity. However, this achievement contrasts with the persistence of a gender gap in fields like engineering and information and communication technologies. The OECD also highlights the importance of eradicating stereotypes, implementing gender balance policies across various academic disciplines, and actively cultivating an inclusive environment to encourage greater female participation in traditionally male-dominated fields (Organisation for Economic Co-operation and Development 2021; OECD 2021).

A recent study looking to challenges impacting advancing in leadership positions in higher education in the UAE, demonstrate similar challenges to women in STEM fields. It highlights the deficiencies in current policies and gender biases that hinders women’s progression in these roles. Similarly, it illustrates the need for training and initiative to ensure work-life balance (Al-Naqbi & Aderibigbe 2024).

Beyond the specific context of the UAE, our findings resonate strongly with the global research landscape, revealing a troubling universality in gender bias within STEM. Although our study sample is uniquely comprised of individuals from varied cultural backgrounds working in the UAE, the patterns we observe such as biases in competence evaluation and barriers to equitable opportunity closely echo those documented in North America (al. 2012; report 2024a, 2024b Aug 5), and East Asia (UNDP 2024). The convergence of evidence across different cultural and geographical settings highlights that the mechanisms perpetuating gender bias in STEM are not confined by national or cultural boundaries; rather, they are ingrained within the very structures and prevailing norms of the STEM fields themselves. Consequently, our study provides a vital microcosm that reinforces the global nature of this challenge, suggesting that effective solutions must target these universal, field-specific biases alongside localized cultural considerations.

Up to our knowledge, this study is the first to investigate retention and progression challenges encountered by women in STEM fields in the UAE. It examines this issue from the perspectives of both male and female individuals in STEM fields across various institutes within the UAE. Employing a validated questionnaire, ensures a systematic exploration of pertinent factors and allow for benchmarking with other countries in the globe. Furthermore, the piloting process and calculation of Cronbach’s alpha underscore the methodological rigor and reliability of the study. The study has some limitations. One is that it lacks data on the social inclusion of women in STEM, a critical aspect for comprehending broader socio-cultural influences on their experiences in the field. But this is important to know, since social factors can have a big impact on women’s experiences in STEM. For example, research has shown that stereotypes can make women feel less engaged and less like they fit in at work. So, not having information about social inclusion makes it harder to understand the full picture. Another limitation is that the study doesn’t look at differences between different types of STEM fields, like engineering and science. Research has shown that these fields can have different challenges and working environments. So, not accounting for these differences could make the findings less specific. We recommend conducting longitudinal research tracking the career trajectories of women in STEM fields over time to provide valuable insights into the factors influencing their career decisions and outcomes. Understanding how these factors evolve over time can inform strategies for improving retention and promoting gender diversity in STEM and can be insightful for policy makers. Another limitation is that the study did not reach the initially calculated sample size (384), primarily due to the sensitivity of the topic, which may affect the representativeness and generalizability of the findings.

Conclusions

Our study presents the first UAE-specific quantitative analysis of factors influencing the retention and career progression of women in STEM. These findings highlight critical gaps in organizational support, with fewer women reporting the presence of diversity and inclusion committees and perceiving them as effective. Work-life balance challenges, along with inadequate access to mentorship and professional networks further impede career advancement and impact retention. Our results advocate for UAE institutions to strengthen diversity initiatives, implement flexible work policies, and expand structured mentorship programs. By addressing these gaps with targeted, evidence-based interventions, organizations and policymakers can make meaningful progress toward improving gender equity and supporting the sustained participation of women in STEM fields.

Author contributions

Conceptualization, A. R, L. Z, S. A, H. A, R. F, P.S; methodology, A. Z, JN, S.A; validation, A. R, J.N; analysis, A. Z, S.A, A. S, A.S.A; X.X.; investigation, X.X.; resources, X.X.; data curation, X.X.; writing—original draft preparation, S. A, A.R, J. N, A.A. writing—review and editing, all authors. All authors have read and agreed to the published version of the manuscript.

Ethics and consent

The study was approved by the Social Sciences Ethics Committee (IRB) of the United Arab Emirates University with approval number ERSC_2022_1527 on 25/10/2022. A detailed information sheet about the purpose of the study was distributed to participants, and written informed consent was obtained from each participant before inclusion in the study. Involvement of human participants compiled with the ethical standards set forth in the Declaration of Helsinki.