Introduction

Medical advances allow many organs and tissues to be transplanted more easily (Marinho et al., 2018). Organ donation and transplantation have significantly improved the quality of people's lives, positively impacting their physical, emotional, and social relationships and professional performance (Can, 2017). However, despite the significant progress in surgical techniques for organ donation, there still exists a large gap between the demand and supply of organs worldwide (Bortz et al., 2015; Marinho et al., 2018; Rezapour et al., 2023). The slow growth rate in organ donation has become a severe challenge in developing countries (Shah, 2018). According to a report from Iran's Ministry of Health, Treatment, and Medical Education, there are approximately 25,000 people on the transplant waiting list, and about ten new cases are added daily (Khoshravesh et al., 2021). The decision to sign the organ donation card is influenced by various individual and sociocultural factors (O'Carroll et al., 2016; Vijayalakshmi et al., 2016).

More studies are needed to determine the factors influencing the reluctance to donate organs. However, it is essential to provide reliable information about organ donation to the public in order to encourage greater participation in organ donation programs and address the shortage of organs (Taş et al., 2022). The literature review shows that people's attitudes toward organ donation vary based on socioeconomic factors (Başal, 2015; Can, 2017) and psychosocial factors (Ríos et al., 2018), as well as personal and religious–cultural conditions (Ríos et al., 2018; Uzuntarla, 2019).

The studies show that spirituality and religion are two significant factors affecting a person's attitude toward organ donation (Başal, 2015; Khoshravesh et al., 2021). Since spirituality and religious beliefs influence how people view life and shape the underlying feelings and thoughts that drive many behaviors, they can extensively impact decisions related to organ donation (Berzelak et al., 2019; Uzuntarla, 2019). Cultural norms also play a significant role in people's views of death and, consequently, their feelings about organ donation. The most common religious conviction behind the refusal of organ donation is the preservation of bodily integrity for the afterlife (Tarabeih et al., 2022).

In addition to the physical, emotional, and social dimensions of the holistic care approach embraced by nurses, the spiritual dimension should also be prioritized as an inseparable aspect of holistic care (Çınar & Eti Aslan, 2017). A person's spiritual health guides their spiritual feelings in decision-making (Taş et al., 2022). Therefore, spiritually healthy individuals can establish strong positive relationships with others and find meaning in their lives by connecting to a higher power (Ekşi & Kardaş, 2017).

Spirituality is defined as accepting meaning, purpose, and value in life (Bortz et al., 2015; İsmailoğlu et al., 2019). SWB involves the search for meaning, purpose, and understanding of a higher power upon which life is based (Ekşi & Kardaş, 2017). The spiritual dimension becomes particularly highlighted in critical situations when individuals face threats in life, such as illness, stress, fear of death, questioning the meaning of life, and loss of hope (Çınar & Eti Aslan, 2017). A sense of purpose in life is a mechanism that underscores the significance of voluntary activities like organ donation (Bortz et al., 2015). Therefore, individuals' SWB is expected to influence their attitudes toward organ donation. Thus, determining the relationship between people's SWB and their attitude toward organ donation is crucial for increasing their willingness to donate organs (Alcan & Abdulkadir, 2021).

On the other hand, healthcare professionals should consider several cultural and spiritual factors when working with Iranian organ donors. Religious beliefs are significant in Iranian culture, and many Iranians adhere to the Shia branch of Islam. Healthcare professionals should be aware of and respectful of these religious beliefs, which may impact a person's decision to donate or receive organs. For example, some Shia Muslims believe that organ donation is permissible, while others may be concerned about the body's sanctity and the afterlife (Parsa et al., 2019). Family relationships; Family relationships are highly valued in Iranian culture, and decisions about organ donation may involve consultation with extended family members. Healthcare professionals should be sensitive to these cultural norms and include family members in discussions about organ donation when appropriate (Attum et al., 2018; Doerry et al., 2022). Communication style; Iranian culture highly values politeness and indirect communication. Healthcare professionals should be aware of these cultural norms and use appropriate communication styles when discussing organ donation with Iranian donors and their families. Trust in healthcare professionals is an essential factor in Iranian culture, and many Iranians may be hesitant to donate organs if they feel that their wishes will not be respected or that their organs may be used for purposes other than transplantation. Healthcare professionals should take steps to build trust with Iranian donors and ensure that they feel informed and empowered to make decisions about organ donation (Abbasi et al., 2020; Parsa et al., 2019). Stigma and misconceptions; There may be stigma and misconceptions surrounding organ donation in Iranian culture, which can impact a person's decision to donate or receive organs. Healthcare professionals should be aware of these cultural beliefs and provide accurate information about organ donation to help dispel any myths or misconceptions (Kiani et al., 2018; Li et al., 2019). Healthcare professionals should approach organ donation discussions with Iranian donors and their families with sensitivity, respect, and cultural competence to ensure that their spiritual and cultural beliefs are considered and addressed.

The concept of SWB is rooted in individuals' culture and religious background. Additionally, there is a need for an accurate scale to measure this concept among people in different countries, such as Iran, where Islam is the official religion. Numerous scales have been developed to assess SWB. One of the most common scales used is the SWBS, which was initially developed and psychometrically evaluated by Paloutzian and Ellison (1982). This scale consists of two dimensions: religious well-being and existential well-being, which, respectively, measure the person's relationship with God, as well as life satisfaction, spirituality, and purpose (Paloutzian & Ellison, 1982). Another scale is the SWB questionnaire designed by Gomez and Fisher (2003), which evaluates four aspects of SWB: personal, social, environmental, and transcendental (Gomez & Fisher, 2003). The Spiritual Orientation Inventory (Elkins et al., 1988) is another scale based on existential and valuable issues (Elkins et al., 1988). Finally, the JAREL Spiritual Well-Being Scale is another scale for measuring SWB that includes personal questions about participants, others, and God (Hungelmann et al., 1996).

Considering that the SWBS is one of the most widely used scales for evaluating SWB, which reports good validity and reliability (Dehshiri et al., 2013), it was deemed the most appropriate scale for the current study. Given the increasing importance of the field of spirituality and its connection with the concept of health, as well as the significance of organ donation and the impact of SWB on people's attitudes toward organ donation, further psychometric evaluations should be conducted on the SWBS in different communities and groups (Sharif Nia et al., 2018). Considering that the concept of SWB is influenced by culture and beliefs, accurate measurement of this concept requires a scale that fits the Iranian-Islamic context. In the present study, the psychometric evaluation of the Persian version of the SWBS was performed for some reasons; first, the SWBS is a widely used tool for assessing SWB, an essential aspect of overall well-being. SWB refers to a person's sense of meaning, purpose, and connection to something greater than themselves, which can provide a sense of comfort and support during difficult times (Sharif-Nia et al., 2023); second, organ donation is a complex issue that can have significant spiritual and cultural implications for both donors and recipients. In Iranian culture, for example, strong religious and cultural beliefs surround organ donation, which can impact a person's decision to donate or receive organs. Validating the SWBS in Iranian organ donors can help healthcare professionals better understand the spiritual and cultural factors influencing organ donation decisions (Parsa et al., 2019). Third, validating the SWBS in Iranian organ donors can also help healthcare professionals identify potential barriers to organ donation and develop strategies to overcome them. For example, suppose a significant number of Iranian organ donors report low levels of SWB. In that case, healthcare professionals may need to provide additional support and resources to help these donors cope with organ donation's emotional and spiritual aspects (Kiani et al., 2018). Overall, validating the SWBS in Iranian organ donors can provide valuable insights into the spiritual and cultural factors that influence organ donation decisions and help healthcare professionals support organ donors and recipients more effectively. This study aimed to examine the psychometric characteristics of the Persian version of the SWBS among potential organ donors in Iran.

Methods

Design

This cross-sectional, methodological study was conducted in 2022. The minimum sample size for conducting the factor analysis is equal to 5–10 times more than the number of the items of the intended instrument (Soleimani et. al., 2016). Using convenience sampling, 316 community members willing to donate organs participated in this study. The participants were enrolled between July and October 2022. The inclusion criteria included individuals who could read and write in Persian. Some general exclusion criteria that could be considered are:

  1. (a)

    Age The SWBS is typically used with adult populations, and some studies may exclude individuals under 18.

  2. (b)

    Mental health conditions Individuals with severe mental health conditions, such as schizophrenia or severe depression, may not be appropriate candidates for completing the SWBS.

  3. (c)

    Cognitive impairments Individuals with cognitive impairments, such as dementia or intellectual disability, may have difficulty understanding and completing the SWBS.

  4. (d)

    Language barriers The SWBS has been translated into various languages. However, individuals who do not speak the language in which the instrument is administered may not be appropriate candidates for completing the SWBS.

  5. (e)

    Lack of spiritual or religious beliefs The SWBS is designed to measure spiritual well-being, so individuals with no spiritual or religious beliefs may not be appropriate candidates for completing the instrument.

It is important to note that exclusion criteria should be chosen carefully to ensure that the study results are valid and reliable. Additionally, researchers should consider ethical considerations and ensure the exclusion criteria are not discriminatory or biased.

Measurement

Participants were asked to complete the Persian version of the SWBS. Data collection consisted of two parts. The first part included demographic information, and the second included the standard SWBS. Demographic information included age, gender, marital status, occupation, and education level. The second part included the Persian version of the SWBS.

Permission was obtained from Dr. Paloutzian to use this scale. The Persian version of the SWBS consists of two subscales: religious well-being (10 items) and existential well-being (10 items). The religious well-being subscale assesses one’s relationship with God, while the existential well-being subscale evaluates one’s sense of life purpose and life satisfaction. The SWBS is scored on a six-point Likert-type scale ranging from 1 (completely disagree) to 6 (completely agree), with a reversed scoring method used for negative questions (items 1, 2, 5, 6, 9, 12, 13, 16, and 18). The range of scores for each subscale is between 10 and 60. Higher scores indicated a higher level of religious or existential well-being (Paloutzian & Ellison, 1982).

The World Health Organization protocol was employed to translate and adapt the English SWBS into Persian. A forward–backward translation technique was applied, involving two English–Persian translators who independently translated the SWBS. An expert panel, comprising the authors of the present paper and the two translators, assessed the two translated questionnaires and produced a single Persian version. Subsequently, a Persian–English translator back-translated the Persian SWBS into English (World Health Organization, 2009).

Construct Validity Assessment

To evaluate the construct validity of the Persian SWBS, an exploratory factor analysis (EFA) was conducted using maximum likelihood (ML) estimation, followed by a Promax rotation in SPSS27 (SPSS Inc., Chicago, IL, USA). The suitability of the research sample and factor analysis model was assessed using the Kaiser–Meyer–Olkin (KMO) test and Bartlett’s test of sphericity. Bootstrap sampling was used to estimate 95% confidence intervals for the KMO index by Factor software. The number of factors was determined based on Kaiser's criterion (eigenvalues and > 1). Items with a factor loading of 0.3 or higher were considered appropriate (Harrington, 2009). The factor structure derived from the EFA was then examined using confirmatory factor analysis (CFA) conducted in AMOS27. Model fit was evaluated using several fit indices, including the chi-square goodness-of-fit index per degree of freedom (CMIN /DF < 3), root mean square error of approximation (RMSEA < 0.08), goodness-of-fit index (GFI > . 90), comparative fit index (CFI > 0.90), incremental fit index (IFI > 0.90), and Tucker–Lewis’s index (TLI > 0.90) (Coughlan et al., 2008).

Reliability Assessment

The internal consistency of the Persian version of SWBS was evaluated using Cronbach’s alpha (α) and McDonald's omega (Ω). Values of α and Ω greater than 0.7 were considered acceptable.

Invariance Analysis

Configural, metric, and scalar invariance for sex (male vs. female) was tested by a series of increasingly constrained models from no constraints (same structure in both groups), equal factor loadings between groups (metric invariance), equal factor loadings and equal intercepts (scalar invariance), and equal loadings, intercepts and means between groups. Invariance was assumed for either no significant Δχ2 between nested models or ΔCFI < 0.01 and or ΔRMSEA < 0.01 (Cheung & Rensvold, 2002; Marôco, 2014). The JASP0.17.1.0 was used for invariance analysis.

Ethical Considerations

This study was supported by the Student Research Committee of Mazandaran University of Medical Sciences and Ethics Committee (IR.MAZUMS.REC.1401.555). Informed consent was obtained from all participants, who were informed about the study's aims and procedures. Participants were assured that participation was voluntary and that their information would be kept confidential.

Results

The majority of the participants were female (62%) and single (58.9%), with an average age of 30.29 (SD = 10.34), ranging from 18 to 61 years. 54.1% of the participants had a bachelor's degree, and 90.5% were employed. Table 1 provides details of participants' demographic characteristics.

Table 1 Participant demographic characteristics (316)
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Construct Validity

The results of the KMO test (0.919, 95% CI: 0.905 to 0.932) and Bartlett's test (p < 0.001, Bartlett value = 2760.92) indicated that the sample was adequate for factor analysis. After Promax rotation in EFA, four items were removed, resulting in a total number of sixteen items in the SWBS, which were classified into three factors: higher power with (seven items), the meaning of life (five items), and sense of life (four items). These three factors explained 50.23% of the total variance in spiritual well-being among individuals willing to donate organs. The first factor accounted for 26.18% of the variance, the second for 13.18%, and the third for 10.87%. Table 2 provides the details results of the factor analysis.

Table 2 The result of EFA on the three factors of SWBS (n = 158)
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During the CFA, the model derived from EFA was tested (Fig. 1). The results of the model fit indices showed that the model is fit and acceptable (X2 = 230.69, DF = 99, CMIN/DF = 2.330, RMSEA = 0.065, GFI = 0.915, CFI = 0.951, IFI = 0.952, TLI = 0.941). The internal consistency analysis demonstrated good reliability for three factors (Table 2).

Fig. 1
figure 1

The CFA measurement model of SWBS among Iranian population

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Invariance Analysis for Gender

The results for the analysis of invariance for sex are given in Table 3. The configure invariance model fits well for both sexes (CFI = 0.927, RMSEA = 0.078). Also, metric and scaler testing for the three-factor structure were invariant (Table 3).

Table 3 Invariance analysis for sex
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Discussion

This study aimed to assess the psychometric properties of the Persian version of the SWBS among Iranians who are potential organ donors. The results of the EFA revealed the presence of three independent factors, which accounted for a total variance of 50.23%. The SWBS is a widely used scale for measuring an individual's SWB. It consists of two subscales, namely religious well-being and existential well-being. Participants rate their level of agreement or disagreement with various statements on the scale. When applied to the general population of potential organ donors, the SWBS can provide insight into the spiritual aspects of their decision and its potential impact on their well-being (Sharif Nia et al., 2018). However, it is essential to note that the SWBS is not scale solely designed to assess attitudes toward organ donation. It is a more comprehensive scale of SWBS, and this study represents its first development and validation in Iran.

Studies examining the factor structure of the SWBS have been conducted from 1998 to 2022. Based on a systematic review study, the researchers reported the presence of two to five latent factors for this scale, and the range of explained variance was between 35.6 and 71.4% (Sharif-Nia et al., 2023). Similar to other studies, in the present investigation, three factors were extracted.

In the current study, the first factor extracted was higher power. In the context of the SWBS, a higher power typically refers to a belief in a transcendent or divine force greater than oneself. It is often associated with religious or spiritual frameworks and can take various forms depending on an individual's beliefs. The notion of a higher power is central to many religious traditions and spiritual practices (Lewis, 2008). It represents a source of meaning, purpose, guidance, and support for individuals seeking a deeper connection with something beyond the material world. This belief in a higher power can play a significant role in shaping an individual's SWB. For individuals identified with a particular religious tradition, their higher power may be associated with a specific deity or divine figure from their religious teachings. In this case, SWB may involve cultivating a relationship with that deity, following religious rituals and practices, and deriving a sense of comfort, meaning, and fulfillment from their faith (Lalajants, 2018).

The second factor extracted was the meaning of life. The meaning of life is a profound and complex concept often explored within the realm of SWB. It encompasses questions about human existence's purpose, significance, and ultimate value., In the context of SWB, the meaning of life is closely related to one's sense of purpose, connection, and fulfillment on a deeper spiritual level (Pellengahr, 2018). Different philosophical, religious, and spiritual traditions offer various perspectives on the meaning of life. Some belief systems propose that the meaning of life is derived from a higher power or divine purpose.

In contrast, others emphasize the importance of personal growth, relationships, or contributing to the well-being of others and the world. Within the framework of SWB, individuals may seek to understand and cultivate a sense of meaning in their lives through practices such as self-reflection, introspection, meditation, prayer, and engaging in meaningful activities (Bai & Lazenby, 2015). They may explore existential questions, reflect on their values, and strive to align their actions with their deepest beliefs and convictions. SWB is primarily a search for purpose and meaning beyond material pursuits, acknowledging the interconnectedness of all beings and recognizing a sense of awe and wonder in the world. It can also involve finding comfort in times of difficulty or uncertainty by believing in something greater than oneself (Damberg et al., 2020).

The last extracted factor was the sense of life. The concept of a sense of life in SWB is closely related to the meaning of life but focuses more on the subjective experience and perception of one's existence. It refers to an individual's understanding and interpretation of their life's purpose, direction, and significance (Musa, 2016). The sense of life in SWB involves finding a deep and meaningful connection to one's existence and the world around them. It goes beyond intellectual or philosophical contemplation and involves a sense of purpose, fulfillment, and coherence in one's life journey (Dehshiri et al., 2013). Developing a sense of life in SWB often requires self-reflection, introspection, and exploration of one's values, passions, and inner desires. It may involve asking oneself vital questions about their identity, values, and goals in life. Through this process, individuals can gain insight into what truly matters to them and what brings them a sense of purpose and meaning. Spiritual practices, such as meditation, mindfulness, praying, or engaging in contemplative activities, can also help individuals develop a deep sense of life. These practices can facilitate a heightened sense of self-awareness, a connection to something greater than oneself, and an appreciation for the present moment (Bai & Lazenby, 2015; Damberg et al., 2020).

In this study, after omitting the outliers, marked weak points, and checking the normal distribution of the data, the structural fit of a one-factor SWBS was investigated using CFA and a selection of relevant models. The goodness-of-fit results was appropriate for all indices, and all factor loadings were higher than 0.5, indicating the minimum acceptable factor load. Based on the results of the CFA, the observed indices were all confirmed, and all relevant parts of the indices revealed satisfactory standard levels. Only a few studies have assessed the CFA of this scale (Sharif Nia et al., 2018, 2022; Soleimani et al., 2017).

According to the final model of SWBS, there is a correlation between the measurement errors of some items (Q15–Q20 and Q2–Q6). Correlated measurement error occurs when variables have not been clearly identified or not directly measured, and such errors can affect the responses to the items. Measurement errors may result from the use of self-report data. Measurement errors can also result from similar meanings or nuances in the words and phrases of both positive and negative statements (Sharif Nia et al., 2018).

The findings of this study indicated that the items in the final model of the SWBS demonstrated convergent validity. Hair et al. stated that convergent validity is present when the items of a construct are closely related and exhibit high variance. They also believe that when divergent validity exists, the items or extracted latent factors are distinct (Hair et al., 1995). In other words, appropriate convergent validity is not achieved if the items cannot explain the latent factors and do not have a strong relationship (Fornell & Larcker, 1981).

In this study, the reliability of the SWBS was appropriately evaluated. The high value of Cronbach’s alpha indicated good internal consistency of the scale and a sufficient correlation between the items. This suggests that all the questions have similar concepts, and no conceptual dispersion. The reliability of the SWBS has been reported to be acceptable in various studies, ranging from 0.8 to 0.9 (Sharif-Nia et al., 2023). Sharif Nia et al. (2018) also calculated the reliability of this scale using Theta and McDonald Omega coefficients and found the reliability to be satisfactory. These coefficients are more applicable in psychometric studies than Cronbach's alpha (Sharif Nia et al., 2018, 2022; Soleimani et al., 2017).

There is no clear evidence to suggest that the structure of spiritual health differs significantly between men and women. Both men and women can experience spiritual health similarly, through a sense of connectedness to something greater than themselves, a sense of purpose or meaning in life, and a feeling of inner peace or contentment. However, some studies have suggested that there may be gender differences in how spirituality is expressed or experienced. For example, research has found that women are more likely than men to engage in spiritual practices such as prayer and meditation and may also be more likely to report feeling a sense of connection with others and a greater sense of empathy or compassion (Rassoulian et al., 2021; Reid-Arndt et al., 2011).

It is important to note that spirituality and spiritual health are deeply personal and subjective experiences and can vary significantly between individuals regardless of gender. It is also essential to recognize that gender is just one aspect of a person's identity and should not be used as the sole determinant of their spiritual experiences or needs. In Iran, spirituality and religion play a significant role in society, and many people view spiritual health as an integral part of overall well-being. However, it is difficult to generalize about the structure of spiritual health in Iran based solely on gender. While there may be some differences in how men and women approach spirituality, these differences are likely influenced by various factors, including cultural norms, personal beliefs, and individual experiences.

Women in Iran may be more likely to participate in religious practices and identify with a particular faith than men. In some cases, this may be due to cultural expectations that emphasize piety and modesty for women. However, it is essential to note that these trends are not absolute, and each individual's experience of spirituality will be unique to them.

Implications

This study has revealed the importance of understanding the SWB of individuals willing to donate organs. The concept of SWB can differ between healthy individuals and those facing critical situations or diseases. By gaining a deeper understanding of the population's spiritual experiences, policymakers and healthcare planners can lay the groundwork for improving people's inclination toward organ donation. Consequently, this study emphasizes the significance of incorporating spirituality into intervention programs targeting the general population to enhance their willingness to donate organs.

The implications of the SWBS scale among potential organ donors in Iran are significant in several ways. First, it can provide insights into the role of spirituality in the decision-making process regarding organ donation. Previous research has demonstrated that religious and spiritual beliefs can influence attitudes toward organ donation. Therefore, understanding the spiritual well-being of donors can aid in designing effective interventions to promote organ donation within the Iranian population.

Second, the SWBS can help identify potential barriers to organ donation. For instance, if the score on the religious well-being subscale is low among potential donors, it may indicate that religious beliefs are a significant obstacle to organ donation in this population.

Finally, the SWBS scale can also assist in identifying the need for spiritual care among potential donors and their families. Spiritual care is an integral component of end-of-life care, encompassing addressing the spiritual well-being of potential donors can help provide appropriate spiritual care during the organ donation process.

In summary, the SWBS scale offers valuable insights into the spiritual well-being of potential organ donors in Iran. This information can aid in the design of effective interventions to promote organ donation, identify potential barriers, and provide appropriate spiritual care to donors and their families.

Limitations

This study has several limitations: First, as other studies focus on specific geographical regions such as Iran, generalizability to broader populations may be limited. Therefore, caution should be exercised when interpreting these results from a broader perspective. Second, there may be information bias as the data were collected through self-report measures.

Conclusions

The findings of this study demonstrate that the Persian version of the SWBS, when applied to the Iranian population willing to donate organs, is multidimensional, consisting of three factors: higher power, the meaning of life, and sense of life. These factors account for 50.23% of the total variance in SWB among Iranians. Therefore, the Persian version of the SWBS can be considered a valid and reliable scale for assessing the SWB of potential organ donors in Iran. Future validation studies encompassing diverse communities and utilizing longitudinal designs are necessary to further refine, modify, or validate the SWBS as an additional measure of well-being.