1 Introduction

Elderliness as a critical period of life brings about special needs that should be considered and met as a social necessity [1]. According to epidemiological studies, 11% of the global population is over 60 years old. This number is projected to increase to 22% by 2050 [2]. The World Health Organization announced that people over 65 years will outnumber the population of children under 5 years old soon [3]. Currently however, there are significant variations among countries and continents. The elderly population in Iran is growing faster than the entire country’s population [4]. According to the 2016 national census, about 9.3% of the Iranian population were at the age of 60 years and older [5]. This proportion is expected to grow rapidly and exceed 11% by 2030 [6]. Therefore, paying attention to the various needs of the elderly is essential.

One of the critical issues in the elderly is the sense of coherence (SOC) [7]. The SOC as presented by Antonovsky reflects a person’s perception and is a life orientation [8]. SOC developed in the 1970’s focuses on the factors supporting human health and well-being and refers to using internal and external resources for coping with stressors and maintaining health. This concept aims to explain how people stay healthy rather than getting sick. In this regard, Antonovsky defined three components: comprehensibility, manageability, and meaningfulness. Comprehensibility is the degree of meaningfulness of events, while manageability refers to the degree to which a person feels to be able to cope with events, and meaningfulness means the degree to which a person feels that life is meaningful [9]. The way people perceive life and use their resources to cope with stressors is reflected in SOC and thus it can be considered a health resource [10] and a critical health factor influencing coping [11]. In addition, Erikson and Lindström have shown that SOC is essential in maintaining physical and mental health, development, and quality of life (QOL) [12]. A strong SOC has been shown to protect against adverse health outcomes in terms of depression, according to studies [13], poor QOL [14], disability [15], and mortality [16].

Functional status, mental health, and personal well-being are related to SOC in the elderly, so a higher SOC is associated with greater psychological well-being and is an essential factor in predicting the QOL of the elderly [1]. Parker considers the SOC as a source of peace and security that will be associated with the psychological well-being of the elderly [7]. According to Erikson, a higher SOC in the elderly is associated with positive attitude, physical performance, and social support leading to improved QOL and decreased anxiety [4].

Studying QOL is essential to understand the consequences of illness and treatment, and for medical decision-making in various age groups and cultures [17]. By using QOL, we can assess the mental health of societies and how much diseases, injuries, and disabilities impact them [18]. A person's QOL is how they see themselves in their culture and values, and how that relates to what they want, expect, judge, and prioritize in life, according to the World Health Organization [10].

Though many studies have centered on the QOL and the SOC [19,20,21], it appears that the relationship between the SOC and its role as a protective factor in improving the QOL has not been thoroughly elucidated among elderly individuals in Iran. In light of the global aging phenomenon and the increasing mortality rates, particularly from age-related diseases [22, 23], this study seeks to examine how SOC influences the QOL in the elderly population.

The cross-sectional design for conducting the current study has been employed for several reasons. Firstly, it allows for a more representative sample of the population as compared to the qualitative protocol due to the larger sample size. Secondly, it promotes objectivity in data collection and analysis through the use of questionnaires, thereby reducing bias. Additionally, this approach enables us to compare similar groups, aiding in the understanding of patterns, differences, and the needs of the populations. So, The study was conducted in Qom, Iran from June to October 2022 explored the relationship between SOC and QOL in elderly Iranians.

2 Methods

2.1 Setting and design

This study was done in Qom, a central Iranian city that is holy, using a cross-sectional method from June to October 2022.

2.2 Participants

The research focused on older adults who were members of retirement centers in Qom, Iran. A sample size of 248 was determined based on a previous study, utilizing a sample size formula with a Confidence coefficient of 99% and a statistical power of 90%. Ultimately, 300 older adults living in a retirement center were chosen through convenience sampling.

In order to participate, individuals had to be 60 years or older, free from any history of psychiatric disorders or psychoactive drug use, and residents of the Qom region for at least six months to ensure familiarity with the environment and daily routines. Additionally, effective communication skills were necessary, and participants had to willingly volunteer for the study.

2.3 Measures

The study questionnaires were completed by the patients, or by the researchers if the patients were unable, as follows:

  1. 1.

    A questionnaire for clinical and socio-demographic information, including questions about gender, age, educational status, marital status, employment, and economic status perception, body mass index (BMI), use of aimed devices (such as canes, walkers), and comorbidity.

  2. 2.

    LEIPAD as an internationally applicable instrument was used to assess QOL in the elderly. LEIPAD is a 31 item self-assessment questionnaire with 7 subscales including: physical function, self-care, depression and anxiety, cognitive functioning, social functioning, sexual functioning, and life satisfaction. Each attribute is rated on a 4-point Likert scale. The total score ranges from 0–93, lower scores representing better QOL and higher scores representing worse or poorer conditions. The reliability and validity of both the original and Persian versions of LEIPAD were found to be good in previous evaluations [24, 25].

  3. 3.

    The Iranian version of the SOC-13 questionnaire to assess the SOC among the elderly. It was developed by Antonovsky (1987) and consists of 13 items that measure how people perceive their lives as comprehensible, manageable, and meaningful. For comprehensibility, an example item asks if the individual feels they are in an unfamiliar situation and don't know what to do. For manageability, an example item asks if the individual has experienced disappointment from people they relied on. Lastly, for meaningfulness, an example item asks if the individual's life has had clear goals or purpose. Each attribute is rated on a 7-point Likert scale from 1 to 7. The score ranges between 13 and 91 points and higher total scores indicate a stronger SOC. Internal consistency assessed using Cronbach alphas, and the results showed a score of 0.77. Alpha values for the SOC were 0.74, 0.78 and 0.77; for meaningfulness were 0.54, 0.58, and 0.56; for manageability were 0.45, 0.50, and 0.48; for comprehensibility were 0.52, 0.63, and 0.61 [8, 26].

2.3.1 Statistical analysis

The study used SPSS version 24 for statistical analyses and applied descriptive statistics, an independent t-test, and one-way analysis of variance for comparison purposes. Also, multiple linear regression analysis was applied in the study to investigate the association between SOC and QOL while controlling for socio-demographic and clinical variables.

Ethical considerations: with registration number IR.MUQ.REC.1400.247, the study was approved by the Ethics Committee of the Qom University of Medical Sciences. Prior to their participation, the participants were given an explanation of the study's purpose. They entered the study with informed consent and they were assured that their responses and information would be kept confidential and then, questionnaires were completed through interviews with participants. To maintain the confidentiality of the information, the data were analyzed anonymously and all relevant guidelines were followed to assure the ethical considerations of the study.

3 Result

In all, 325 people meeting the inclusion criteria of the study were approached, out of whom, 300 individuals agreed to participate in the study (response rate 92.3%). The majority of participants were male (77.3%) and married (88.7%), and they had a mean age of 64.4 (SD = 5.72) years. Fifty-one percent of them lived with their families. The detailed demographic characteristics of the participants are shown in Table 1.

Table 1 Socio–demographic information of the study sample (n = 300)
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Table 2 shows the mean score for QOL variables and SOC. Sexual functioning had the lowest score (5.09 ± 1.97), while self-care had the highest score (7.37 ± 2.58). The mean score for comprehensibility, manageability, and meaningfulness were 21.40 ± 5.27 and 16.73 ± 4.68, and 20.26 ± 4.48 respectively.

Table 2 Descriptive statistics for quality of life and sense of coherence
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Multiple linear regression analysis was used to examine the association between QOL and SOC. The dependent variables were the subscales of QOL, and the independent variables were the SOC and the socio-demographic factors. After adjusting for socio-demographic and clinical factors, the multiple linear regression model revealed that comprehensibility was linked to better physical functioning (β =− 0.64; P = 0.036), and manageability was linked to better cognitive functioning (β = − 0.157; P = 0.016), social functioning (β = − 0.27; P = 0.001), and life satisfaction (β = − 0.215; P = 0.003). There was an association between meaningfulness and QOL subscales except for self-care and life satisfaction. The results for each of the seven subscales are shown in Table 3.

Table 3 Results of multiple linear regression analysis for quality of life
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4 Discussion

The study examined the relationship between SOC and QOL in the elderly population. A significant relationship was observed in the present study between the overall score of QOL and all its dimensions. Previous research has shown that a strong SOCacts as a protective factor for health-related QOL. Fok (2005) discovered a significant correlation between a strong SOC and improved QOL and coping abilities among critically ill patients. Additionally, In line with our study, Jia Yi Tan et al. [19] investigated the impact of SOC, resilience, and loneliness on QOL among the elderly in long-term care centers. They discovered that manageability and meaningfulness, as subscales of SOC, exhibited a significant positive association with QOL. Asgari et al. [4] studied the QOL of the elderly based on internal coherence, mindfulness, and spiritual intelligence and found a positive and significant relationship between internal coherence and QOL. In addition, the study by Joanna Dymecka et al. [27] explored the relationship between SOC and QOL in patients with multiple sclerosis, finding a significant relationship between them. This systematic review has found further support indicating that a stronger SOC is linked to enhanced physical and psychological well-being, as well as increased involvement in preventive and self-management activities among older adults living in the community [28]. In contrast to the present study, the study of Vera Gerasimčik-Pulko et al. [29] found no significant relationship between QOL and SOC in patients with the early stages of breast cancer.

In the population under study, the meaningfulness subscale had the highest average SOC score according to the study's findings, while the manageability subscale had the lowest. This is partly different from the findings of Fayazi et al. [1] that revealed the highest average for comprehension subscale and the lowest average for manageability subscale in a sample of Iranian elderly with cancer. In another study, Ruo-Nan Jueng et al. [30], investigated the SOC among the elderly living in long-term care centers in Taiwan and found that the score of comprehensibility was the highest and the score of meaningfulness was the lowest. Differences in subjective experiences or cultural backgrounds may impact an individual's intrinsic beliefs, which could explain the variation in SOC across studies. For instance, in previous studies, it has been observed that the older population tends to exhibit stronger religious affiliations in their behavior, and the significance of religion becomes more pronounced during pivotal moments in an individual's life, such as old age. [31]. The present study was carried out in one of the cities recognized as the religious hub in Iran, and earlier research has underscored the influence of beliefs on the lives of its inhabitants [32], which could account for the relatively positive scores in terms of SOC.

Based on the current research findings, the average QOL in the elderly was evaluated at a moderate level. In line with the present study, Marufkhani et al. [33] studied the QOL in the Iranian elderly, Yousefi Afrashteh et al. [34] investigated the association of spiritual health and social support with QOL in the rural elderly and Amirzadeh-Iranagh et al. [35] examined predictive components of QOL among retired older adults in Urmia. Other studies have reported that older adults have lower QOL levels [36,37,38]. To explain the diverse findings, the average age, physical condition, and place of residence of the elderly under study may be regarded as factors affecting the QOL levels. Previous studies have suggested that as people get older, the QOL tends to decrease [39], However, the findings of the present study are somewhat at odds with these results. The current study emphasizes the possibility that, despite the general trend, factors affecting the QOL for elderly individuals could potentially improve. This study showed the scores of self-care as a subscale of QOL the highest compared to the other subscales and the sexual performance had the lowest scores. These are in agreement with the findings of Maghsoudi et al. [40], who reported the best condition for the self-care and in contrast to the findings of Hasani et al.'s study [41], who reported the best situation for the subscale of sexual performance among the elderly with peripheral neuropathy in 2019. Given that advancing years are often linked with physiological limitations [42], it came as no surprise that there were low scores in relation to sexual performance.

There are limitations in our study that must be acknowledged. Our study design was cross-sectional, which hinders our ability to definitively establish causality. Longitudinal studies would offer more substantial evidence regarding the temporal relationship between SOC and QOL. It is important to note that our study sample consisted solely of Iranian older adults, which may not fully represent the diverse older populations found in other regions or cultural contexts. Therefore, caution should be exercised when attempting to generalize our findings to other ethnic or socio-economic groups. Additionally, both SOC and QOL were evaluated using self-report questionnaires, which may be susceptible to recall bias, social desirability, or subjective interpretation. We did not thoroughly investigate the impact of specific health conditions or comorbidities on SOC and QOL. Future research should delve deeper into how chronic illnesses influence these constructs. Finally, while we did identify an association between SOC and QOL, we did not extensively explore the influence of religious beliefs, cultural norms, and social support systems. These factors could significantly contribute to an individual's SOC and overall well-being. Therefore, it is recommended that future research studies concentrate on examining the impact of these factors.

5 Conclusion

This study demonstrates the importance of the SOC for the QOL among the elderly as a conclusion. To improve the QOL among older adults, it is recommended to implement interventions and provide consultations aimed at fostering a heightened SOC.

Understanding the role of SOC in older adults’ QOL opens avenues for targeted interventions, research, and policy development. By addressing both SOC and specific QOL dimensions, we can enhance well-being and resilience in this population.