1. Introduction
oneliness is one of the psychosocial problems and unpleasant experiences that have received less attention, associated with quantitative or qualitative social relationships deficiencies [1, 2]. Loneliness is an undesirable result of the disruption of essential connections. The person experiences significant social communication limitations and failure to meet the needs related to intimate communication, and the quality of relationships is not enriching for the individual [3, 4]. The phenomenon of loneliness is experienced in all age groups, but the determinants of loneliness are more pronounced in the elderly. This age group is more involved with loneliness due to experiencing losses such as a spouse's death, decreased physical function, and health problems [5]. 
Due to the lack of a suitable questionnaire to assess loneliness in the Iranian elderly community, there is little information about the extent of this problem in the Iranian elderly population. On the other hand, Gierveld Loneliness Questionnaire has been translated and implemented in many cultures and languages. The preparation of a native version and validation of this questionnaire in Iran can determine the extent of this problem in the Iranian elderly and allow the cross-cultural comparison of loneliness among the Iranian elderly with the elderly of other countries. Therefore, this study was conducted to translate and psychometric evaluation of the 6-item version of the Gierveld Loneliness Questionnaire.
2. Methods & Materials
The present methodological research was taken from a research project at Lorestan University of Medical Sciences entitled Translation and Psychometrics of the 11-item version of the Girold loneliness Questionnaire, approved by the University Ethics Committee (Code: LUMS.REC.1396.259).
Research community
Participants in this study were elderly people over 60 years old living in Khorramabad City. The sample size in psychometric studies is determined based on the number of items. However, to ensure a sufficient sample size in the study, 224 people (30 people per question) were selected. Also, to evaluate the questionnaire's reliability, the sample size was considered for evaluation by the retest method of 30 people.
Tools
The questionnaires used in the study included demographic factors questionnaire, cognitive shortened test questionnaire, hospital depression anxiety questionnaire, and 6-item version of Girold loneliness questionnaire. The Hospital Anxiety and Depression Questionnaire is a 14-item tool for assessing anxiety and depression in patients that have been designed with an emphasis on the effect of physical illness on the total score [20]. Depressive questions in this tool focus more on the symptoms of lack of anhedonia. This tool gives the researcher a score for depression and a score for anxiety and differentiates between the two disorders. A score greater than 11 in each of the two dimensions of the questionnaire indicates anxiety or depression [20].
Version 6 of the questionnaire was developed by De Jong and Van Tilburg in 2006 [21]. The questionnaire consists of 6 questions with 3-point Likert answers including no, more or less, and yes. 3 of the questions have a negative charge, and 3 cases have a positive account. Questions 1, 5, and 6 have positive and neutral answers related to emotional loneliness, and questions 2, 3, and 4 have negative and neutral answers and are related to social loneliness [14]. This questionnaire has two dimensions of emotional and social loneliness [14]. Theoretically, this tool measures mild and severe feelings of loneliness and feelings of hidden deprivation [17]. The questionnaire's total score includes the sum of 2 scores of the subscale, and the loneliness score is valid only if all the questions have been answered or at most one question remains unanswered [21].
3. Results
The study Results showed out of 224 elderly participants in the study, 53.1% (119) were male. The minimum age of the elderly samples was, 60 and the maximum was 105 years. The Mean±SD age of the participants was 67.5±7.6. 53.1% of the samples were male, 70.5% were married, and 55% were illiterate. 66% lived with their spouse and 4.9% alone. Also, 26% of the elderly participants in the study were retired. The minimum number of children of the elderly participating in the study was 1, and the maximum was 13, and the average number of children was 2.26±6.55.
Content validity
The content validity Results of the questionnaire (CVI coefficient) showed the questionnaire has an acceptable content validity index (CVI=0.874) (0.833 on the correlation scale, 0.854 on the resolution scale, and 0.937 on the simplicity scale).
Criterion validity
The criterion validity Results using the Pearson correlation test showed there is a positive and significant relationship between the social dimension of the loneliness tool with anxiety, depression, and the total score of depressive anxiety (P<0.001).
Structural validity
Confirmatory factor analysis was used to evaluate the construct validity of the loneliness 6-item tool. According to the model fit indices (RMSEA=0.047, IFI=0.983, GFI= 0.983, CMIN / DF=1.48) and the factor load associated with each question, It turned out the 6-question tool has an acceptable fit with the two factors of emotional and social loneliness. Also, there was a positive and significant correlation between emotional and social loneliness (P<0.001, r =0.50).
Reliability
The questionnaire reliability evaluation Results through intra-class correlation coefficient also indicated the instrument's appropriate reliability (P=0.002, ICC=0.743). Also, the internal consistency study Results showed the instrument has good internal consistency (α=0.698)
4. Conclusion
This study aimed to translate and psychrometer the 6-item Dejang Loneliness Questionnaire. This tool is one of the most common loneliness measurement tools, especially in the elderly population, and has been translated and localized in various languages. This study investigated different psychometric properties of the mentioned tools including, face validity, content validity, concurrent validity, structural validity, and internal consistency and reliability, as the demographic Results show. Participants in the study consisted of all age groups of the elderly and were almost equal in terms of sex ratio. In this case, we seem to have reached more realistic Results from the evaluations made. Waltz and Bausell's content validity index was used to determine content validity. The content validity Results of the questionnaire showed the value of the content validity index for the whole questionnaire and its dual dimensions is higher than the amount suggested by Hyrkas et al. (Score 0.79 and above) [23] Therefore, the Persian version of the Dejang Girold 6-item questionnaire has good content validity.
The convergent validity study Results using the Hospital Depression Anxiety Questionnaire showed a positive and significant relationship between emotional and social loneliness and total loneliness with anxiety, depression, and total depression anxiety scores. Many studies have suggested a strong association between loneliness and depression [25, 26]. These Results show loneliness is associated with depression and anxiety, and the questionnaire has good convergent validity. This result is consistent with the Buz and Archadra Results and other studies that have used concurrent validity to assess the Gerold Loneliness Questionnaire's psychometrics [16, 17]. Buz and Archadra have reported a positive and significant relationship between loneliness and depression and a negative relationship between loneliness and life satisfaction [17].
Ethical Considerations
Compliance with ethical guidelines
This study was approved by the Ethics Committee of the University of Lorestan University of Medical Sciences.
Funding
This research was supported by the University of Lorestan University of Medical Sciences. 
Authors' contributions
All authors equally contributed to preparing this article.
Conflicts of interest
The authors declared no conflict of interest.
 

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