Introduction
Significant differences exist in the living arrangements of older adults in different countries under the influence of social and cultural norms as well as economic conditions. In developed countries, about three-quarters of older adults, and in developing countries, only one-quarter, and in less developed countries, one-eighth of older adults live independently. However, in developing countries, including Iran, the living arrangements of older adults are more crucial because the role of the family in supporting older adults is much greater, and also the governments cannot provide all the supports needed by older adults due to the lack of developed health and care systems. 
In the future, with the development of developing countries and the aging of their population, living alone or only with a spouse will become very common among older adults. Therefore, according to the increase in life expectancy and the change in the family structure from extended to nuclear, changing the pattern of living arrangements of older adults has become a socio-political issue. In this regard, this article aims to investigate the patterns of living arrangements of older adults and the relationship between various demographic and social factors with them.
Methods 
In this study, the secondary analysis of the two percent data of the censuses of 2006 and 2016 was used. The studied population includes people older than 60 years living in normal households. The number of older adults surveyed in 2006 was 106 057 people and in 2015, it was 147 602. The dependent variable in this research is the living arrangements of older adults, which was made based on two questions related to the head of the household and the dimension of the household, and it was operationalized in the five classes of pattern, alone, only with a spouse, only with children, with a spouse and children, and other relatives. Independent variables include age, gender, education level, employment status, housing ownership, and place of residence. Multivariate logistic regression tests and SPSS version 25 software were used for data analysis.
Results 
The results of the study showed that living with a spouse and children is the dominant form of living arrangement for older adults in Iran. However, the share of this pattern was almost constant in the decade of 2006-2016, and on the other hand, the share of older adults who lived alone has increased from 12% to 15%. A significant gender difference was observed in living alone, and its ratio for elderly women (24.1%) was four times higher than for elderly men (5.6%). Also, the results of the multivariate analysis in Table 1 showed that the probability of living alone among older adults is lower in early old age and increases with age.


Compared to the pattern of living alone, the probability of cohabitation with a spouse and cohabitation with a spouse and children among uneducated and low-educated older adults is less than among university-educated older adults. In other words, the results showed that with increasing age, the probability of living alone increases, and with increasing education level, the probability of living alone among older adults decreases. In addition, rural older adults are more likely to live alone than urban older adults.
In addition, the results showed that compared to living alone, the probability of cohabitation with a spouse and children for older adults with income without work is lower than the employed. Living alone is more common among older adults who lack housing, and this situation can be a double pressure on older adults who live alone. Finally, the results showed that the probability of living alone and living only with a spouse among rural older adults is significantly higher than the urban older adults.
Discussion
Old age is usually associated with many changes, such as changes in family structure and living arrangements, changes in work pattern and transition to retirement, changes in health status, and identity changes. Some older adults can adapt to these changes and create a good old age for themselves; however, some older adults cannot, and as a result, problems arise in their physical, mental and social health. The results of this study showed that although living with a spouse and children is still the dominant pattern, living alone among older adults is increasing. Women are more likely to live alone than older men and face more problems. Therefore, paying attention to the issues and problems of the alone elderly women should be the headline of the country’s welfare programs and policies. In addition, by creating employment in rural areas, it is possible to prevent the migration of young people to the city to some extent and reduce the possibility of living alone among rural older adults.

Ethical Considerations
Compliance with ethical guidelines
This study was registered with the code of ethics IR.UT.REC.1398.054 at the University of Tehran. 

Funding
This article is the result of the MA thesis of Mrs. Fatemeh Sadat Khodaparast in the Faculty of Social Sciences, University of Tehran. 

Authors' contributions
Both authors contributed equally to preparing all parts of the article.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
We thank the reviewers for all their valuable comments and suggestions, which helped us to improve the quality of the manuscript.

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