Tehran University of Medical Sciences Journal of Biostatistics and Epidemiology 2383-4196 9 3 2023 09 15 336 350 ahmad delbari Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Elahe Hesari Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Mohammad Saatchi Department of Biostatistics and Epidemiology, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Mohammad Bidkhori Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Seyedeh Saleheh Mortazavi Geriatric Mental Health Research Center, School of Behavioral Sciences and Mental Health (Tehran Institute of Psychiatry), Iran University of Medical Sciences, Tehran, Iran. Elham Hooshmand Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. 2023 08 23 2024 02 06 Introduction: Elderly people usually feel lonely that can have adverse health effects. The purpose of current paper is to determine the loneliness score in the elderly population of the Ardakan Cohort and the factors affecting it. Methods: This is a cross sectional study using data from the Ardakan Cohort Study on Ageing (ACSA). Loneliness was measured using a 6-item De Jong Gierveld short scales. The 11-item Duke Social Support Index (DSSI) was used to measures social support of aging. living arrangement, demographic factors and self-rated health was also collected using a checklist. Linear regression was used to examine the relationship between loneliness and predictor factors. The data was analyzed with Stata software version 17 and a p-value of 0.05 was considered as a significant level. Results: Among the 5,188 participants, 48.13% were male and most of the participants were over 60 years old. Total score of loneliness was 3.27±1.45(95% CI: 3.24 to 3.31). Among covariates, age (p value=0.000), sex (p value=0.000), marital status (p value=0.046), education (p value=0.001) and economic status (p value=0.001) have significant association with loneliness score. People with good self-rated health had a lower loneliness score (p value<0.001). The score of social support has an inverse association with the score of loneliness (p value<0.001). Adults who lived with others had a higher loneliness score (p value<0.001). Conclusion: According to the results, elderly people who have more social support and have better self-rated health feel less lonely.   https://jbe.tums.ac.ir/index.php/jbe/article/view/1279 https://jbe.tums.ac.ir/index.php/jbe/article/download/1279/452