Introduction
The elderly are exposed to potential threats such as increased incidence of chronic diseases, loneliness, isolation, and lack of social support [5]; these threats cause the elderly to be dependent on caregivers, which affects the elderly physically and cognitively and brings challenges for caregivers [18]. The aggressive behavior of the elderly towards the caregivers is an important challenge and problem in the nursing homes. The issue of caregiver abuse of the elderly has been neglected in national studies. Field reports indicate that caregiver abuse is a growing phenomenon that can lead to physical problems, emotional stress, quitting job, or job burnout in caregivers [19]. This study aims to investigate the prevalence of caregiver abuse in nursing homes of Tehran, Iran and its related factors.
Methods
This is a cross-sectional study that was conducted in 2018. The study population consists of official caregivers of the elderly in nursing homes in Tehran. Using a convenience sampling method, samples were selected from 14 existing nursing homes. By considering P=0.05 and test power of 90%, the sample size was determined 110. By considering 20% dropout, it was reached to 124.
The data collection was the Survey of Violence Experienced by Staff (SOVES) questionnaire developed by McKenna in 2004. This tool measures three types of verbal abuse, physical abuse, and threats. The content validity of the Persian version of SOVES was determined based on the opinions of seven experts, and α=0.99 was obtained for its reliability. Data were analyzed in SPSS v. 24 software.
Results
The mean age of caregivers was 36.74±8.38 years. Among 124 participants, 68.5% were female. The prevalence of the caregiver abuse of the elderly in the last 12 months was 42.7%. Of this, 37.1% was related to verbal abuse, 24.2% was physical abuse, and 12.9% was threats. In order to investigate the factors related to caregiver abuse, chi-square, independent t-test and Mann-Whitney U test were used. The results of chi-square test showed that the employment status of caregivers had a significant relationship with the experience of abuse; full-time caregivers were 4 times more likely to be abused (X2=7.43, P<0.05, OR=4.032). The variables of gender (X2=0.271, P>0.05), history of self-defense training (X2= 0.38, P>0.05) and receiving training in the management of potentially aggressive people (X2= 0.62, P>0.05) had no significant relationship with caregiver abuse. The results of independent t-test results showed that age (t=1.66, P>0.05) and percentage of direct contact with the elderly (t=4.23, P>0.05) had no relationship with caregiver abuse. The results of the Mann-Whitney U test showed no statistical relationship between work experience and caregiver abuse (U=7.43, P>0.05).
Discussion
A significant percentage of caregivers in nursing homes of Tehran are at risk of abuse by the elderly. All caregivers, regardless of age, gender, work experience, employment status, direct contact, and history of receiving training, are exposed to abuse by the elderly. The attention should be paid to this vulnerable group by policy makers and professionals by planning and implementing appropriate interventions and programs to protect them, especially for the full-time caregivers.

Ethical Considerations
Compliance with ethical guidelines
Informed consent was obtained from all participants. This study was approved by the ethics committee of University of Social Welfare and Rehabilitation Sciences (Code: IR.USWR.REC.1398.155).

Funding
This plan was funded by the Aging Research Committee of the University of Rehabilitation Sciences and Social Health. Also, this article is taken from a research project titled "The extent and factors related to caregiver abuse in nursing homes in Tehran".

Authors' contributions
All authors contributed equally in preparing all parts of the research.

Conflicts of interest
The authors declared no conflict of interest.

Acknowledgements
The authors are grateful for the cooperation of the Country's Welfare Organization and the managers of the nursing homes in Tehran.


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