Materials and Methods

The current study is a case study and part of the first phase of the elderly cohort plan, approved by the Ethics Committee of Babol University of Medical Sciences (IR. MUBABOL. HRI. REC. 1397.054) and performed on all people 60 years older and above living in Amirkola City in 2019. Of the 1,616 elderly people surveyed in the first phase, 59 had a disability in daily living activities (ie, the prevalence of disability was estimated at 3%), which was considered as the case group, and more than three times (212 people) were considered as the control group. Inclusion criteria for the Amirkola cohort study were people’s consent to participate. Exclusion criteria were incomplete completion of questionnaires and unwillingness to continue the investigation.