Article History
Received: 20 October 2021
Accepted: 17 December 2021
First Online: 15 January 2022
Declarations
:
: On behalf of all authors, the corresponding author states that there is no conflict of interest.
: All methods were carried out in accordance with relevant guidelines and regulations at the time of the field examinations, performed in early 1960s. In particular, since baseline data were collected before the era of the Helsinki Declaration (June 1964), with consent implied by participation in the examinations, there were no expressed approvals from institutional or licensing Committees.
: There were subsequently verbal or written consents given by all informed participants to collect follow-up data.