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Article History

Received: 1 December 2017

Accepted: 17 May 2018

First Online: 18 July 2018

Ethics approval and consent to participate

: As it is stated earlier, no formal institutional approval for the investigation protocol could be obtained due to absence of medical ethics committee in the early 1970’s. However, the both the baseline (retrospectively) and the follow-up study and further usage of data for medical research and scientific publication was approved by the regional committee for medical and health research ethics ((REK nr. 188/89).

: The authors declare that they have no competing interests.

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