Funding for this research was provided by:
Health Research Council of New Zealand (17/007)
Received: 22 March 2020
Accepted: 28 December 2020
First Online: 18 January 2021
Ethics approval and consent to participate
: Ethics approval was given by the University of Otago in February 2017 (F17/002) and the Tonga Government awarded a Research Permit for the study on 29 June 2018 (Org 1/8 V.18). Permission to use the datasets was granted by the Government Statistician in Tonga. Anonymised data was provided for data analysis by Pacific Community.
: Not applicable.
: The authors declare that they have not competing interests.