Funding for this research was provided by:
National Institute on Aging (P01 AG041710)
Text and Data Mining valid from 2018-10-10
Received: 11 January 2018
Accepted: 5 October 2018
First Online: 10 October 2018
Compliance with ethical standards
: Ethical approval was granted by the University of the Witwatersrand Human Research Ethics Committee (M141159), the Harvard T. H. Chan School of Public Health, Office of Human Research Administration (C13-1608-02), and the Mpumalanga Provincial Research and Ethics Committee. Informed consent was obtained from all individuals included in the study. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.