1 Institute for Health & Aging, Department of Social and Behavioral Sciences, University of California, 490 Illinois St, San Francisco, CA, 94158, USA. tracy.lin@ucsf.edu.
2 Center for Population, Inequality, and Policy, University of California, Irvine, USA.
3 Saudi Health Council, Riyadh, Saudi Arabia.
4 World Bank, Washington, DC, USA.
5 Division of Health Research, Lancaster University, Lancaster, UK.
6 Institute for Health & Aging, Department of Social and Behavioral Sciences, University of California, 490 Illinois St, San Francisco, CA, 94158, USA.