Institute of Tropical Medicine and International Health Berlin, Charité - Universitaetsmedizin Berlin, Berlin, Germany. Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal, Germany. Heidelberg Institute of Global Health, University of Heidelberg, Heidelberg, Germany; Department of Global Health and Population, Harvard T.H. Chan School of Public Health, Boston, USA; Africa Health Research Institute (AHRI), Somkhele and Durban, South Africa. Department of Molecular Epidemiology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), Nuthetal, Germany; Institute for Social Medicine, Epidemiology and Health Economics, Charité - Universitaetsmedizin Berlin, Berlin, Germany. Electronic address: ina.danquah@dife.de.