Selected publications by members of the chair. Click a name to expand the list.
Full publication list →
Bogler L, Ochmann S, Owolabi KE, Weber A-C, Okunlola JO, Vollmer S (2026) Primary school characteristics in Sokoto State, Nigeria . Scientific Data , 13: 539
Mittal N, Vollmer S (2026) Savings behaviour and livelihoods before and after COVID-19 – a four round panel dataset from Pune, India . Scientific Data , 13: 318
Bogler L, Weber A-C, Kumar A, Vollmer S (2026) Iron-Fortified Drinking Water in Anganwadi Centres in Rural India: A Randomized Controlled Trial . Review of Development Economics
Albanna B, Hesch G, Naeher D, Otto D, Jain M, Mehedy Hassan M, Vollmer S, Ewell H, Nawrotzki R (2026) Assessing the adoption and outcomes of early-sown wheat varieties in Northwest India . International Journal of Agricultural Sustainability , 24(1): 2603756
Bogler L, Kumar A, Subramanian SV, Vollmer S (2025) Effects of a large-scale participatory learning and action programme in women’s groups on knowledge and behaviour related to pregnancy and childcare: a cluster-randomized controlled trial in Bihar, India . SSM - Population Health , 32: 101880
Ebert C, Klasen S, Vollmer S (2025) Counting missing women: a reconciliation of flow and stock measures . Journal of Population Economics , 38(4): 82
Ahmad A, Naeher D, Vollmer S (2026) The Political Economy of Patent Buyouts . RAND Journal of Economics , 57(2): 315-333
Naeher D, Vollmer S (accepted) General vs. Tailored Information for Technology Adoption: Evidence from a Cluster Randomized Controlled Trial in India. Journal of Development Economics (Registered Report Stage 1: Proposal )
Bogler L, Vieira B, Andriamasy HE, Rapanjato Z, Vollmer S, Bärnighausen T, Ralisimalala A, Emmrich JV, Knauss S (2025) The Impact of a Mobile Money–Based Intervention on Maternal and Neonatal Health Outcomes in Madagascar: Cluster-Randomized Controlled Trial . JMIR Public Health and Surveillance , 11: e70182
Parigi M, Mittal N, Vollmer S (2025) Social cohesion among Syrian and Turkish children, adolescents, and young adults in Turkey: Data from Turkey . Scientific Data , 12: 1417 [Data ]
Teufel F, Roddewig P, Marcus M, Theilmann M, Andall-Brereton G, Aryal K, Azadnajafabad S, Bovet P, Dorobantu M, Farzadfar F, Houehanou C, Sibai A, Stokes A, Labadarios D, Gurung M, Jorgensen J, Karki K, Lunet N, Saeedi Moghaddam S, Mwangi KJ, Sturua L, Flood D, Bärnighausen T, Geldsetzer P, Damasceno A, Davies J, Vollmer S, Ali MK, Manne-Goehler J, Bulstra C (2025) National Evidence on Glucose-Lowering Medication Use for Diabetes from 62 Low- and Middle-Income Countries . Nature Communications , 16: 7139
Bogler L, Kumar A, Subramanian SV, Vollmer S (2025) Effects of a participatory learning and action programme in women’s groups on adolescent girls: a cluster-randomized controlled trial in Bihar, India . SSM - Population Health , 31: 101840
Sommer M-L, Bogler L, Subramanian SV, Vollmer S (2025) The impact of a participatory learning and action intervention on unmet need for contraception: a cluster-randomized controlled trial in rural Bihar, India . Reproductive Health , 22: 121
Stehl J, Vonderschmidt A, Vollmer S, Alexander P, Jaacks L (2025) Gap between national food production and food-based dietary guidance highlights lack of national self-sufficiency . Nature Food , 6: 571–576
Ghalichi L, Damasceno A, Flood D, Geldsetzer P, Gurung M, Marcus M, Mwangi KJ, Vollmer S, Theilmann M, Davies J (2025) Unintentional injuries requiring medical attention in low-income and middle-income countries: Evidence from nationally representative surveys in 12 countries . Journal of Epidemiology and Global Health , 15: 82
Reuter A, Marcus M, Rogge L, Diba F, Marthoenis M, Vollmer S (2025) Hypertension and diabetes screening uptake in adults aged 40–70 in Indonesia: a knowledge, attitudes, and practices study . BMC Global and Public Health , 3: 44
Stehl J, Depenbusch L, Vollmer S (2025) Global poverty and the cost of a healthy diet . Food Policy , 132: 102849
Ezebuihe J, Ochmann S, Vollmer S (2025) Gender Stereotypes and Academic Performance: Insights from Primary School Pupils in Sokoto State, Nigeria . Education 3-13 , DOI: 10.1080/03004279.2025.2467913
Rhode S, Rogge L, Marthoenis M, Seuring T, Zufry H, Bärnighausen T, Sofyan H, Manne-Goehler J, Vollmer S (2025) Real-world smartphone-based point-of- care diagnostics in primary health care to monitor HbA1c levels in people with diabetes . Communications Medicine , 5: 37
Vollmer S, Laillou A, Albers N, Nanama S (2025) Measuring child food poverty: understanding the gap to achieving minimum dietary diversity . Public Health Nutrition , 28: e27
Mittal N, Parigi M, Vollmer S (2025) Social cohesion among Syrian and Turkish children, adolescents, and young adults in Turkey . International Migration , 63: e13346
Frohnweiler S, Heesemann E, Perez-Alvarez M, Santos Silva M, Vollmer S (2025) Hospital construction and emergency waiting time: Evidence from Nicaragua . Journal of Development Effectiveness , 17(2): 161–177
Eisenburger E, Jauregui Ulloa E, Villegas Balderrama CV, Villegas Balderrama KJ, Munoz-Rodriguez SN, Calderon Escalante A, López Alonso SJ, Orona Escápite A, Flores Olivares LA, Muñoz De la Riva M, Kunde T, Tolo A, Vollmer S (2024) Addressing Physical Inactivity in Mexican Children: The Role of Parents and Their Physical Literacy . Obesity Science and Practice , 10(6): e70028
Marcus M, Reuter A, Rogge L, Vollmer S (2024) The Effect of SMS Reminders on Health Screening Uptake: A Randomized Experiment in Indonesia . Journal of Economic Behavior and Organization , 227: 106715
Weber A-C, Bogler L, Vollmer S (2024) Formal vs. informal mathematics: Assessing numeracy with school and market items in a large sample of school-aged children in North-West Nigeria . Economics of Education Review , 102: 102564
Merkel L, Teufel F, Carvalho Malta D, Theilmann M, Marcus M, Flood D, Geldsetzer P, Manne-Goehler J*, Petrak F*, Vollmer S*, Davies J* (2024) The association between depressive symptoms, access to diabetes care, and glycemic control in 5 Middle-income countries . Diabetes Care , 47(8): 1449–1456 (*joint last authors)
De Neve J-W, Karlsson O, Rai RK, Kumar S, Vollmer S (2024) Relationship between adolescent anemia and school attendance observed during a nationally representative survey in India . Communications Medicine , 4: 112
Geldsetzer P, Tisdale R, Stehr L, Michalik F, Lemp J, Aryal K, Damasceno A, Houehanou C, Jorgensen J, Lunet N, Mayige M, Moghaddam S, Mwangi K, Bommer C, Marcus M, Theilmann M, Ebert C, Atun R, Davies J, Flood D, Manne-Goehler J, Seiglie J, Bärnighausen T, Vollmer S (2024) The prevalence of cardiovascular disease risk factors among adults living in extreme poverty . Nature Human Behaviour , 8: 903–916
Bogler L, Bommer C, Ebert C, Kumar A, Subramanian SV, Subramanyam M, Vollmer S (2024) Effects of a large-scale Participatory Learning and Action Programme in Women’s Groups on Health, Nutrition, Water, Sanitation, and Hygiene: a Cluster-Randomized Controlled Trial in Bihar, India . Journal of Development Effectiveness , 16(2): 246–263
Yoo SG, Chung G, Bahendeka S, Sibai A, Damasceno A, Farzadfar F, Rohloff P, Houehanou C, Norov B, Karki K, Azangou-Khyavy M, Marcus M, Aryal K, Brant L, Theilmann M, Cífková R, Lunet N, Gurung M, Mwangi JK, Martins J, Haghshenas R, Sturua L, Vollmer S, Bärnighausen T, Atun R, Sussman J, Singh K, Moghaddam SS, Guwatudde D, Geldsetzer P, Manne-Goehler J, Huffman M, Davies J, Flood D (2024) Global Prevalence of Aspirin Use for Primary Prevention of Cardiovascular Disease: A Cross-Sectional Study of Nationally Representative, Individual-Level Data . Global Heart , 19(1): 44
Ebert C, Heesemann E, Vollmer S (2024) Two Scalable Interventions to Promote Health and Mental Development in Early Childhood: A Randomized Controlled Trial in Rural India . Journal of Human Capital , 18(1): 140–193
Diallo AO, Marcus M, Flood D, Theilmann M, Rahim N, Kinlaw A, Franceschini N, Stürmer T, Tien D, Abbasi-Kangevari M, Agoudavi K, Andall-Brereton G, Aryal K, Bahendeka S, Bicaba B, Bovet P, Dorobantu M, Farzadfar F, Ghamari S, Gathecha G, Guwatudde D, Gurung M, Houehanou C, Houinato D, Hwalla N, Jorgensen J, Kagaruki G, Karki K, Martins J, Mayige M, McClure RW, Moghaddam S, Mwalim O, Mwangi K, Norov B, Quesnel-Crooks S, Sibai A, Sturua L, Tsabedze L, Wesseh C, Geldsetzer P, Atun R, Vollmer S, Bärnighausen T, Davies J, Ali MK, Seiglie J, Gower E, Manne- Goehler J (2024) Multiple Cardiovascular Risk Factor Care in 55 Low- and Middle-Income Countries: A Cross-Sectional Analysis of Nationally-Representative, Individual-Level Data from 280,783 Adults . PLOS Global Public Health , 4(3): e0003019
Stein D, Reitsma M, Geldsetzer P, Agoudavi K, Aryal K, Bahendeka S, Brant L, Farzadfar F, Gurung M, Guwatudde D, Houehanou C, Malta D, Soares Martins J, Moghaddam S, Mwangi KJ, Norov B, Sturua L, Zhumadilov Z, Bärnighausen T, Davies J, Flood D, Marcus M, Theilmann M, Vollmer S, Manne-Goehler J, Atun R, Sudharsanan N, Verguet S (2024) Hypertension care cascades and reducing inequities in cardiovascular disease in low- and middle-income countries . Nature Medicine , 30: 414–423
Ghalichi L, Goodman-Palmer D, Whitaker J, Abio A, Wilson M, Wallis L, Norov B, Aryal K, Carvalho Malta D, Bärnighausen T, Geldsetzer P, Flood D, Vollmer S, Theilmann M, Davies J (2024) Individual characteristics associated with road traffic collisions and healthcare seeking in Low- and Middle-Income Countries and territories . PLOS Global Public Health , 4(1): e0002768
Lemp J, Bommer C, Xie M, Michaelik F, Jani A, Davies J, Bärnighausen T, Vollmer S, Geldsetzer P (2023) Quasi-experimental evaluation of a nationwide diabetes prevention programme . Nature , 624: 138–144
Mittal N, Steinert J, Vollmer S (2023) COVID-19 pandemic, losses of livelihoods and uneven recovery in Pune, India . Humanities and Social Sciences Communications , 10: 852
Grafenstein L, Kumar A, Kumar S, Vollmer S (2023) Medium-run impacts of iron-fortified school lunch on anemia, cognition, and learning outcomes in India . Oxford Bulletin of Economics and Statistics , 85(6): 1262–1294
Büttner N, Heemann M, De Neve J-W, Verguet S, Vollmer S, Harttgen K (2023) Economic Growth and Childhood Malnutrition in Low- and Middle-Income Countries . JAMA Network Open , 6(11): e2342654
Foster V, Dim JU, Vollmer S, Zhang F (2023) Understanding the Challenge of Decoupling Transport-Related CO2 Emissions from Economic Growth in Developing Countries . World Development Sustainability , 3: 100111
Marcus M, Mahlalela N, Drame N, Rohr J, Vollmer S, Tollman S, Berkman L, Kahn K, Gomez-Olive F, Manne-Goehler J, Bärnighausen T (2023) Home-based HIV testing strategies for middle-aged and older adults in rural South Africa: a randomized controlled trial . AIDS , 37: 2213–2221
Kuhnt J, Hashmi A, Vollmer S (2023) The effect of the WHO Safe Childbirth Checklist on essential delivery practices and birth outcomes: Evidence from a pair-wise matched randomized controlled trial in Pakistan . SSM - Population Health , 24: 101495
Cockburn N, Flood D, Seiglie J, Manne-Goehler J, Aryal K, Karki K, Damasceno A, Atun R, Vollmer S, Bärnighausen T, Geldsetzer P, Mayige M, Hirschhorn L, Davies J (2023) Health service readiness to provide care for HIV and cardiovascular disease risk factors in low- and middle-income countries . PLOS Global Public Health , 3(9): e0002373
Rahim NE, Flood D, Marcus M, Theilmann M, Aung T, Agoudavi K, Aryal K, Bahendeka S, Bicaba B, Bovet P, Diallo AO, Farzadfar F, Guwatudde D, Houehanou C, Houinato D, Hwalla N, Jorgensen J, Kagaruki GB, Mayige M, Wong-McClure R, Larijani B, Moghaddam S, Mwalim O, Mwangi KJ, Sarkar S, Sibai AM, Sturua L, Wesseh C, Geldsetzer P, Atun R, Vollmer S, Bärnighausen T, Davies J, Ali MK, Seiglie JA, Manne-Goehler J (2023) Diabetes risk and provision of diabetes prevention activities in 44 low-income and middle-income countries: a cross-sectional analysis of nationally representative, individual-level survey data . The Lancet Global Health , 11(10): e1576-e1586
Yoo S, Chung G, Bahendeka S, Sibai A, Damasceno A, Farzadfar F, Rohloff P, Houehanou C, Norov B, Karki K, Azangou-Khyavy M, Marcus M, Aryal K, Brant L, Theilmann M, Cífková R, Lunet N, Gurung M, Mwangi J, Mar-tins J, Haghshenas R, Sturua L, Vollmer S, Bärnighausen T, Atun R, Sussman J, Singh K, Moghaddam S, Gu-watudde D, Geldsetzer P, Manne-Goehler J, Huffman M, Davies J, Flood D (2023) Aspirin for Secondary Prevention of Cardiovascular Disease in 51 Low-, Middle-, and High-Income Countries . JAMA , 330(8): 715-724
Noubactep C, Kenmogne-Tchidjo J, Vollmer S (2023) Iron-fortified water: a new approach for reducing iron deficiency anemia in resource-constrained settings . Scientific Reports , 13: 13565
Ochmann S, von Polenz I, Marcus ME, Theilmann M, Flood D, Agoudavi K, Aryal KK, Bahendeka S, Bicaba B, Bovet P, Caldeira Brant LC, Carvalho Malta D, Damasceno A, Farzadfar F, Gathecha G, Ghanbari A, Gurung M, Guwatudde D, Houehanou C, Houinato D, Hwalla N, Jorgensen JA, Karki KB, Lunet N, Martins J, Mayige M, Moghaddam S, Mwalim O, Mwangi KJ, Norov B, Quesnel-Crooks S, Rezaei N, Sibai AM, Sturua L, Tsabedze L, Wong-McClure R, Davies J, Geldsetzer P, Bärnighausen T, Atun R, Manne-Goehler J, Vollmer S (2023) Diagnostic testing for hypertension, diabetes, and hypercholesterolemia in low- and middle-income countries: a cross-sectional study of 994,185 individuals from 57 nationally representative surveys . The Lancet Global Health , 11(9): e1363-e1371
Naeher D, Albanna B, Kumar A, Vollmer S (2023) Household and plot-level survey data on adoption, outcomes, and perceptions of early sown wheat and zero tillage in Northwest India . Scientific Data 10: 516 [Data ]
Kaplan L, Richert K, Hülsen V, Diba F, Marthoenis M, Muhsin M, Samadi S, Susanti S, Sofyan H, Ichsan I, Vollmer S (2023) Impact of the WHO Safe Childbirth Checklist on Safety Culture among Health Workers: A Randomized Controlled Trial in Aceh, Indonesia . PLOS Global Public Health , 3(6): e0001801
Haggenmüller V, Bogler L, Weber A-C, Kumar A, Bärnighausen T, Danquah I, Vollmer S (2023) Smartphone-based point-of-care anemia screening in rural Bihar in India . Communications Medicine , 3: 38
Gregg E, Buckley J, Ali MK, Davies J, Flood D, Mehta R, Griffiths B, Lim L, Manne-Goehler J, Pearson- Stuttard J, Tandon N, Roglic G, Slama S, Shaw J, HPACC Collaborators (2023) Improving health outcomes of people with diabetes: target setting for the WHO Global Diabetes Compact . The Lancet , 401: 1302-1312
Sofyan H, Diba F, Susanti S, Marthoenis M, Ichsan I, Sasmita NR, Seuring T, Vollmer S (2023) The state of diabetes care and obstacles to better care in Aceh, Indonesia: A mixed-methods study . BMC Health Services Research , 23: 271
Zhu J, Manne-Goehler J, Agarwal A, Bahendeka S, Damasceno A, Marcus M, Moghaddam S, Vollmer S, Huffman M, Flood D, on behalf of the HPACC Collaboration (2023) Medication Use for Cardiovascular Disease Prevention in 40 Low- and Middle-Income Countries . Journal of the American College of Cardiology , 81(6): 620-622
Ebert C, Vollmer S (2022) Girls unwanted: The role of parents’ child-specific sex preference for children’s early mental development . Journal of Health Economics , 82: 102590
Reuter A, Rogge L, Monahan M, Kachapila M, Morton DG, Davies J, Vollmer S on behalf of NIHR Global Surgery Collaboration (2022) The global economic burden of unmet surgical need for appendicitis . British Journal of Surgery , 109(10): 995–1003
Klumpp M, Monfared IG, Vollmer S (2022) Public opinion on global distribution of COVID-19 vaccines: evidence from two nationally representative surveys in Germany and the United States . Vaccine , 40(16): 2457-2461
Steinert J, Vasumati Satish R, Stips F, Vollmer S (2022) Commitment or Concealment? Impacts and Use of a Portable Saving Device: Evidence from a Field Experiment in Urban India . Journal of Economic Behavior & Organization , 193: 367–398
Ochmann S, Owolabi KE, Olatunji-David F, Okunlola N, Vollmer S (2022) The impact of grants in combination with school-based management trainings on primary education: A cluster-randomized trial in Northern Nigeria . Journal of Development Effectiveness , 14(3): 189-208
Heemann M, Kim R, Sharma S, Vollmer S, Subramanian SV (2022) Food group consumption patterns among children meeting and not meeting WHO’s recommended dietary diversity: Evidence from 193,837 Children in 58 countries . Food Policy , 112: 102368
Klumpp M, Monfared IG, Vollmer S (2022) Public opinion towards global distribution of COVID-19 vaccines - Data from Germany and the United States . Scientific Data 9: 583 [Data ]
Theilmann M, Lemp J, Winkler V, Manne-Goehler J, Marcus M, Probst P, Lopez-Arboleda W, Ebert C, Bommer C, Mathur M, Andall-Brereton G, Bahendeka S, Bovet P, Farzadfar F, Ghasemi E, Mayige M, Moghaddam S, Mwangi K, Naderimagham S, Sturua L, Atun R, Davies J, Bärnighausen T, Vollmer S*, Geldsetzer P* (2022) Patterns of tobacco use in low- and middle-income countries by tobacco product and sociodemographic characteristics: a study of nationally representative survey data from 82 countries . The BMJ , 378: e067582 (* joint last authors)
Xu Y, Geldsetzer P, Manne-Goehler J, Theilmann M, Marcus M, Zhumadilov Z, Quesnel-Crooks S, Mwalim O, Saeedi Moghaddam S, Koolaji S, Karki K, Farzadfar F, Ebrahimi N, Damasceno A, Aryal K, Agoudavi K, Atun R, Bärnighausen T, Davies J, Jaacks L, Vollmer S*, Probst C* (2022) The Socio-economic Gradient of Alcohol Use: An Analysis of Nationally Representative Survey Data from 55 Low- and Middle-income Countries . The Lancet Global Health , 10(9): e1268-e1280 (* joint last authors)
Koeppel L, Dittrich S, Miguel S, Carmona S, Ongarello S, Vetter B, Cohn J, Bärnighausen T, Geldsetzer P, Denkinger C, HPACC Collaborators (2022) Addressing the diagnostic gap in hypertension through possible interventions and scale-up: A microsimulation study . PLOS Medicine , 9(12): e1004111
Prenissl J, De Neve J-W, Sudharsanan N, Manne-Goehler J, Mohan V, Awasthi A, Prabhakaran D, Roy A, Tandon N, Davies J, Atun R, Bärnighausen L, Jaacks L, Vollmer S, Geldsetzer P (2022) Patterns of multimorbidity in India: a nationally representative cross-sectional study of individuals aged 15 to 49 years . PLOS Global Public Health , 2(8): e0000587
Kirschbaum T, Sudharsanan N, Manne-Goehler J, De Neve J-W, Lemp J, Theilmann M, Marcus M, Ebert C, Chen S, Yoosefi M, Sibai A, Rouhifard M, Moghaddam S, Mayige M, Martins J, Lunet N, Jorgensen J, Houehanou C, Farzadfar F, Damasceno A, Bovet P, Bahendeka S, Aryal K, Andall-Brereton G, Davies J, Atun R, Vollmer S, Bärnighausen T, Jaacks L, Geldsetzer P (2022) The Association of Socioeconomic Status with Hypertension in 76 Low- and Middle- Income Countries . Journal of the American College of Cardiology , 80(3): 804-817
Flood D, Geldsetzer P, Agoudavi K, Aryal K, Brant L, Brian G, Dorobantu M, Farzadfar F, Fronea O, Gurung MS, Guwatudde D, Houehanou C, Jorgensen J, Kondal D, Labadarios D, Marcus M, Mayige M, Moghimi M, Norov B, Perman G, Quesnel-Crooks S, Rashidi M, Moghaddam S, Seiglie JA, Bahendeka Karaireho S, Steinbrook E, Theilmann M, Ware LJ, Vollmer S, Atun R, Davies JI, Ali MK, Rohloff P, Manne-Goehler J (2022) Rural-Urban Differences in Diabetes Care and Control in 42 Low- and Middle-Income Countries: A Cross-Sectional Study of Nationally Representative, Individual-Level Data . Diabetes Care , 45(9): 1961-1970
Manne-Goehler J*, Theilmann M*, Flood D, Marcus M, Andall-Brereton G, Agoudavi K, Lopez W, Aryal K, Bicaba B, Bovet P, Brant LC, Brian G, Chamberlin G, Chen G, Damasceno A, Dorobantu M, Dunn M, Ebert C, Farzadfar F, Gurung M, Guwatudde D, Houehanou C, Houinato D, Hwalla N, Jørgensen J, Karki K, Labadarios D, Lunet N, Malta D, Martins J, Mayige M, Wong R, Saeedi Moghaddam S, Mwangi K, Mwalim O, Norov B, Quesnel-Crooks S, Rhode S, Seiglie J, Sibai A, Bahendeka S, Sturua L, Stokes A, Supiyev A, Tsabedze L, Zhumadilov Z, Jaacks L*, Atun R*, Davies J*, Geldsetzer P*, Vollmer S*, Bärnighausen T* (2022) Data Resource Profile: The Global Health and Population Project on Access to Care for Cardiometabolic diseases (HPACC) . International Journal of Epidemiology , 51(6): e337–e349 (* equal contribution)
Lemp J, Prasad Nuthanapati M, Bärnighausen T, Vollmer S, Geldsetzer P, Jani A (2022) Use of lifestyle interventions in primary care for individuals with newly diagnosed hypertension, hyperlipidaemia or obesity: a retrospective cohort study . Journal of the Royal Society of Medicine , 115(8): 289-299
Schön M, Heesemann E, Ebert C, Subramanyam M, Vollmer S*, Horn S* (2022) How to ensure full vaccination? The association of institutional delivery and timely postnatal care with childhood vaccination in a cross-sectional study in rural Bihar, India . PLOS Global Public Health , 2(5): e0000411 (* joint last authors)
Marcus M, Manne-Goehler J, Theilmann M, Farzadfar F, Moghaddam S, Keykhaei M, Hajebi A, Tschida S, Lemp J, Aryal K, Dunn M, Houehanou C, Silver B, Rohloff P, Atun R, Bärnighausen T, Geldsetzer P, Ramirez-Zea M, Chopra V, Heisler M, Davies J, Huffman M, Vollmer S*, Flood D* (2022) Use of Statins for the Prevention of Cardiovascular Disease in 41 Low- and Middle-Income Countries: A Cross-Sectional Study of Nationally Representative, Individual-Level Data . The Lancet Global Health , 10(3): e369-e379 (* joint last authors)
Rai RK, De Neve J-W, Geldsetzer P, Vollmer S (2022) Maternal Iron-and-Folic-Acid Supplementation and its Association with Low-birthweight and Neonatal Mortality in India . Public Health Nutrition , 25(3): 623-633
Rai RK, Subramanian SV, Vollmer S (2022) Association of parental characteristics with offspring anthropometric failure, anaemia, and mortality in India . Humanities and Social Sciences Communications , 9: 37
Prenissl J, de Neve J-W, Mohan V, Prabhakaran D, Roy A, Tandon N, Davies JI, Vollmer S, Bärnighausen T, Geldsetzer P (2022) Health system performance for multimorbid cardiometabolic disease in India: a population-based cross-sectional study . Global Heart , 17(1): 7
Purushotham A, Mittal N, Ashwini BC, Umesh KB, von Cramon-Taubadel S, Vollmer S (2022) A quantile regression analysis of dietary diversity and anthropometric outcomes among children and women in the rural–urban interface of Bangalore, India . Food Policy , 107: 102216
Heldring L, Robinson J, Vollmer S (2021) The Long-Run Impact of the Dissolution of the English Monasteries . Quarterly Journal of Economics , 136(4): 2093–2145
Kaplan L, Ichsan, Diba F, Marthoenis, Muhsin, Samadi, Richert K, Susanti S, Sofyan H, Vollmer S (2021) Impact of the World Health Organization Safe Childbirth Checklist on Quality of Care and Birth Outcomes in Aceh, Indonesia: A Cluster-Randomized Clinical Trial . JAMA Network Open , 4(12): e2137168
Krämer M, Kumar S, Vollmer S (2021) Anemia, diet, and cognitive development: Impact of health information on diet quality and child nutrition in rural India . Journal of Economic Behavior & Organization , 190: 495-523
Krämer M, Kumar S, Vollmer S (2021) Improving Child Health and Cognition: Evidence from a School-Based Nutrition Intervention in India . Review of Economics and Statistics , 103(5): 818–834
Monfared I, Garcia J, Vollmer S (2021) Predictors of patients’ choice of hospitals under universal health coverage: a case study of the Nicaraguan capital . BMC Health Services Research , 21: 1356
Basu S, Yudkin JS, Mezhrahid J, Flood D, Lipska K, Beran D, Brown C, Domainico P, Sibai A, Houehanou C, Labadarios D, Farzadfar F, Seiglie J, Aryal K, Marcus M, Mayige M, Theilmann M, Geldsetzer P, Moghaddam SS, Atun R, Bärnighausen T, Vollmer S, Manne-Goehler J, Davies J (2021) Expanding access to newer medicines for people with type 2 diabetes mellitus in low- and middle-income countries: a microsimulation and price target analysis . The Lancet Diabetes & Endocrinology , 9(12): 825-836
Marcus ME, Ebert C, Geldsetzer P, Theilmann M, Bicaba BW, Andall-Brereton G, Bovet P, Farzadfar F, Gurung MS, Houehanou C, Malekpour M-R, Martins JS, Moghaddam SS, Mohammadi E, Norov B, Quesnel-Crooks S, Wong-McClure R, Davies JI, Hlatky MA, Atun R, Bärnighausen T, Jaacks LM, Manne-Goehler J, Vollmer S (2021) Unmet Need for Hypercholesterolemia Care in 35 Low- and Middle-Income Countries: A Cross-sectional Study of Nationally-representative Surveys . PLOS Medicine , 18(10): e1003841
Heesemann E, Mähler C, Subramanyam MA, Vollmer S (2021) Pregnancy anemia, child health and development: A cohort study in rural India . BMJ Open , 11: e046802
Teufel F, Geldsetzer P, Subramanyam M, Yapa M, De Neve J-W, Vollmer S*, Bärnighausen T* (2021) The effect of bearing and rearing a child on blood pressure: A nationally representative instrumental variable analysis of 444 611 mothers in India . International Journal of Epidemiology , 50(5): 1671-1683 (* joint last authors)
Basu S, Flood D, Geldsetzer P, Theilmann M, Marcus M, Ebert C, Mayige M, Wong-McClure R, Farzadfar F, Moghaddam SS, Agoudavi K, Norov B, Houehanou C, Andall-Brereton G, Gurung M, Brian G, Bovet P, Martins J, Atun R, Bärnighausen T, Vollmer S, Manne-Goehler J, Davies J (2021) Estimated effect of increased diagnosis, treatment, and control of diabetes and its associated cardiovascular risk factors among low-income and middle-income countries: a microsimulation model . The Lancet Global Health , 9(11): e1539-e1552
Kuber A, Reuter A, Geldsetzer P, Chimbindi N, Moshabela M, Tanser F, Bärnighausen T, Vollmer S (2021) The Effect of Antiretroviral Therapy on Body Mass Index and Blood Pressure of Patients with HIV in KwaZulu-Natal, South Africa . Scientific Reports , 11: 14718
Teufel F, Seiglie JA, Geldsetzer P, Theilmann M, Marcus M, Ebert C, Agoudavi K, Andall-Brereton G, Aryal KK, Bicaba BW, Brian G, Bovet P, Dorobantu M, Gathecha G, Gurung MS, Guwatudde D, Msaidié M, Houehanou C, Houinato D, Jorgensen J, Kagaruki GB, Karki KB, Labadarios D, Martins JS, Mayige MT, McClure RW, Mwangi JK, Mwalim O, Norov B, Quesnel-Crooks S, Silver BK, Sturua L, Tsabedze L, Wesseh CS, Stokes A, Essien UR, De Neve J-W, Atun R, Davies JI, Vollmer S, Bärnighausen T, Ali MK, Meigs JB, Wexler DJ, Manne-Goehler J (2021) Body mass index and diabetes risk in 57 low- and middle-income countries: a cross-sectional study of nationally-representative individual-level data . The Lancet , 398: 238-248
Bogler L, Weber A-C, Ntambi J, Kapeu AS, Zagre NM, Ekpini RE, Vollmer S (2021) Health-care seeking for childhood diseases by parental age in Western and Central Africa between 1995 and 2017: A descriptive analysis using DHS and MICS from 23 low- and middle- income countries . Journal of Global Health , 11: 13010
Weber A-C, Kapeu AS, Bogler L, Vollmer S, Ekpini RE, Zagre NM (2021) The wealth gradient in diarrhoea, acute respiratory infections, and malaria in childhood over time: A descriptive analysis using DHS and MICS from Western and Central Africa between 1995 and 2017 . Journal of Global Health , 11: 13009
Simen-Kapeu A, Bogler L, Weber A-C, Ntambi J, Zagre NM, Vollmer S, Ekpini RE (2021) Prevalence of diarrhoea, acute respiratory infections, and malaria over time (1995-2017): A regional analysis of 23 countries in West and Central Africa . Journal of Global Health , 11: 13008
Sagalova V, Vollmer S, Ntambi J, Sodjinou R, Bärnighausen T, Simen-Kapeu A, Zagre NM, Nanama S (2021) Socio-economic predictors of undernutrition and anaemia in adolescent mothers in West and Central Africa . Journal of Global Health , 11: 13007
Le Dain A-S, Sagalova V, Sodjinou R, Tou EH, Ntambi J, Vollmer S, Zagre NM (2021) Levels and trends of adolescent girl’s undernutrition and anemia in West and Central Africa from 1998 to 2017 . Journal of Global Health , 11: 13006
Bommer C, Vollmer S, Zagre NM (2021) Correlates of HIV seropositivity in young West and Central African women: A pooled analysis of 17 Demographic and Health Surveys . Journal of Global Health , 11: 13005
Sagalova V, Nanama S, Zagre NM, Vollmer S (2021) Long-term consequences of early marriage and maternity in West and Central Africa: Wealth, education, and fertility . Journal of Global Health , 11: 13004
Sagalova V, Le Dain A-S, Bärnighausen T, Zagre NM, Vollmer S (2021) Does early childbearing affect utilization of antenatal care services and infant birth weight: Evidence from West and Central African Region . Journal of Global Health , 11: 13003
Sagalova V, Garcia J, Kapeu AS, Ntambi J, Zagre NM, Vollmer S (2021) Socio-economic predictors of adolescent marriage and maternity in West and Central Africa between 1986 and 2017 . Journal of Global Health , 11: 13002
Sagalova V, Garcia J, Bärnighausen T, Ntambi J, Sodjinou R, Zagre NM, Vollmer S (2021) Levels and trends of adolescent marriage and maternity in West and Central Africa, 1986-2017 . Journal of Global Health , 11: 13001
Steinert J, Khan S, Mafara E, Wong C, Mlambo K, Hettema A, Walsh FJ, Lejeune C, Mazibuko S, Okello V, Ogbuoji O, De Neve J-W, Vollmer S, Bärnighausen T, Geldsetzer P (2021) The Impact of Immediate ART Initiation on Patient Healthcare Expenditures: A Stepped-Wedge Cluster-Randomised Trial in Eswatini . AIDS & Behavior , 25: 3194–3205
Kirschbaum T, Theilmann M, Sudharsanan N, Manne-Goehler J, Lemp J, De Neve J-W, Marcus M, Ebert C, Chen S, Aryal KK, Bahendeka SK, Bolormaa N, Damasceno A, Dorobantu M, Farzadfar F, Gurung MS, Guwatudde D, Labadarios D, Moghaddam SS, Webster J, Davies JI, Atun R, Vollmer S, Bärnighausen T, Jaacks LM, Geldsetzer P (2021) Targeting hypertension screening in low- and middle-income countries: A cross-sectional analysis of 1.2 million adults in 56 countries . Journal of the American Heart Association , 10: e021063
Flood D, Seiglie JA, Dunn M, Tschida S, Theilmann M, Marcus M, Brian G, Norov B, Mayige MT, Gurung MS, Aryal KK, Labadarios D, Dorobantu M, Silver BK, Bovet P, Jorgensen J, Guwatudde D, Houehanou C, Andall-Brereton G, Quesnel-Crooks S, Sturua L, Farzadfar F, Moghaddam S, Atun R, Vollmer S, Bärnighausen T, Davies JI, Wexler DJ, Geldsetzer P, Rohloff P, Ramírez-Zea M, Heisler M, Manne-Goehler J (2021) The State of Diabetes Treatment Coverage in 55 Low- and Middle-Income Countries: A Cross-Sectional Study of Nationally Representative, Individual-Level Data in 680,102 Adults . The Lancet Healthy Longevity , 2(6): e340-e351
Harkare HV, Corsi D, Kim R, Vollmer S, Subramanian SV (2021) The impact of improved data quality on the prevalence estimates of anthropometric measures using DHS datasets in India . Scientific Reports , 11: 10671
Sudharsanan N, Theilmann M, Kirschbaum T, Manne-Goehler J, Azadnajafabad S, Bovet P, Chen S, De Neve J-W, Dorobantu M, Ebert C, Farzadfar F, Gathecha G, Singh Gurung M, Jamshidi K, Jorgensen J, Labadarios D, Lemp J, Mwangi J, Saeedi Moghaddam S, Bahendeka S, Zhumadilov Z, Bärnighausen T, Vollmer S, Atun R, Davies J, Geldsetzer P (2021) Variation in the proportion of adults in need of BP-lowering medications by hypertension care guideline in low- and middle-income countries: a cross-sectional study of 1,037,215 individuals from 50 nationally representative surveys . Circulation , 143: 991–1001
Peiris D, Ghosh A, Manne-Goehler J, Jaacks LM, Theilmann M, Marcus M, Zhumadilov Z, Wesseh CS, Tsabedze L, Supiyev A, Sturua L, Silver BK, Sibai AM, Quesnel-Crooks S, Pelam DA, Norov B, Mwangi JK, Mwalim O, Wong-McClure R, Mayige MT, Martins JS, Lunet N, Labadarios D, Karki KB, Kagaruki GB, Jorgensen JM, Hwalla NC, Houinato D, Houehanou C, Msaidié M, Guwatudde D, Gurung MS, Gathecha G, Damasceno A, Bicaba BW, Aryal KK, Andall-Brereton G, Agoudavi K, McKenzie B, Webster J, Atun R, Bärnighausen T, Vollmer S, Davies JI, Geldsetzer P (2021) Cardiovascular disease risk profile and management practices in 45 low-income and middle-income countries: a cross sectional study of nationally representative individual-level survey data from 600,484 adults . PLOS Medicine , 18(3): e1003485
Heemann M, Kim R, Vollmer S, Subramanian SV (2021) Assessment of Undernutrition Among Children in 55 Low- and Middle-Income Countries Using Dietary and Anthropometric Measures . JAMA Network Open , 4(8): e2120627
Lacroze E, Bärnighausen T, De Neve J-W, Vollmer S, Ratsimbazafy RM, Emmrich PMF, Muller N, Rajemison E, Rampanjato Z, Ratsiambakaina D, Knauss S, Emmrich JV (2021) The 4MOTHERS trial of impact of a mobile money-based intervention on maternal and neonatal health outcomes in Madagascar: study protocol of a cluster-randomized hybrid effectiveness-implementation trial . Trials , 22: 725
Chavarría E, Diba F, Marcus ME, Marthoenis, Reuter A, Rogge L, Vollmer S (2021) Knowing versus Doing: Protective Health Behavior against COVID-19 in Aceh, Indonesia . Journal of Development Studies , 57(8): 1245–1266
Full publication list →
Ahmad A, Naeher D, Vollmer S (2026) The Political Economy of Patent Buyouts . RAND Journal of Economics, 57(2): 315-333
Bogetić Ž, Naeher D (2025). Fiscal Pro-Cyclicality Revisited: Global, Regional, and Country-Level Evidence with a Spotlight on MENA . Economic Analysis and Policy , 87: 569–584.
Naeher D, De Lombaerde P, Saber T (2025). Evaluating Accession Decisions in Customs Unions: A Dynamic Machine Learning Approach . International Economics and Economic Policy , 22(1).
Ziulu V, Naeher D (2025, forthcoming). Does Adoption of Zero Tillage Reduce Crop Residue Burning? Evidence from Satellite Remote Sensing and Household Survey Data in India . Applied Economics .
Naeher D, Vollmer S (2024, accepted). General vs. Tailored Information for Technology Adoption: Evidence from a Cluster Randomized Controlled Trial in India . Journal of Development Economics (pre-results track).
Naeher D, Narayanan R, Ziulu V (2024). Cash for Coolers or Sustainable Lighting? Assessing Different Components of a Large-Scale Energy Efficiency Program in Mexico . Journal of Development Studies , 60(4): 479–493.
Bogetić Ž, Naeher D (2024). The Good, the Bad, and the Ugly: New Evidence on Alternative Views of Corruption . Applied Economics , 56(33): 4019–4032.
Naeher D, Narayanan R, Ziulu V (2024). The Relevance of Development Policies to Confront Crisis Situations: World Bank’s Early Response to Covid-19 . Journal of Policy Modeling , 46(5): 847–866.
Bogetić Ž, Naeher D (2024). Corruption and Government Revenue: Evidence of a Non-linear Relationship Driven by Crises . Journal of Applied Economics , 27(1): 1–17.
Saber T, Naeher D, Bendechache M (2024). Intelligent Computational Methods for Economics: Editorial . Expert Systems , 41(2): e13523.
Naeher D (2023). The Social Planning Problem with Costly Information Processing: Towards Understanding Production Decisions in Centralized Economies . Economica , 90(357): 285–314.
De Lombaerde P, Naeher D, Saber T (2023). Regional Economic Integration and Machine Learning: Policy Insights from the Review of Literature . Journal of Policy Modeling , 45(5): 1077–1097.
De Lombaerde P, Naeher D, Saber T (2023). On the Optimal Size and Composition of Customs Unions: An Evolutionary Approach . Computational Economics , 62: 1457–1479.
Naeher D, Narayanan R, Ziulu V (2023). Impacts of Energy Efficiency Projects in Developing Countries: Evidence from a Spatial Difference-in-Differences Analysis in Malawi . Energy for Sustainable Development , 73: 365–375.
Bogetić Z, Naeher D, Narayanan R (2023). Measuring Untapped Revenue Potential in Developing Countries: Cross-Country Frontier and Panel Data Analysis . Journal of Public Finance and Public Choice , 38(1): 89–127.
Naeher D, Narayanan R (2023). Attracting Private Capital for Development: Are Poorer Countries Less Efficient? . International Economics and Economic Policy , 20: 1–26.
Naeher D, Albanna B, Kumar A, Vollmer S (2023). Household and Plot-level Survey Data on Adoption, Outcomes, and Perceptions of Early Sown Wheat and Zero Tillage in Northwest India . Scientific Data , 10(516): 1–5.
Naeher D (2022). Technology Adoption under Costly Information Processing . International Economic Review , 63(2): 699–753.
Naeher D, Schündeln M (2022). The Demand for Advice: Theory and Empirical Evidence from Farmers in Sub-Saharan Africa . World Bank Economic Review , 36(1): 91–113.
He Y, Naeher D (2022). Do Democracies Perform Worse During Pandemics? Evidence from 2020 . Economics Bulletin , 42(3): 1681–1687.
De Lombaerde P, Naeher D, Saber T (2021). Regional Integration Clusters and Optimum Customs Unions: A Machine-Learning Approach . Journal of Economic Integration , 36(2): 262–281.
Naeher D, Narayanan R (2020). Untapped Regional Integration Potential: A Global Frontier Analysis . Journal of International Trade & Economic Development , 29(6): 722–747.
Naeher D (2015). An Empirical Estimation of Asia’s Untapped Regional Integration Potential Using Data Envelopment Analysis . Asian Development Review , 32(2): 178–195.
Full publication list →
Bogler L, Ochmann S, Owolabi KE, Weber A-C, Okunlola JO, Vollmer S (2026) Primary school characteristics in Sokoto State, Nigeria . Scientific Data , 13: 539
Bogler L, Weber A-C, Kumar A, Vollmer S (2026) Iron-Fortified Drinking Water in Anganwadi Centres in Rural India: A Randomized Controlled Trial . Review of Development Economics
Bogler L, Kumar A, Subramanian SV, Vollmer S (2025) Effects of a large-scale participatory learning and action programme in women’s groups on knowledge and behaviour related to pregnancy and childcare: a cluster-randomized controlled trial in Bihar, India . SSM - Population Health , 32: 101880
Bogler L, Vieira B, Andriamasy HE, Rapanjato Z, Vollmer S, Bärnighausen T, Ralisimalala A, Emmrich JV, Knauss S (2025) The Impact of a Mobile Money–Based Intervention on Maternal and Neonatal Health Outcomes in Madagascar: Cluster-Randomized Controlled Trial . JMIR Public Health and Surveillance , 11: e70182
Bogler L, Kumar A, Subramanian SV, Vollmer S (2025) Effects of a participatory learning and action programme in women’s groups on adolescent girls: a cluster-randomized controlled trial in Bihar, India . SSM - Population Health , 31: 101840
Sommer M-L, Bogler L, Subramanian SV, Vollmer S (2025) The impact of a participatory learning and action intervention on unmet need for contraception: a cluster-randomized controlled trial in rural Bihar, India . Reproductive Health , 22: 121
Weber A-C, Bogler L, Vollmer S (2024) Formal vs. informal mathematics: Assessing numeracy with school and market items in a large sample of school-aged children in North-West Nigeria . Economics of Education Review , 102: 102564
Bogler L, Bommer C, Ebert C, Kumar A, Subramanian SV, Subramanyam M, Vollmer S (2024) Effects of a large-scale Participatory Learning and Action Programme in Women’s Groups on Health, Nutrition, Water, Sanitation, and Hygiene: a Cluster-Randomized Controlled Trial in Bihar, India . Journal of Development Effectiveness , 16(2): 246–263
Haggenmüller V, Bogler L, Weber A-C, Kumar A, Bärnighausen T, Danquah I, Vollmer S (2023) Smartphone-based point-of-care anemia screening in rural Bihar in India . Communications Medicine , 3: 38
Bogler L, Weber A-C, Ntambi J, Kapeu AS, Zagre NM, Ekpini RE, Vollmer S (2021) Health-care seeking for childhood diseases by parental age in Western and Central Africa between 1995 and 2017: A descriptive analysis using DHS and MICS from 23 low- and middle- income countries . Journal of Global Health , 11: 13010
Weber A-C, Kapeu AS, Bogler L, Vollmer S, Ekpini RE, Zagre NM (2021) The wealth gradient in diarrhoea, acute respiratory infections, and malaria in childhood over time: A descriptive analysis using DHS and MICS from Western and Central Africa between 1995 and 2017 . Journal of Global Health , 11: 13009
Simen-Kapeu A, Bogler L, Weber A-C, Ntambi J, Zagre NM, Vollmer S, Ekpini RE (2021) Prevalence of diarrhoea, acute respiratory infections, and malaria over time (1995-2017): A regional analysis of 23 countries in West and Central Africa . Journal of Global Health , 11: 13008
Full publication list →
Rhode S, Rogge L, Marthoenis M, Seuring T, Zufry H, Bärnighausen T, Sofyan H, Manne-Goehler J, Vollmer S (2025) Real-world smartphone-based point-of- care diagnostics in primary health care to monitor HbA1c levels in people with diabetes . Communications Medicine , 5: 37
Manne-Goehler J*, Theilmann M*, Flood D, Marcus M, Andall-Brereton G, Agoudavi K, Lopez W, Aryal K, Bicaba B, Bovet P, Brant LC, Brian G, Chamberlin G, Chen G, Damasceno A, Dorobantu M, Dunn M, Ebert C, Farzadfar F, Gurung M, Guwatudde D, Houehanou C, Houinato D, Hwalla N, Jørgensen J, Karki K, Labadarios D, Lunet N, Malta D, Martins J, Mayige M, Wong R, Saeedi Moghaddam S, Mwangi K, Mwalim O, Norov B, Quesnel-Crooks S, Rhode S, Seiglie J, Sibai A, Bahendeka S, Sturua L, Stokes A, Supiyev A, Tsabedze L, Zhumadilov Z, Jaacks L*, Atun R*, Davies J*, Geldsetzer P*, Vollmer S*, Bärnighausen T* (2022) Data Resource Profile: The Global Health and Population Project on Access to Care for Cardiometabolic diseases (HPACC) . International Journal of Epidemiology , 51(6): e337–e349 (* equal contribution)
Full publication list →
Teufel F, Roddewig P, Marcus M, Theilmann M, Andall-Brereton G, Aryal K, Azadnajafabad S, Bovet P, Dorobantu M, Farzadfar F, Houehanou C, Sibai A, Stokes A, Labadarios D, Gurung M, Jorgensen J, Karki K, Lunet N, Saeedi Moghaddam S, Mwangi KJ, Sturua L, Flood D, Bärnighausen T, Geldsetzer P, Damasceno A, Davies J, Vollmer S, Ali MK, Manne-Goehler J, Bulstra C (2025) National Evidence on Glucose-Lowering Medication Use for Diabetes from 62 Low- and Middle-Income Countries . Nature Communications , 16: 7139
Publications are listed on Mubarak Ayodeji Sulola’ page .
Full publication list →
Bogler L, Ochmann S, Owolabi KE, Weber A-C, Okunlola JO, Vollmer S (2026) Primary school characteristics in Sokoto State, Nigeria . Scientific Data , 13: 539
Bogler L, Weber A-C, Kumar A, Vollmer S (2026) Iron-Fortified Drinking Water in Anganwadi Centres in Rural India: A Randomized Controlled Trial . Review of Development Economics
Weber A-C, Bogler L, Vollmer S (2024) Formal vs. informal mathematics: Assessing numeracy with school and market items in a large sample of school-aged children in North-West Nigeria . Economics of Education Review , 102: 102564
Haggenmüller V, Bogler L, Weber A-C, Kumar A, Bärnighausen T, Danquah I, Vollmer S (2023) Smartphone-based point-of-care anemia screening in rural Bihar in India . Communications Medicine , 3: 38
Bogler L, Weber A-C, Ntambi J, Kapeu AS, Zagre NM, Ekpini RE, Vollmer S (2021) Health-care seeking for childhood diseases by parental age in Western and Central Africa between 1995 and 2017: A descriptive analysis using DHS and MICS from 23 low- and middle- income countries . Journal of Global Health , 11: 13010
Weber A-C, Kapeu AS, Bogler L, Vollmer S, Ekpini RE, Zagre NM (2021) The wealth gradient in diarrhoea, acute respiratory infections, and malaria in childhood over time: A descriptive analysis using DHS and MICS from Western and Central Africa between 1995 and 2017 . Journal of Global Health , 11: 13009
Simen-Kapeu A, Bogler L, Weber A-C, Ntambi J, Zagre NM, Vollmer S, Ekpini RE (2021) Prevalence of diarrhoea, acute respiratory infections, and malaria over time (1995-2017): A regional analysis of 23 countries in West and Central Africa . Journal of Global Health , 11: 13008