Modeling the Epidemiologic Transition Study (METS)

METS is a prospective, longitudinal study investigating cardiometabolic health in populations of African origin from rural Ghana, peri urban South Africa, urban Jamaica, urban Seychelles and suburban United States. Leveraging the epidemiologic transition, the METS sites vary several ways including socio-economic development, physical environment, nutrition transition and food systems allowing several factors to be analysed simultaneously. Due to the uniqueness of the cohort, METS has provided invaluable information relating to total energy expenditure, nutrition, physical activity and cardiometabolic health in understudied, marginalized populations, particularly in sub-Saharan Africa.

METS was originally designed to investigate the relationship between physical activity and obesity and cardiometabolic disease risk among African-origin populations spanning the epidemiologic transition. Using a prospective cohort design, the METS study enrolled 500 participants, ages 25-45 years, from each of five African-origin populations, i.e., Ghana, South Africa, Seychelles, Jamaica and the United States between 2009-2010 (baseline). In all participants at baseline PA was measured using accelerometry and dietary intake by 24-hour dietary recalls, fasting glucose/insulin, and adipocytokines were measured by standard laboratory methods, and social and environmental factors, PA patterns and alcohol, smoking and medication histories were assessed by questionnaire. In a random subset of 75 participants from each site at baseline, total energy expenditure was measured using the doubly labeled water (DLW) method and resting energy expenditure by indirect calorimetry. Follow-up measurements of weight, waist circumference and blood pressure were made at 12-months and repeated at 24-months. METS was extended in 2018 as METS-Microbiome, which added a further two time points (2019 and 2022), resulting in over 1600 individuals being followed for over 10 years, and in some cases longer.

By focusing on objectively measured physical activity, METS has made significant contributions to our understanding of the relationship between habitual physical activity and obesity risk. Prior hypotheses focused solely on energy expenditure, mostly through physical activity, as a singular driver of population-level obesity risk. METS established that baseline physical activity levels at the population level are not predictive of future obesity risk, and that the dietary environment, particularly the proliferation of ultra-processed foods among low-middle income countries must be considered when exploring obesity risk. Further, METS contributed its DLW data to the International Atomic Energy Association (IAEA) DLW database, providing over 90% of the data from sub-Saharan Africa.

Project Team:

• Lara R. Dugas – Loyola University Chicago, United States & University of Cape Town, South Africa
• Amy Luke – Loyola University Chicago, United States
• Kweku Bedu-Addo – Kwame Nkrumah University of Science and Technology, Ghana
• Kingsley Apusiga – Kwame Nkrumah University of Science and Technology, Ghana
• Estelle V. Lambert – University of Cape Town, South Africa
• Terrence E. Forrester – University of West Indies, Jamaica
• Pascal Bovet – Ministry of Health, Victoria, Republic of Seychelles
• Jack A. Gilbert – University of Sand Diego, United States
• Brian T. Layden – University of Illinois Chicago, United States
• Candice Choo-Kang – Loyola University Chicago, United States