The Maule Cohort (MAUCO) is the first prospective population-based cohort of cardiovascular disease (CVD) and cancer in central Chile. The rationale for this cohort is based on the social, environmental and health characteristics of an under-studied rural population at high risk for chronic diseases. ¹ Chile is regarded as a model for social and economic transition in Latin America. Nevertheless, Chile’s progress and economic growth hide persistent inequalities. ² Poverty rates have declined from 38.6% in 1990 to 20.7% in 2017, when a large proportion of the population was still living in poverty based on their education, health care, employment, social security and housing conditions. ^{3, 4} In Chile, as in other Latin American countries, obesity, CVD and cancer have reached epidemic levels, disproportionately affecting people with lower socioeconomic status and overshadowing the national progress. ^{5, 6} Chilean cross-sectional national health surveys held in 2003, 2009 and 2016 revealed high and increasing prevalences of diabetes (6.3%, 9.4%, 12.3%), metabolic syndrome (22.6%, 35.3%, 40.1%) and overweight/obesity (61.0%, 64.4%, 71.0%). ^7–10