Reducing the Risk of Cardiovascular Disease

araphrasing the opening lines of A Tale of Two Cities by Charles Dickens, these are the best of times and the worst of times for patients with cardiovascular diseases (CVDs) around the world.Tremendous achievements have been observed in high-income countries at both population and individual levels.Most high-income countries achieved a population-level decline in CVD mortality of >50% within 1 generation. 1 Rapid advances in cardiovascular care since the 1970s have resulted in a large decline in both out-of-hospital and in-hospital mortality after acute myocardial infarction. 2,3In high-income countries, population-level cardiovascular risk factors have declined substantially. 3 In contrast, CVD burdens have either risen or only slowly declined in low-and middle-income countries during the same period. 3RICS (Brazil, Russia, India, China, and South Africa), a grouping of upper-and lower-middle-income countries, constitutes close to 44% of the world's population, contributes to 32% of the world's gross domestic product, and has a major influence on global economy. 4The large burden of CVDs in BRICS, particularly in younger and productive age groups, can impair national economic development and adversely affect global economy.There is substantial heterogeneity in CVD mortality and risk factors even within this apparently homogenous bloc of emerging economies.Whereas aging of the population has resulted in a high burden of CVD, age-specific CVD mortality rates are highly variable among these countries.This variation is attributable both to the level and calendar of economic growth and the efficiency with which multisectoral prevention policies combined with health care services to reduce CVD risk across the life course are implemented.Temporal trends in CVD mortality and their ecological associations with risk factor levels have been well-documented, but the roles of cohort and period effects have not been equally well studied.Age-period-cohort analyses can yield valuable insights into the successes and challenges that mark the evolution of the CVD epidemic across the BRICS countries and explain the variations in the course of their CVD epidemics.In this issue of Circulation, Zou et al 5 make good use of data from the Global Burden of Disease study to analyze time trends in BRICS countries over 25 years.The authors derive mortality estimates from the 2017 Global Burden of Disease study and use age-period-cohort modeling to estimate cohort and period effects in CVD between 1992 and 2016.Age-period-cohort models are additive models in which the predictor is a sum of 3 time effects: functions of age, period, and cohort. 6Data for these are drawn from repeated cross-sectional surveys, in which the time effects can be combined with individual covariates.Using this sophisticated analytical model, the authors were able to obtain several outcomes to reflect