Risk factors, cardiovascular disease, and mortality in South America: a PURE substudy

In a multinational South American cohort, we examined variations in CVD incidence and mortality rates between subpopulations stratified by country, by sex and by urban or rural location. We also examined the contributions of 12 modifiable risk factors to CVD development and to death.

This prospective cohort study included 24 718 participants from 51 urban and 49 rural communities in Argentina, Brazil, Chile, and Colombia. The mean follow-up was 10.3 years. The incidence of CVD and mortality rates were calculated for the overall cohort and in subpopulations. Hazard ratios and population attributable fractions (PAFs) for CVD and for death were examined for 12 common modifiable risk factors, grouped as metabolic (hypertension, diabetes, abdominal obesity, and high non-HDL cholesterol), behavioural (tobacco, alcohol, diet quality, and physical activity), and others (education, household air pollution, strength, and depression). Leading causes of death were CVD (31.1%), cancer (30.6%), and respiratory diseases (8.6%). The incidence of CVD (per 1000 person-years) only modestly varied between countries, with the highest incidence in Brazil (3.86) and the lowest in Argentina (3.07). There was a greater variation in mortality rates (per 1000 person-years) between countries, with the highest in Argentina (5.98) and the lowest in Chile (4.07). Men had a higher incidence of CVD (4.48 vs. 2.60 per 1000 person-years) and a higher mortality rate (6.33 vs. 3.96 per 1000 person-years) compared with women. Deaths were higher in rural compared to urban areas. Approximately 72% of the PAF for CVD and 69% of the PAF for deaths were attributable to 12 modifiable risk factors. For CVD, largest PAFs were due to hypertension (18.7%), abdominal obesity (15.4%), tobacco use (13.5%), low strength (5.6%), and diabetes (5.3%). For death, the largest PAFs were from tobacco use (14.4%), hypertension (12.0%), low education (10.5%), abdominal obesity (9.7%), and diabetes (5.5%).

Cardiovascular disease, cancer, and respiratory diseases account for over two-thirds of deaths in South America. Men have consistently higher CVD and mortality rates than women. A large proportion of CVD and premature deaths could be averted by controlling metabolic risk factors and tobacco use, which are common leading risk factors for both outcomes in the region.