Impact of cardiovascular risk factors on premature mortality in Cuba

Abstract Background Cardiovascular diseases are responsible for approximately one-third of all premature deaths in Cuba. However, the relevance of major risk factors, including systolic blood pressure (SBP), diabetes, and body mass index (BMI), for premature cardiovascular mortality in this population remains unclear. Objective To determine the relationship between major cardiovascular risk factors and premature cardiovascular mortality in Cuba. Methods Between 1996 and 2002, 146,556 adults were recruited from the general population in five areas of Cuba. Participants were interviewed, measured (height, weight, and blood pressure), and followed up by electronic linkage to national death registries until January 1, 2017; between 2006 and 2008, 24,345 participants were re-surveyed. After excluding all those with missing data, those with cardiovascular disease at recruitment, and those who died within the first 5 years, Cox regression was used to relate cardiovascular mortality rate ratios (RRs) at ages 35-79 years to smoking, alcohol, systolic blood pressure, diabetes, BMI, and education. RRs were corrected by regression dilution to give associations with long-term average levels of systolic blood pressure and BMI. Results Compared with never smokers, the RR of all-cause mortality at ages 30-69 years for current cigarette smokers was 1.66 (95% CI 1.58-1.74) and was similar in both sexes. Smoking accounted for one-quarter of all premature deaths in this population, but quitting smoking before age 40 years prevented almost all excess mortality. Among regular drinkers, weekly alcohol consumption was positively associated with all-cause mortality. The association was approximately log-linear, with each additional 35cl bottle of rum per week associated with an approximately 10% increased risk of all-cause mortality. Forty percent of all deaths in middle age are caused by tobacco and alcohol. There was a strong inverse association between educational level and premature mortality. Almost one-third of premature deaths were attributable to social inequalities. Cardiovascular mortality was positively associated with SBP, with 20 mmHg more usual SBP almost doubling cardiovascular mortality (RR 2.02, 95% CI 1.88-2.18), diabetes doing so (2.15, 1.95-2.37), and BMI (RR 1.92, 95% 1.64-2.25) with 10 kg/m2 more usual BMI; after adjustment for SBP almost completely attenuated the association of BMI and cardiovascular mortality. Elevated SBP, diabetes and elevated BMI accounted for 27%, 14% and 16% of cardiovascular deaths, respectively. Conclusions This prospective study provides substantial evidence on the effects of major risk factors on premature cardiovascular mortality in Cuba, emphasizing the need for public health interventions targeting these risk factors to reduce the burden of cardiovascular disease in the population.