Traditional rural dietary pattern and all-cause mortality in a prospective cohort study of elderly Costa Ricans: the Costa Rican Longevity and Healthy Aging Study (CRELES)

BACKGROUND: Costa Rica is experiencing a fast demographic aging. Healthy diets may help to ameliorate the burden of aging-related conditions. OBJECTIVE: This study aimed to investigate the association of a traditional dietary pattern and 2 of its major components (beans and rice) with all-cause mortality among elderly Costa Ricans. METHODS: The Costa Rican Longevity and Healthy Aging Study (CRELES), a prospective cohort study of 2827 elderly Costa Ricans (60+ y at baseline), started in 2004. We used a food frequency questionnaire (FFQ) to assess usual diet. We calculated dietary patterns using principal component analysis. Multivariate energy-adjusted proportional-hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: Over a 15-y follow-up, encompassing 24,304 person-years, 1667 deaths occurred. The traditional Costa Rican dietary pattern was more frequent in rural parts of the country, and it was inversely associated with all-cause mortality. Subjects in the fifth quintile of intake had 18% lower all-cause mortality than those in the first quintile (HR: 0.82; 95% CI: 0.69, 0.98; P-trend = 0.01), particularly among males (HR: 0.73; 95% CI: 0.56, 0.95). Bean intake was associated with lower all-cause mortality among all subjects (HR: 0.79; 95% CI: 0.68, 0.91, highest compared with lowest tertile) and in sex-stratified analysis. Rice consumption was inversely associated with all-cause mortality solely among males (HR: 0.75; 95% CI: 0.60, 0.94, highest compared with lowest tertile). CONCLUSIONS: Our results suggest that a traditional Costa Rican rural dietary pattern is associated with lower all-cause mortality in elderly Costa Ricans. Beans, a major component of this traditional dietary pattern, was also associated with lower all-cause mortality. These findings could have important implications for public health, given the nutritional transition and the reduction of intake of traditional diets in Latin American countries.