Carotid intima-media thickness and incident hypertension: the Brazilian Longitudinal Study of Adult Health

Background: High blood pressure (BP) increases carotid intima-media thickness (CIMT). On the other hand, it is not clear whether the vascular abnormalities reflected in high CIMT may predict incident hypertension. The present study aims to investigate the association between CIMT and incident hypertension after 4 years of follow-up in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multiethnic sample of middle-aged adults from six Brazilian cities. Methods: We analyzed data from 6682 ELSA-Brasil participants (aged 35-74) without hypertension and with complete CIMT data at baseline. After 4 years of follow-up, we describe hypertension incidence, stratifying the sample according to age, sex, and race-specific CIMT quartiles. We also built crude and adjusted Poisson regression models to analyze the association between mean and maximal CIMT values and incident hypertension. Results: We found incident hypertension in 987 (14.8%) participants. According to mean CIMT quartile groups, hypertension incidence varied from 10.2% (first quartile group) to 22.4% (fourth quartile group; P for trend <0.001). In fully adjusted models, 0.1 mm increments in mean CIMT values were associated with a 16% [relative risk (RR):1.16; 95% confidence interval (95% CI) 1.10-1.21; P < 0.001] higher risk of incident hypertension, respectively. Results were similar when maximal CIMT values were considered instead of mean CIMT values. Conclusion: CIMT values at baseline strongly predicted incident hypertension after 4 years of follow-up in this large multiethnic cohort. This highlights the relationship between CIMT and BP and may provide important insights into the significance of this ultrasound measurement.