The Role of Blood Pressure in Carotid Plaque Incidence: Interactions With Body Mass Index, Age, and Sex-Based on a 7-Years Cohort Study

Abstract

Background: Although high blood pressure (BP) is a risk factor for carotid plaque, its long-term prognostic value might be underestimated due to its confounding interactions with BMI, age, and gender. Therefore, we conducted a 7-year prospective cohort study to evaluate the prognostic value of BP for the incidence of carotid plaque. Methods: The subjects enrolled in 2011 were free of carotid plaque at baseline and were followed up in 2018. Multivariate Cox proportional-hazards models were used to evaluate the association between BP and carotid plaque incidence. Results: During the follow-up study, the incidence of carotid plaque was 36.5%. The significant positive linear trend showed that subjects with higher BP levels at baseline were more likely to develop carotid plaques at the end. Especially in the female subpopulation, after confounders being adjusted, the carotid plaque was associated with higher BP (adjusted HR 1.52, 95% CI 1.02-2.26), pulse pressure (PP) (adjusted HR 1.15, 95% CI 0.76-1.75), and mean arterial pressure (MAP) (adjusted HR 1.44, 95% CI 1.00-2.08). The adjusted HRs of hypertension, PP, and MAP (HR 27.71, 95% CI 2.27-338.64; HR 14.47, 95% CI 1.53-137.18; HR 9.97, 95% CI 1.29-77.28) were significantly higher after the potential antagonistic interactions between BP categorical indicators and age being adjusted, respectively. Conclusion: High BP indicators might be associated with higher HRs of carotid plaque after adjusting interactions between BP indicators and BMI, age, and gender, which suggests that the incidence of carotid plaque in female adults with high BP indicators might increase significantly with the increase of age.

Keywords: age; blood pressure; carotid arteries; cohort studies; interaction.

Figure 1

Flowchart depicting participant enrollment. Subjects who were between 35 and 74 years of age and had a full follow-up information were eligible for enrollment in the study. Participant aged 75 years or older were excluded (n = 272). All subjects who had insufficient follow-up information (n = 562), missing data (n = 77), or suffering from cardiovascular diseases or carotid plaque (n = 322) at baseline were also excluded.

Figure 2

Age-adjusted risks of carotid plaque incidence based on different blood pressure indicators in women (A–D) or men (E–H). There is a nonlinear correlation in panel G (p for nonlinear = 0.002) and positive linear correlation in other panels (p for trend <0.05). SBP, systolic blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; MAP, mean arterial pressure.