Inverse relationship between the body mass index and severity of carotid siphon calcifications (another obesity paradox): Results from the Atahualpa Project

Background and aims The importance of the obesity paradox in the intracranial vasculature has not been explored. We assessed whether the body mass index (BMI) correlates with severity of carotid siphon calcifications (CSC) in community-dwelling adults. Methods Using a population-based study design, Atahualpa residents aged ≥40 years underwent head computed tomography (CT) for assessment of CSC. We evaluated the association between BMI and severity of CSC (dependent variable) using regression models adjusted for demographics and cardiovascular risk factors. Results Of 830 people enrolled in the Atahualpa Project, 651 (78%) were included. Mean BMI was 27.3 ± 5 kg/m², with 39% being overweight and 27% obese. CT revealed high calcium content in the carotid siphon in 25% participants. In an adjusted model, individuals with normal weight had a trend for presenting with more severe CSC than those overweight (p = 0.06), and those ones had significantly more severe CSC than obese participants (p = 0.04). Predictive margins of BMI were higher in individuals with low calcium content in the carotid siphon. A contour plot with Shepard interpolation showed that the paradox disappeared in older individuals and in those with severe obesity, irrespective of age. Conclusions BMI inversely associates with severity of CSC. This paradox is relevant in younger individuals and in those without severe obesity, irrespective of age.