Inverse association between body mass index and abdominal aortic calcification based on NHANES

The increasing prevalence of obesity worldwide has led to conflicting research on its cardiovascular effects. Although obesity is an established risk factor for cardiovascular disease (CVD), certain evidence indicates that a higher body mass index (BMI) might unexpectedly reduce the risk of vascular calcification. This study was designed to examine the association between BMI and the presence of abdominal aortic calcification (AAC) within a general population. We analyzed data from 3,116 adults participating in the 2013–2014 National Health and Nutrition Examination Survey (NHANES). Severe AAC was diagnosed using the Kauppila score based on dual-energy X-ray absorptiometry (DXA) scans. The relationships between BMI (treated both continuously and categorically) and severe AAC were evaluated using logistic regression. To investigate potential variations and non-linear patterns, subgroup analyses and restricted cubic spline regression were performed. After comprehensive adjustment. higher BMI was significantly associated with lower odds of severe AAC (OR = 0.89, 95% CI: 0.81–0.98, p = 0.013). When compared to individuals with normal weight, obese participants had 62% lower odds of severe AAC (OR = 0.38, 95% CI: 0.16–0.94, p = 0.037). This inverse relationship remained significant in subgroups including males, elderly individuals, and those without hypertension or diabetes. Restricted cubic spline analysis indicated a significant non-linear trend (p for nonlinearity = 0.0023). An inverse association was observed between BMI and AAC prevalence, implying that overweight and obesity may paradoxically confer a protective effect against vascular calcification. These results contribute evidence supporting the existence of an “obesity paradox” in the context of vascular health.