Quantitative Assessment of Abdominal Aortic Calcification and Disk Height Loss: The Framingham Study

IntroductionPrior epidemiologic studies have demonstrated associations between vascular disease and spinal degeneration. We sought to characterize the relationship between a quantitative measure of abdominal aortic calcifications (AAC) and disk height loss (DHL) in a community-based population. Design436 participants from the Framingham Heart Study Multi-Detector Computed Tomography (CT) Study were included in this ancillary study. We used a quantitative summary measure of AAC from the parent study as a marker for vascular disease. AAC was categorized into tertiles of ‘no’ (reference), ‘low’, and ‘high’ calcification. DHL was evaluated on CT scans using a 4-grade scale. For analytic purposes, DHL was dichotomized as moderate DHL of at least one level at L2-S1 vs. less than moderate or no DHL. We examined the association of AAC and DHL using logistic regression before and after adjusting for cardiovascular risk factors, and before and after adjusting for age, sex and body mass index (BMI). ResultsIn crude analyses, low AAC (OR 2.20[1.37-3.55]; p=0.0012) and high AAC (OR 2.33[1.44-3.77]; p=0.0006) were strongly associated with DHL, when compared with the reference group of no AAC. Diabetes, hypercholesterolemia, hypertension, and smoking were not associated with DHL, and did not attenuate the observed relationship between AAC and DHL. Adjustment for age, sex, and BMI markedly attenuated the associations between DHL and low AAC (OR 1.34[0.78-2.31]; p=0.29) and high AAC (OR 0.74[0.36-1.51]; p=0.40). ConclusionsAAC was associated with DHL in this community-based population. This relationship was independent of cardiovascular risk factors. However, the association of AAC with DHL was explained by the effects of age, sex, and BMI.