Quantitative assessment of abdominal aortic calcification and associations with lumbar intervertebral disc height loss: the Framingham Study.

BACKGROUND CONTEXT

Vascular disease has been proposed as a risk factor for disc height loss (DHL).

PURPOSE

To examine the relationship between quantitative measures of abdominal aortic calcifications (AACs) as a marker of vascular disease, and DHL, on computed tomography (CT).

STUDY DESIGN

Cross-sectional study in a community-based population.

PATIENT SAMPLE

Four hundred thirty-five participants from the Framingham Heart Study.

OUTCOME MEASURES

Quantitative AAC scores assessed by CT were grouped as tertiles of "no" (reference), "low," and "high" calcification. Disc height loss was evaluated on CT reformations using a four-grade scale. For analytic purposes, DHL was dichotomized as moderate DHL of at least one level at L2-S1 versus less than moderate or no DHL.

METHODS

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).

RESULTS

In crude analyses, low AAC (odds ratio [OR], 2.05 [1.27-3.30]; p=.003) and high AAC (OR, 2.24 [1.38-3.62]; p=.001) 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, 1.20 [0.69-2.09]; p=.51) and high AAC (OR, 0.74 [0.36-1.53]; p=.42).

CONCLUSIONS

Abdominal aortic calcification 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.