Epidemiologic studies have demonstrated associations between vascular disease and spinal degeneration. We sought to examine whether vascular disease was associated with lumbar spine facet joint osteoarthritis (FJ OA) in a community-based population.
441 participants from the Framingham Heart Study multi-detector computed tomography (MDCT) Study were included in this ancillary study. We used a quantitative summary measure of abdominal aortic calcification (AAC) from the parent study as a marker for vascular disease. AAC was categorized into tertiles of 'no' (reference), 'low', and 'high' calcification. FJ OA was evaluated on computerised tomography (CT) scans using a four-grade scale. For analytic purposes, FJ OA was dichotomized as moderate FJ OA of at least one joint from L2-S1 vs no moderate FJ OA. We examined the association of AAC and FJ OA using logistic regression before and after adjusting for age, sex and body mass index (BMI). Furthermore, we examined the independent effect of AAC on FJ OA after including the known cardiovascular risk factors; diabetes, hypertension, hypercholesterolemia, and smoking.
Low AAC (OR 3.84 [2.33-6.34]; P<or=0.0001) and high AAC (9.84 [5.29-18.3]; <or=0.0001) were strongly associated with FJ OA, compared with the reference group. After adjusting for age, sex, and BMI, the association with FJ OA was attenuated for both low AAC (1.81 [1.01-3.27]; P=0.05) and high AAC (2.63 [0.99-5.23]; P=0.05). BMI and age were independently and significantly associated with FJ OA. The addition of cardiovascular risk factors to the model did not substantially change parameter estimates for either AAC tertile.
AACs were associated with FJ OA in this community-based population, when adjusting for epidemiologic factors associated with spinal degeneration, and cardiovascular risk factors. Potentially modifiable risk factors for facet degeneration unrelated to conventional biomechanical paradigms may exist. This study is limited by cross-sectional design; longitudinal studies are needed.