OR13-6 Hyperparathyroidism and Abdominal Aortic Calcification in Older African American Women: PODA Trial

Abstract

Background: Abdominal aortic calcification (AAC) detected on lateral vertebral fracture assessment (VFA) images have shown to be independently associated with increased cardiovascular risk and mortality. Vitamin D deficiency and toxicity have also been linked with vascular calcification. Objective: The objective of this study is to determine the natural progression of AAC in older African American (AA) women. We also wanted to evaluate the relationship between bone mineral markers and AAC. Methods: The study of relationship of Physical performance, Osteoporosis prevention with Vitamin D in older African Americans (PODA) is a randomized, double-blind, placebo-controlled 3-year trial examining the effect of vitamin D on bone loss and physical performance in 260 healthy AA women with mean age of 68.2 (65.4-72.5). Serum 25(OH)D levels were maintained above 75 nmol/l in the active group. We studied VFA images and assessed AAC using the Kauppila score(1). The scores were obtained separately for the anterior and posterior walls of L1-4 vertebrae, resulting in a range from 0 to 6 at each vertebral level and 0 to 24 for the total score. We used the antero-posterior severity score (AAC24) to report composite calcification scores and prospectively collected data annually for the PODA study participants over the course of 3 years. AAC24 cut off score of =>5 has shown to be associated with higher (2.4fold) cardiovascular mortality. Results: There were 14.7%(16/109) subjects with presence of AAC (calcification score>0) in the vitamin D group compared to 12.1%(14/116) in the placebo group. Prevalence of extended AAC (AAC24 score>=5) at baseline was 6.4%(7/109) in the vitamin D group and 3.5%(4/116) in the placebo group. At 36 months, the prevalence was 12.7%(9/71) in the vitamin D group and 6.9%(5/73) in the placebo group. The extended calcification scores (AAC24 score >=5) over time were not different in the vitamin D group compared to the placebo group (p-value for time and group interaction was 0.654). We found no association between AAC and serum creatinine, serum calcium, serum 25(OH)D, beta-crosslaps, and bone specific alkaline phosphatase. Interestingly, we found that as PTH increased over time, the odds of calcification (AAC >=5) also increased (p-value for time and PTH interaction was 0.009). Conclusion: Our study showed that a significant positive association exists between PTH and AAC independent of age and treatment group. In contrast to prior observational studies, we found no significant association between vitamin D status and rates of progression of AAC in older AA women.