Association between vertebral fractures and coronary artery calcification in current and former smokers in the ECLIPSE cohort

High rate of abdominal aortic calcification in COPD patients and its relationship with musculoskeletal fragility

A very high rate of abdominal aortic calcification was observed in patients with COPD. Vascular calcification severity was associated with older age and lower bone mass at the femur in women.

INTRODUCTION

Osteoporosis, sarcopenia, and cardiovascular disease are frequent comorbidities in COPD. Considering routine x-ray as a simple tool to access vertebral fractures and vascular calcification, the rate and severity of abdominal aortic calcification (AAC) and its association with musculoskeletal outcomes were investigated in COPD patients.

METHODS

Ninety-six COPD patients (44 men and 52 women, 65.8 (51-83) and 64.3 (44-85) years-old, respectively) underwent spirometry, laboratory workout, bone mineral density (BMD) measurements with body composition analysis, and thoracolumbar spine radiography. Vertebral fractures (VFs) and AAC were defined using Genant semiquantitative approach and Kauppila score, respectively.

RESULTS

Densitometric osteoporosis and VFs grades 2-3 were detected in almost 40% and 23% of the participants, respectively. Two-thirds of the participants had AAC ≥ 1 while significant atherosclerotic burden (extended AAC, Kauppila score ≥ 5) was seen in 40.6% of the sample. Women with significant atherosclerotic burden were older (P = 0.044) and had lower femoral neck BMD (P = 0.012) when compared to those with an AAC score < 5. Multivariate logistic regression analyses showed that body fat tended to be associated with increased odds of extended AAC in men (OR = 1.06, 95% CI 0.99-1.13, P = 0.099) while femoral neck BMD (0.01 g/cm²) was found to be significantly associated with extended AAC in women (OR = 0.95, 95% CI 0.92-0.99; P = 0.018).

CONCLUSION

COPD patients present a very high rate of AAC and its extended phenotype. Easily measured by conventional spine radiography, AAC severity in women with COPD is associated with low bone mass at the femoral neck, a surrogate marker for musculoskeletal fragility.

Association of Trabecular Bone Score-Adjusted Fracture Risk Assessment Tool with Coronary Artery Calcification in Women

The trabecular bone score (TBS) was found to be significantly associated with moderate coronary artery calcification (CAC). The aim of this study was to further explore the association between TBS-adjusted Fracture Risk Assessment Tool (FRAX) and CAC score in women. The electronic medical record database of a regional teaching hospital in southern Taiwan yielded women who received both coronary computed tomography and bone mineral density (BMD) measurement during their general health examination. Health history, anthropomorphic measurements, laboratory results, BMD, and T-scores were obtained. TBS values were calculated from database spine dual-energy X-ray absorptiometry files. Linear regression analyses tested the association between CAC score and 10-year probability of major osteoporotic fracture (MOF) and hip fracture (HF) determined by TBS-adjusted FRAX. Of the 116 women (mean age 55.8 years) studied, 24.1% had osteoporosis. Simple linear regression showed a significant association of CAC score with an increase in MOF and HF risk as measured by TBS-adjusted FRAX. In multiple linear regression adjusted for potential confounders, CAC score remained significantly associated with TBS-adjusted FRAX for right MOF (p = 0.002), left MOF (p = 0 006), right HF (p = 0.005), and left HF (p = 0.015). In conclusion, clinicians should be vigilant to the potential increased risk of coronary events among women with increased TBS-adjusted FRAX for MOF and HF.

IRF2BP2 3'UTR Polymorphism Increases Coronary Artery Calcification in Men

Interferon regulatory factor 2 binding protein 2 (IRF2BP2) suppresses the innate inflammatory response of macrophages. A 9-nucleotide deletion (rs3045215) in the 3' untranslated region (3'-UTR) of human IRF2BP2 mRNA confers risk of coronary artery disease (CAD) in the Ottawa Heart Genomics Study (OHGS). Here, we sought to identify regulatory mechanisms that may contribute to this risk. We tested how lipopolysaccharides (LPS) affects IRF2BP2 expression in human THP-1 macrophages and primary aortic smooth muscle cells (HAoSMC) genotyped for the deletion allele. Both cell types are implicated in coronary atherosclerosis. We also examined how the deletion affects interaction with RNA binding proteins (RBPs) to regulate IRF2BP2 expression. LPS altered allele-specific binding of RBPs in RNA gel shift assays with the THP-1 macrophage protein extracts. The RBP ELAVL1 suppressed the expression of a luciferase reporter carrying the 3'UTR of IRF2BP2 with the deletion allele. Other RBPs AUF1 or KHSRP did not confer such allele specific regulation. Since it is co-inherited with a risk variant for osteoporosis, a condition tied to arterial calcification, we examined the association of the deletion allele with coronary artery calcification in individuals who had undergone computed tomography angiography in the OHGS. In 323 individuals with a minimal burden of atherosclerosis (<30% coronary stenosis) and 138 CAD cases (>50% stenosis), Mendelian randomization revealed that the rs3045215 deletion allele significantly increased coronary artery calcification in men with minimal coronary stenosis. Thus, not only does the rs3045215 deletion allele predict atherosclerosis, but it also predisposes to early-onset calcification in men.