Abstract P228: Abdominal Lean Muscle Mass is Associated with the Density, but Not the Volume, of Coronary Arterial Calcium and Abdominal Aortic Calcium

Abstract

Introduction: Higher volume of coronary arterial calcium (CAC) and abdominal aortic calcium (AAC) are predictive of incident CVD, while higher density of CAC and AAC are associated with lower risk. The purpose of the present study was to determine the associations of abdominal lean muscle mass (ALMM) with CAC volume, CAC density, AAC volume, and AAC density. Hypothesis: We hypothesized that abdominal muscle mass would be negatively associated with CAC and AAC volume but positively associated with CAC and AAC density. Methods: The current study analyzed data from the Multi-Ethnic Study of Atherosclerosis (MESA) in those participants who underwent abdominal computed tomography (CT) to assess for AAC, which was also analyzed for volumes of fat (visceral and subcutaneous) and ALMM (psoas, rectus abdominis, obliques, and paraspinus). CAC and AAC were scored separately, for density and for volume. Results: Analyses were restricted to participants who had non-zero CAC or AAC volumes. The sample sizes for the CAC analyses and AAC analyses were 963 and 1283 subjects, respectively. For the CAC analyses, 39.4% (379 of 963) were female and the mean age was 66.4 years. Mean ± SD CAC volume was 218.52 ± 344.19 (range 2.34- 3244.77 mm 3 ) ; Mean ± SD CAC density was 2.70 ± .72 (range 0.83- 4.0 Hu category units). Mean ± SD AAC volume was 1402.33 ± 1888 (range 4.68- 15822.2 mm 3 ); mean ± SD AAC density was 3.02 ± .63 (range 0.83- 4.0 Hu category units). In multivariable linear regression models that controlled for age, race, gender, CVD risk factors, visceral fat, and liver and kidney markers, both CAC and AAC density were found to be significantly associated with abdominal lean muscle mass. For every 100 cm 2 increase of ALMM, CAC density decreased by .35 Hu category units (p < .05). For every 100 cm 2 increase of ALMM, AAC density decreased by .26 Hu category units (p < .05). Conversely, CAC and AAC volume were not significantly associated with abdominal lean muscle mass in final models. Conclusion: Higher levels of ALMM were associated with lower CAC and AAC density, but not volume. Contrary to expectation, we found an inverse association of ALMM with CAC and AAC density, independent of relevant CVD risk factors.