Associations of Abdominal Muscle Area with 4-Year Change in Coronary Artery Calcium Differ by Ethnicity Among Post-Menopausal Women.

Objective: To examine the association of abdominal muscle area with coronary artery calcium (CAC) presence, extent, and progression in a multi-ethnic cohort of older, community-dwelling post-menopausal women.
Design and Setting: Cross-sectional and longitudinal population-based cohort.
Participants: The sample comprised 179 non-Hispanic White women, 116 Filipina women and 144 African American women, all without known CVD, who underwent chest and abdominal computed tomography (CT) scans twice about four years apart for abdominal muscle and fat, as well as CAC.
Main Outcome Measures: CAC presence, extent and progression.
Results: There was a significant interaction of ethnicity with baseline oblique muscle area (p-for-interaction .01), and marginally significant interactions with baseline total and paraspinal muscle for change in CAC (p-for-interactions both .09). Among Filipina women, each standard deviation (SD) greater total muscle area was associated with a 26% (95% CI (-43%, -4%), P=.02) reduced rate of change in CAC; higher paraspinal and oblique muscle area were associated with a 24% (-38%, -6%, P=.01) and a 37% (-53%, -16%, P=.0002) reduced rate of change in CAC, respectively. These associations were not significant in African American or non-Hispanic White women. There were no significant associations of abdominal muscle with CAC presence or extent, nor were there significant ethnicity by muscle interactions in these models.
Conclusions: Among Filipina women, greater abdominal muscle mass is associated with a decreased rate of CAC progression. Higher muscle mass may be important for this group in reducing CVD outcomes.