Greater Central Adiposity Is Associated With Poorer Left Atrial Function: The Atherosclerosis Risk in Communities...

To evaluate the association of longitudinal change in waist circumference (WC), waist-to-hip ratio (WHR), and body mass index (BMI) with left atrial (LA) function in the Atherosclerosis Risk in Communities study, a community-based cohort study.

We included 4008 participants (mean age, 75.1 years; 59% female; 20% Black) with 2D speckle-tracking echocardiographic LA strain data and without prevalent heart failure or atrial fibrillation at visit (V)5. Measures of adiposity were obtained at V4 (1996-1998) and V5 (2011-2013). We categorized change in WC, BMI, or WHR from V4 to V5 as consistently low (reference group), consistently elevated, increasing, and decreasing. Multivariable linear regression was used to evaluate the association of change in adiposity with LA function.

Participants with consistently elevated WC from V4 to V5 had the lowest mean LA reservoir (32.4%) and conduit function (14.4%). Compared with consistently low WC, increasing WC and consistently elevated WC were significantly associated with worse LA reservoir function (β, -0.90; 95% CI, -1.61 to -0.18, and β, -1.00; 95% CI, -1.56 to -0.44, respectively) and conduit function (β, -0.66; 95% CI, -1.22 to -0.10, and β, -1.02; 95% CI, -1.46 to -0.58, respectively), after adjusting for cardiovascular disease risk factors, physical activity, LV size and function, and LA size. Similarly, compared with consistently low WHR, consistently elevated WHR was significantly associated with worse LA reservoir (β, -1.00; 95% CI, -1.61 to -0.39) and conduit functions (β, -1.16; 95% CI, -1.64, -0.69). Compared with consistently low BMI, consistently elevated BMI was associated with significantly lower LA reservoir function (β, -0.66; 95% CI, -1.20 to -0.12). Change in WC, WHR, and BMI were not associated with LA contractile function.

Worsening central adiposity from mid-life to late life is associated with reduced LA reservoir and conduit function, independent of LA size and LV size and function. This finding underscores the key role that consistently low adiposity might play in preventing atrial myopathy.