Association Between Thigh Muscle Fat Infiltration and Incident Heart Failure: The Health ABC Study

Background: Excess adiposity is a well-known risk factor for heart failure (HF). Fat accumulation in and around the peripheral skeletal muscle may further inform risk for HF.

Objectives: The purpose of this study was to evaluate the association between intramuscular and intermuscular fat deposition and incident HF in a longitudinal cohort of community-dwelling older adults.

Methods: The associations of intramuscular and intermuscular fat with incident HF were assessed using Cox models among 2,399 participants from the Health ABC (Health, Aging and Body Composition) study (70-79 years of age, 48% male, 40.2% Black) without baseline HF. Intramuscular fat was determined by bilateral thigh muscle density on computed tomography and intermuscular fat area was determined with computed tomography.

Results: After a median follow-up of 12.2 years, there were 485 incident HF events. Higher sex-specific tertiles of intramuscular and intermuscular fat were each associated with HF risk. After multivariable adjustment for age, sex, race, education, blood pressure, fasting blood sugar, current smoking, prevalent coronary disease, and creatinine, higher intramuscular fat, but not intermuscular fat, was associated with higher risk for HF (HR: 1.34 [95% CI: 1.06-1.69]; P = 0.012, tertile 3 vs tertile 1). This association remained significant after additional adjustment for body mass index (HR: 1.32 [95% CI: 1.03-1.69]), total percent fat (HR: 1.33 [95% CI: 1.03-1.72]), visceral fat (HR: 1.30 [95% CI: 1.01-1.65]), and indexed thigh muscle strength (HR: 1.30 [95% CI: 1.03-1.64]). The association between higher intramuscular fat and HF appeared specific to higher risk of incident HF with reduced ejection fraction (HR: 1.53 [95% CI: 1.03-2.29]), but not with HF with preserved ejection fraction (HR: 1.28 [95% CI: 0.82-1.98]).

Conclusions: Intramuscular, but not intermuscular, thigh muscle fat is independently associated with HF after adjustment for cardiometabolic risk factors and other measurements of adiposity.