Age- and sex-dependent changes of resting amygdalar activity in individuals free of clinical cardiovascular disease

Purpose: Amygdalar metabolic activity was shown to independently predict cardiovascular outcomes. However, little is known about age- and sex-dependent variability in neuronal stress responses among individuals free of cardiac disease. This study sought to assess age- and sex-specific differences of resting amygdalar metabolic activity in the absence of clinical cardiovascular disease.

Methods: Amygdalar metabolic activity was assessed in 563 patients who underwent multimodality imaging by ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography and echocardiography for the evaluation of cardiac function.

Results: After exclusion of 294 patients with structural or functional cardiovascular pathologies, 269 patients (128 women) remained in the final population. ¹⁸F-FDG amygdalar activity significantly decreased with age in men (r = - 0.278, P = 0.001), but not in women (r = 0.002, P = 0.983). Similarly, dichotomous analysis confirmed a lower amygdalar activity in men ≥ 50 years as compared to those < 50 years of age (0.79 ± 0.1 vs. 0.84 ± 0.1, P = 0.007), which was not observed in women (0.81 ± 0.1 vs. 0.82 ± 0.1, P = 0.549). Accordingly, a fully adjusted linear regression analysis identified age as an independent predictor of amygdalar activity only in men (B-coefficient - 0.278, P = 0.001).

Conclusion: Amygdalar activity decreases with age in men, but not in women. The use of amygdalar activity for cardiovascular risk stratification merits consideration of inherent age- and sex-dependent variability.