ACE2 and chronic lung disease: In addition, men appear to suffer more serious illness and possibly higher mortality rates, in part perhaps due to sex differences in angiotensin-converting enzyme 2 (ACE2) receptors, relatively higher contribution of preexisting diseases (i.e., CVD, hypertension, diabetes, and chronic lung disease), higher risk behaviors (i.e., smoking and alcohol use), and occupational exposure (130, 132–137).