Using systematic literature review, van der Maarel-Wierink et al. identified 13 risk factors of AP: age, male sex, lung diseases, dysphagia, diabetes mellitus, dementia, angiotensin I-converting enzyme deletion/deletion genotype, bad oral health, malnutrition, Parkinson’s disease, and the use of antipsychotic drugs, proton pump inhibitors, and angiotensin-converting enzyme inhibitors [9]. The gene discussed is ACE; the disease is diabetes mellitus.