These factors included radiation treatment, both dose and duration dependent, age over 50, time since radiation >9 years, cardiovascular risk factors (such as diabetes, hyperlipidemia, and smoking), positive human papillomavirus (HPV) status, and the presence of genotyping known as the "TC haplotype in rs662-rs705379 of single nucleotide polymorphisms (SNP) PON1" in NPC. This evidence concerns the gene PON1 and diabetes mellitus.