Factors associated with methamphetamine use in Japanese people who died of unnatural causes: Analysis using forensic autopsy reports.

This study aimed to examine factors related to methamphetamine use in Japanese people who died of unnatural causes. This study used a cross-sectional design. A total of 3343 forensic autopsy reports were obtained from two forensic medicine departments in the Kanto region of Japan. We classified the decedents who underwent forensic autopsies into methamphetamine/amphetamine (MA) and undetected (comparison) groups based on toxicological examination. We matched the decedents in the MA group with those in the comparison group at a 1:4 ratio based on sex and age. The variables, including gang members, criminal records, tattoos, body mass index, infections, concurrent psychotropic drug use, and cause of death, were compared between the groups. Of the 3343 decedents, we matched 109 in the MA group with 436 in the comparison group. Methamphetamine use was significantly associated with gang membership (13.8% vs. 3%, p < 0.001), criminal records unrelated to methamphetamine (47.7% vs. 13.8%, p < 0.001), tattoos (29.2% vs. 6.4%, p < 0.001), and hepatitis C virus infection (48.0% vs. 3.6%, p < 0.001). One-third of the patients in the MA group died from poisoning. This is the first study to show the physical and social characteristics associated with methamphetamine use in Japanese people who died of unnatural causes. Our results could be extended to people with methamphetamine use disorder at risk of death and enable the development of policies and practices to provide necessary intervention in a timely manner.