Forensic autopsies in a naturalistic setting in Norway: autopsy rates and toxicological findings

Autopsies can give valuable information about the cause of death, and represent an important tool for obtaining valid cause of death statistics. In particular, they may shed light on the circumstances of death in ambiguous and criminal cases. To address the need for information on current autopsy practices, forensic autopsy rates in two counties in Central Norway over the period 2007-2009 were assessed. To investigate toxicological findings that could possibly remain undisclosed without the performance of an autopsy, the impact of alcohol and drugs in forensic autopsy cases from this material was evaluated. The total forensic autopsy rate in this material was 3%. The forensic autopsy rates were low for natural deaths (1%), accidental falls (12%) and the heterogeneous category "other accidents" (21%), relatively high for accidental poisonings (84%), and less than adequate for road traffic accidents (57%). For suicides the forensic autopsy rate was 63%, and for recognized homicides 100%. The total forensic autopsy rate was higher for men than for women (5% vs. 2%), and decreased with age, being 38% in the age group <30 years, 23% in the age group 30-59 years, and 1% in the age group >59 years. Despite that Norwegian legislation and regulations regarding forensic autopsy requests are national, the forensic autopsy rates were generally lower in the county of Nord-Trøndelag than in Sør-Trøndelag, with most striking differences in suicide deaths (11% vs. 91%) and road traffic accidents (46% vs. 67%). This illustrates how autopsy rates, and possibly cause of death registries, might be susceptible to the influence of regional variations in law enforcement, with possible consequences for the quality and validity of cause of death statistics. Of the forensic autopsy cases where toxicological analysis was performed (361 of 364 cases) a total of 71% had positive toxicology results; 12% were positive for alcohol only, 44% were positive for drugs only, and 15% were positive for both alcohol and drugs. The toxicology results suggest that alcohol and drugs are important factors in sudden unexpected deaths, and that a thorough and comprehensive toxicological analysis is called for when investigating these deaths. Mean BAC in alcohol positive forensic autopsy cases was 1.7‰ (median 1.6‰, range 0.29-4.1‰). The average number of substances detected in toxicology positive cases was 2.6 (median 2, range 1-10). The by far most frequently detected classes of substances were (1) benzodiazepines, (2) opioids and (3) alcohol.