The Effect of Altitude on Decomposition: Toward an Understanding of the Postmortem Interval in the Rocky Mountain Region.

The heavily populated Denver Metro area, east of the Rocky Mountains has experienced exponential annual population growth since the 2012 legalization of recreational marijuana. Homicide rates have followed suit; the Colorado Bureau of Investigations reports a 14.7% increase in homicide between 2014 and 2015 (last reported date).

The rural Rocky Mountain region of Colorado is a short drive from the metropolitan area and constitutes an ideal location for clandestine body disposal. Park County constitutes 2,211 square miles of rural space primarily populated by farms, ranches, homesteads, and licensed and illegal marijuana grow operations and is representative of adjacent counties. The Park County Coroner’s Office reports that out-of-county residents constitute 22% of its reported deaths.

The estimation of postmortem interval (PMI) is a critical component of medicolegal death investigation. The catalytic potential for each variable involved in decomposition depends on concentration, affinity for coexisting variables within the microenvironment, and the constituent molecular byproducts of human decomposition. There is currently a complete lack of literature pertaining to the rate, trajectory, and pattern of decomposition within a human sample at high-altitude. The proposed principal investigator initiated land acquisition in 2017 for this purpose. In 2018 Park County Commissioners authorized the donation of 40-acres of land designated for use in high-altitude decomposition study. This study proposes longitudinal observation of decomposition at high-altitude (3,000 meters AMSL) within a human sample.

The first step is to accurately describe the sequence of gross morphological changes that occur as the body decomposes at high-altitude. Sixteen bodies will be placed across a two-year study period. The total body score model will be used as a common scale to describe the longitudinal macroscopic rate, pattern, and trajectory of decomposition within a human sample. Of interest are the phenomena that diverge from the expected trajectory, which have been demonstrated within a porcine sample. These data will be used to develop a macroscopic scoring model to better estimate the postmortem interval of human remains decomposing in a high-altitude outdoor setting. The proposed scoring matrix will be tested in the second year within a human cohort. Finally, the scoring model will be assessed against accumulated degree days using a linear mixed effects model to develop a predictive model for the estimation of postmortem interval at high-altitude.

"Note: This project contains a research and/or development component, as defined in applicable law," and complies with Part 200 Uniform Requirements - 2 CFR 200.210(a)(14).

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