Obesity, Body Mass Index, and Homicide

The body mass indexes (BMIs) of 100 randomly selected homicide cases from the files of Forensic Science SA were compared to the Australian and South Australian populations. There were 70 males and 30 females (M:F = 2.3:1; age range 18-84 years; mean 42.3 years). There was a substantially lower proportion of obese individuals in the homicide population compared to the general Australian and South Australian populations (19% [vs.] 27.9% and 30%, respectively). A second group of 144 randomly selected autopsy cases where the BMI was ≥40 kg/m² was analyzed. There were 77 males and 67 females (M:F = 1.2:1; age range 23-78 years; mean 46.7 years). The majority of deaths were natural (N = 108), with no homicides. A negative association between obesity and homicide has, therefore, been demonstrated. Reasons for the lower numbers of obese/morbidly obese individuals among homicide victims are unclear, but may include physical protection afforded by fat padding from sharp force injuries, and relative sociodemographic isolation.