Rib fractures in the Coimbra Identified Skeletal Collection: potential associations with biological sex, age-at-death and bone mineral density

There is a high prevalence of rib fractures in human remains from archaeological contexts, but these are seldom the focus in paleopathological studies pertaining skeletal trauma. This study aims to document rib fracture patterns in the Coimbra Identified Skeletal Collection, Department of Life Sciences, University of Coimbra. Specific aims of this study included the estimation of rib fracture prevalence in 252 individuals, from both sexes (females: 128; males: 124), with age-at-death varying from 20 to 96 years; and the analysis of the relationship between rib fractures andbiological sex, age-at-death, and bone mineral density measured at the proximal femur. The crude prevalence of rib fractures was 6.3% (N=16); while the true prevalence rate was 0.7% (38 fractured ribs in relation to 5656 ribs studied). Males have been more affected than females (males: 10.5%, 13/124; females: 2.3%, 3/128). Individuals with one or more rib fractures were significantly older (mean=66.19 years old; standard deviation [SD]=14.08) than those who have not experienced any rib fracture (mean=50.41 years old; SD=19.45). Low bone mineral density was also associated with the presence of rib fractures but only in females. These results expand the scientific awareness about the prevalence of rib fractures in human skeletal collections.