Skeletal frailty at Kałdus, a medieval Poland early Piast dynasty cemetery

The objective of this project is to assess skeletal frailty, as estimated using a skeletal frailty index (SFI), at the medieval Polish site of Kałdus to better evaluate the impacts of living and social environments on individuals within this urban­izing population. We assessed biological frailty in adults from the Global History of Health Project database. 11 skeletal and dentoalveolar biomarkers were selected as representative of childhood and adulthood frailty and aggregated into an SFI by summing their occurrence in each individual. Cumulative skeletal frailty scores were tabulated for each individ­ual and could range from 0 (no skeletal markers of stressors present) to 11 (all skeletal markers of stressors present) based on the presence or severity of lifetime stressors that altered their living bones. As many skeletal frailty markers correlate with age, SFIs were compared between individuals within specific age groups: 18–25 (n = 21), 26–35 (n = 31), 36–45 (n = 31), and >45 (n = 25) years. In the overall sample, SFI averaged 4.13 (range 0–9, sd = 1.98). Among males (n = 56), SFI averaged 4.45 (sd = 1.90; range 1–8); among females (n=52), it was 3.79 (sd = 2.03; range 0–9). SFI was lowest in the youngest age group, 2.38 (sd = 1.83; range 0–6) and highest in the oldest, 5.48 (sd = 1.50; range 2–9; p < 0.001). In these medieval skeletons, SFI distributions were significantly different between males and females only when accounting for age (p = 0.044), with females exhibiting higher mean frailty within each age group. Skeletal frailty, as estimated from biomarkers of skeletal stress, suggests these individuals were exposed to considerable stress throughout their lives. As Poland’s written history in the medieval period is sparse, assessing skeletal frailty provides an alternative way to under­stand the lives and experienced stressors of its inhabitants. Further research connecting skeletal frailty to burial context and isotopic evidence will illuminate connections of SFI with diet, lifestyle, and health in medieval Poland.