UC Riverside

The Tiwanaku (AD 500–1100) colonized ecologically diverse, lower elevation areas to produce goods not easily grown in the high altitude heartland (3,800 m a.s.l.). One colony near present-day Moquegua, Peru (900–1,500 m a.s.l.) was composed of multiple Tiwanaku settlements. Colonists farmed products like maize and coca and transported goods via llama caravan between the colony and heartland. Two subsistence groups emerged in terms of settlement, those of “Chen Chen-style” affiliation associated with an agrarian lifestyle and those of “Omo-style” representing more of a pastoralist lifeway. Considering Tiwanaku people likely began light chores around 5 years of age (e.g., babysitting siblings), with heavier labour beginning at approximately 8 years of age, we questioned if these social and occupational differences translated into skeletal changes associated with osteoarthritis (i.e., porosity, lipping, osteophyte formation, and/or eburnation). Individuals from 5 sites, 2 that represent the Omo-style (M16 and M70) and 3 that are in the Chen Chen-style (M1, M10, and M43), were evaluated for osteoarthritis while controlling for age-at-death and sex using 25 total joint surfaces in the shoulder, elbow, wrist, hip, knee, ankle, and sacroiliac. Overall, our comparisons show no combined significant differences between the Omo-style and Chen Chen-style groups. Instead, distinctions in osteoarthritis evidence by age-at-death and sex emerged, reflecting the likelihood of specific age- or sex-related tasks. Arthropathy evidence among children in elbow and ankle joints also supported the cultural legacy in the Andes that work begins at a relatively young age and would show up in patterns of adult osteoarthritis.