M.A. Theses: Jacqueline M. Dale, 1994

Cribra Orbitalia, Nutrition and Pathogenic Stress in Prehistoric Skeletal Remains from the Pender Island Canal Sites (DeRt 1, DeRt 2), British Columbia, Canada

The presence of cribra orbitalia in prehistoric skeletal material is usually cited as an indicator of dietary stress. It is identified by porous opening of various size and frequency in the orbital roof of an affected skull. There is strong evidence to suggest that the orbital lesions are formed during a childhood episode of anemia. The dietary explanation, however, has never been completely accepted for the occurrence of cribra orbitalia on the Northwest Coast where the diet appears to have been iron-rich. Recent research suggests that iron deficiency may be more closely related to infection and pathogenic stress than to diet. Lowered iron levels are a natural defense the body employs against infection. If the body fails to maintain a balance between lowered iron levels as a defense and increased physiological needs, iron deficiency anemia will ensue.

This research provides an analysis of cribra orbitalia in a sample of 83 prehistoric crania from the Pender Island Canal Sites (DeRt 1, DeRt2) on North Pender Island, in the Gulf Islands of British Columbia. The sample is examined for the presence and severity of cribra orbitalia. Statistical analysis is used to identify patterns of occurrence by sex, age, and time period. These data provide a basis for examining both the traditional dietary model, and the alternative pathogenic stress model.

Prehistoric diet is estimated through archaeological, ethnographic, stable carbon isotopic, and botanical evidence. Nutritional adequacy is estimated through a literature-based nutritional analysis of traditional foods. Potential environmental pathogens are identified by using archaeological, ethnographic, and modern clinical evidence.

The results of this study indicate a high prevalence of cribra orbitalia in the Pender Canal skeletal sample. Dietary and pathogenic data suggest that pathogenic stress best explains the high occurrence of cribra orbitalia at Pender Canal. It is proposed that conditions associated with aggregation and sedentism at the site are responsible for the high prevalence. Inadequate sanitation, crowded living conditions, and contaminated water sources probably provided ideal conditions for pathogen growth and transmission. Children would be particularly susceptible to iron deficiency anemia at weaning because of increased pathogen exposure, low iron stores, and high growth demands.