The Distribution of Rheumatoid Factor and Rheumatoid Arthritis in the Families of Blackfeet and Pima Indians

Abstract

AbstractAn analysis of the distribution of RF and RA among the families of the Pima and Blackfeet Indians has shown evidence of familial aggregation of positive bentonite flocculation tests and RA within a single generation in the Pima tribe. No evidence could be found that these characteristics were determined by hereditary factors. The data suggest that RF (BFT) and possibly RA were determined by environmental factors in the Pima Indians, but no direct evidence of this could be found in the Blackfeet tribe. It is postulated that RF and RA may be determined by environmental factors operating maximally during the period of infancy, childhood or adolescence.