Reed, D. (School of Public Health, Univ. of Texas, P. O. Box 20186, Astrodome Station, Houston, Texas 77025), D, Labarthe and R. Stallones. Health effects of westernization and migration among Chamorros. Amer. J. Epid., 1970, 92: 94–112.—This study is an epidemiobgic exploration of the relationship between disease and sociocultural discontinuity among three groups of Chamorro natives of the Mariana Islands. Although similar in genetic background, the three groups have had different sociocultural experiences by virtue of their residence on Rota, Guam and California. As a test of the hypothesis that migration and westernization are associated with an increased prevalence of a variety of diseases among adult Chamorros, we examined over 1, 200 individuals. A 24-hour dietary survey was completed for a subsample in each area, and 10-year mortality data were obtained in Guam and California. The results documented the differences of the three groups in terms of migration, mobility and sociocultural orientation. The prevalence of disease characteristics was not consistent among the areas, but followed several patterns. Geographic analysis showed that the frequencies of the most specific measures of disease, except for those related to coronary heart disease, were similar in all three areas. Analysis of sociocultural and illness variables, as characteristics of individuals independent of geographic area, failed to show association of any disease variable with any measure of mobility or sociocultural orientation.