Blood pressure levels of the Suruí and Zoró Indians of the Brazilian Amazon: group- and sex-specific effects resulting from body composition, health status, and age

Two related Tupí-Mondê-speaking tribes of the Aripuan? Indian Park of western Brazil are compared in terms of their recent contact with Western culture, subsistence patterns, general health, and blood pressure levels. Age, weight, height, sex, and tribal affiliation for Suruí and Zoró adults over age 18 are included in an analysis of covariance to test regression models of both diastolic and systolic blood pressure. Because of significant interaction effects between sex and other covariates, sex-specific models were developed. The relationship between body mass and blood pressure level in males conforms with Western data, but the direction and magnitude of effects for the age and body mass covariates in both sexes conflict with data from other modernizing societies. With age, weight/height ratio, and sex differences controlled for, Suruí males show a lower mean systolic blood pressure (SBP) level and diastolic blood pressure (DBP) level than Zoró males. Intertribal differences were smaller among females: Suruí females SBP and DBP differences were similar but did not reach significance. Other sex-specific differences include a greater inverse relationship between age and SBP level among the 104 male subjects than among the 98 female subjects (with similar trends in DBP) and a small but significant effect of the weight/height ratio on both SBP and DBP in males but not in females. Health status data for these groups suggest that hypothesized increases in mean blood pressure levels following the Suruí's acceptance of a Western diet and social stratification may be modified by their health status, particularly prevalent infectious disease.