Ethnic variation in blood pressure among preadolescent children

As part of a study on methods for assessing diet and exercise among 163 3rd to 6th grade students, data were collected on blood pressure, diet, urinary electrolytes, aerobic activity, resting pulse, and body composition. Data were collected on a stratified sample, with almost equal numbers of children of both sexes from 3rd or 4th and 5th or 6th grades; from three ethnicities: Anglo-, Black- and Mexican-American. Three resting blood pressures were obtained using a Hawksley random zero sphygmomanometer. Data analytic procedures relied on analyses of variance and covariance to assess differences across design factors in blood pressure, with dietary sodium, resting pulse, body surface area, and energy expended as covariates. No differences were detected across ethnic groups in systolic pressures, but Mexican-American children were shown to have significantly higher diastolic fourth phase pressures than Anglo- or Black-American children. Only the dietary variables differed across ethnic groups, but not in the same pattern. Differences in the covariates did not account for the difference across ethnic groups in diastolic pressures.