A Family Study of Blood Pressure in Polynesians

The family aggregation of blood pressure was studied in Tokelau Island children aged 5–14 years and their parents resident on their home islands in 1971. Five hundred and two (97 per cent) of the children had a recorded blood pressure and they formed 210 sibling groups. The sibship similarity of blood pressure z scores adjusted for year of age and sex was examined by analysis of variance between and within sibships in the 133 sibships with more than one member. For both systolic and diastolic pressure a statistically significant sibship similarity exists which is independent of family size, level of pressure, and the sibship similarity of Quetelet Index. The correlation coefficient of the z score of one index child chosen at random and the remaining siblings is 0.14 (n = 282, p = 0.017). Of the parental variables studied the mother's systolic pressure is the best, and only, predictor of the child's systolic z score. These results suggest that in the Tokelau Islanders a family similarity of blood pressure is established relatively early in life.