Demographic, dietary, life style, and anthropometric correlates of blood pressure.

The relationships between systolic and diastolic blood pressure, and select demographic, dietary, life-style, and anthropometric variables were examined for a specialized sample of 10,419 adults, 18 years and over, from the National Health and Nutrition Examination Survey (NHANES) I conducted in 1971-1974. The bivariate relationships of blood pressure to each of the measurements above were examined using zero-order correlation coefficients, and Step-wise linear regression. Age and body mass index (BMI) played a major role in accounting for most of the variance in blood pressure. These two indices alone accounted for 94.5% and 89.0% of the variance in systolic and diastolic blood pressure. In contrast, only 5.5% and 11.0% of the changes in systolic and diastolic blood pressure were explained by all other variables combined. Diet explained less than 1% of the total variance observed for blood pressure for whites, and less than 5% for nonwhites. Select dietary variables such as sodium/potassium ratio, calories from fat, and % saturated fat were not significantly (p less than 0.001) correlated to blood pressure. On the other hand, food calcium, sodium/calcium ratio, food vitamin C, and calcium/phosphorus ratio were significantly correlated to both systolic and diastolic blood pressure.