The effects of familial relationships, age, body weight, and diet on blood pressure and the 24 hour urinary excretion of sodium, potassium, and creatinine in men, women, and children of randomly selected families.

Two hundred thirty-three randomly selected families provided a population for studying the effects of familial relationships, age, diet, body weight, and urinary electrolyte excretion on blood pressure. There was a strong familial component for urinary sodium, potassium, and creatinine excretion and for systolic blood pressure. In individuals, age, heart rate, and body weight were independently related to blood pressure. In women, urinary sodium and potassium levels were related to diastolic blood pressure. These individual relationships persisted when age was accounted for but were no longer significant after adjusting for both age and body weight, suggesting that heavier people eat more food, which in our culture means greater sodium intake. In fact, our randomly selected families were eating as much sodium (130 to 170 meq/day) and as little potassium (50 to 70 meq/day) as consumed by Americans several decades ago. Furthermore, this study again documented the rise in blood pressure with age, which may represent the effect of environmental influences on blood pressure over time. The familial aggregation of urinary sodium, potassium, and creatinine excretion, along with the well-established familial aggregation of body weight, emphasizes the importance of the entire family in the treatment and prevention of hypertension.