Systolic Blood Pressure Slope Research Articles

Findings of the International Cooperative INTERSALT Study.

INTERSALT, an international cooperative study on electrolytes and other factors related to blood pressure, found, in within-population analyses involving 10,079 persons, a significant positive association between 24-hour urinary sodium excretion and systolic blood pressure and between the sodium/potassium ratio and systolic blood pressure. These significant findings were derived from analyses for individuals from all 52 centers and from the 48 centers remaining when persons from four low sodium centers were excluded. Potassium excretion of individuals was significantly and independently related inversely to their systolic blood pressure. For men and women, both separate and combined, the relation between sodium and systolic blood pressure was stronger for older than younger adults, perhaps reflecting the result of longer exposure with age or diminished capacity to handle a sodium load. Relations between electrolyte excretion and diastolic blood pressure in individuals were weaker than for systolic blood pressure. Body mass index and heavy alcohol consumption of individuals were strongly and independently related to blood pressure. In cross-population analyses with n = 52 or n = 48, sample median sodium excretion was significantly and independently related to the slope of systolic blood pressure and diastolic blood pressure with age. Other ecological analyses yielded inconsistent results. Four isolated populations showed low sodium excretion, low sodium/potassium excretion, low body mass index, and low alcohol consumption; sample median blood pressures were low, there was little or no upward slope of blood pressure with age, and high blood pressure was rare or nonexistent.

Sodium and potassium intake and blood pressure change in childhood.

To assess the association between sodium and potassium intake and the rise in blood pressure in childhood. Longitudinal study of a cohort of children with annual measurements during an average follow up period of seven years. Epidemiological survey of the population of a suburban town in western Netherlands. Cohort of 233 children aged 5-17 drawn at random from participants in the population survey. At least six annual timed overnight urine samples were obtained. The mean 24 hour sodium and potassium excretion during the follow up period was estimated for each participant and the sodium to potassium ratio calculated. Individual slopes of blood pressure over time were calculated by linear regression analysis. No significant association was observed between sodium excretion and the change in blood pressure over time. The mean systolic blood pressure slopes, however, were lower when potassium intake was higher (coefficient of linear regression -0.045 mm Hg/year/mmol; 95% confidence interval -0.069 to -0.020), and the change in systolic pressure was greater when the urinary sodium to potassium ratio was higher (0.356 mm Hg/year/unit; 95% confidence interval 0.069 to 0.642). In relation to potassium this was interpreted as a rise in blood pressure that was on average 1.0 mm Hg (95% confidence interval -1.65 to -0.35) lower in children in the upper part of the distribution of intake compared with those in the lower part. The mean yearly rise in systolic blood pressure for the group as a whole was 1.95 mm Hg. Urinary electrolyte excretion was not associated with diastolic blood pressure. Dietary potassium and the dietary sodium to potassium ratio are related to the rise in blood pressure in childhood and may be important in the early pathogenesis of primary hypertension.

Twenty-four-hour ambulatory blood pressure in shift workers.

Blood pressure and heart rate of 15 male shift workers were measured every 15 minutes for 24 hours during three work shifts: morning, 4:00 AM to noon; afternoon, noon to 8:00 PM; and night, 8:00 PM to 4:00 AM. For each shift, 24-hour systolic and diastolic blood pressure showed a large "trough" (the low pressure span) and a continuous range of elevated pressure (the high pressure span). Fourier series were used to model the 24-hour blood pressure profiles. A careful examination of the residuals (measured minus predicted pressures) showed that four harmonics were necessary to describe the data accurately. The model enabled localization in each blood pressure profile of the high and low pressure spans that did not coincide with the subject's work and rest periods. The time and slope of blood pressure entering and leaving these spans could also be individually determined. Mean blood pressure during the high pressure span was the same for the three shifts, but mean blood pressure during the low pressure span was lower when the subject worked in the afternoon. During that shift, the systolic blood pressure slopes entering and leaving the low pressure span were steeper than during the two other shifts. The high pressure span was longest during the night shift and shortest during the afternoon shift. Therefore, a change in the working time profoundly perturbed the 24-hour blood pressure profile.(ABSTRACT TRUNCATED AT 250 WORDS)