Twenty-four-hour blood pressure profiles in normotensive sons of hypertensive parents

We investigated whether blood pressures are higher in normotensive offspring of hypertensive parents than in normotensive offspring of normotensive parents outside the physician's office and, if so, whether these higher blood pressures are dependent on the level of dietary sodium intake. We compared 24-hour ambulatory blood pressure profiles between 11 normotensive sons of two hypertensive parents and 11 normotensive sons of two normotensive parents; profiles were recorded after 1 week of a low sodium diet (10 meq/day) and after 1 week of a high sodium diet (200 meq/day). The sons of hypertensive parents were on average 6 years older than the sons of normotensive parents (47±5 [SD] versus 41±4 years, p>0.05). The shift from low to high sodium diet did not significantly change the magnitude of differences in office or ambulatory blood pressures between the groups (i.e., no group-by-diet interaction); thus, we assessed group effects by contrasting blood pressure means for each group pooled across diets. Age-adjusted office blood pressure was higher in sons of hypertensive parents than in sons of normotensive parents (116±7/80±6 versus 111±7/75±6 mm Hg; p=0.020 for systolic and p=0.003 for diastolic blood pressure). The mean for age-adjusted systolic blood pressure was significantly higher in sons of hypertensive parents than in sons of normotensive parents while sons were awake (9 mm Hg higher, p=0.011) but not while asleep (2 mm Hg higher, p=0.494), whereas the mean for age-adjusted diastolic blood pressure was significantly higher in sons of hypertensive parents than in sons of normotensive parents both while sons were awake (10 mm Hg higher, p=0.010) and while asleep (7 mm Hg higher, p=0.0451. This study demonstrates that higher office blood pressures in normotensive offspring of hypertensive parents than in normotensive offspring of normotensive parents reflect persistent differences in blood pressure that are independent of the low (10 meq/day) and high (200 meq/day) dietary sodium intakes imposed for 1-week periods.