24-H AMBULATORY BLOOD-PRESSURE IN 352 NORMAL DANISH SUBJECTS, RELATEDTO AGE AND GENDER

This study was conducted to determine age and sex stratified normal va lues for 24-h ambulatory blood pressure. A sample of 352 healthy subje cts (all white) were randomly selected from the community register and stratified by sex and age groups in decades from 20 to 79 years of ag e. Persons with a history of hypertension, cerebral apoplexy, diabetes , myocardial or renal disease, and who were taking blood pressure-infl uencing medication were excluded. Ambulatory blood pressure was record ed over 24 h, with measurements taken every 15 min from 07:00 to 22:59 , and every 30 min from 23:00 to 06:59. Systolic blood pressure increa sed only slightly with age and was significantly higher in men than in women. The diastolic blood pressure increased only slightly with age in both sexes until the 50 to 59 years age group and declined thereaft er. The diastolic blood pressure was not different for the two sexes. Both systolic and diastolic blood pressure were approximately 15% lowe r during the night regardless of age or sex. Ambulatory blood pressure during the daytime was on an average of 5 mm Hg lower than office blo od pressure, but the mean difference between the two measurements incr eased with age. The variability of the difference also increased with age. In conclusion: Normal values for ambulatory blood pressure are pr esented in a randomly selected age- and gender-stratified population. Differences between office blood pressure and ambulatory blood pressur e increased with age suggesting that the previously observed higher bl ood pressure seen in the elderly partly might be explained by a greate r impact of white coat hypertension in older people.