Characteristics of a community-based distribution of home blood pressure in Ohasama in northern Japan.
OBJECTIVE
To evaluate the distribution, reference values and day-to-day variation of blood pressure of untreated subjects measured at home.


METHODS
Cross-sectional study of a cohort.


METHODS
General community in northern Japan.


METHODS
Blood pressure was measured in 871 subjects (mean +/- SD age 46.0 +/- 19.5 years, range 7-98, constituting 38.7% of the local population of Uchikawama region, Ohasama) who were not receiving antihypertensive medication.


METHODS
Subjects measured their own blood pressure at home at least three times (mean +/- SD 19.7 +/- 8.4) each morning using a semi-automatic oscillometric blood pressure measuring device. Screening blood pressure was measured once.


METHODS
Distribution of home blood pressure in the study population as a whole and with respect to age and sex, and the distribution of day-to-day variation of home blood pressure were determined.


RESULTS
Mean home blood pressure was 117.3 +/- 13.4/69.3 +/- 9.7 mmHg (95% confidence interval 116.4-118.2/68.7-70.0). The 95th centile value was 143/85 mmHg, mean+SD 131/79 mmHg and mean + 2SD 144/89 mmHg. Mean screening blood pressure was 126.2 +/- 18.9/72.1 +/- 11.7 mmHg (95th centile 159/92 mmHg). Age- and sex-specific 95th centile values as well as mean +/- SD were obtained. Mean+SD, mean + 2SD and the 95th centile values obtained as reference upper limits of home blood pressure from subjects identified as normotensive by screening blood pressure (n = 707) were 125/77, 137/86 and 134/83 mmHg, respectively. Home blood pressure increased gradually with increasing age in both men and women, although blood pressure was significantly higher in men until 50 years of age. Day-to-day variation of home systolic blood pressure also increased with age.


CONCLUSIONS
Since the distribution of home blood pressure values was affected by age and sex, age- and sex-matched reference values for home blood pressure should be established. Home blood pressure values in elderly subjects should be evaluated carefully, since these exhibit greater day-to-day variation.
Imai
Y
Y
Department of Medicine, Tohoku University School of Medicine, Sendai, Japan.
Satoh
H
H
Nagai
K
K
Sakuma
M
M
Sakuma
H
H
Minami
N
N
Munakata
M
M
Hashimoto
J
J
Yamagishi
T
T
Watanabe
N
N
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000554:Ambulatory Care Facilities; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000295:instrumentation / Q000706:statistics & numerical data; D002648:Child; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007564:Japan; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D012016:Reference Values; D012648:Self Care