title: Impact of lower range of prehypertension on cardiovascular events in a general population:  the Hisayama Study.
abstract: OBJECTIVE
  The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC7) defined blood pressure (BP) levels of 120-139/80-89  mmHg as prehypertension. The objective of the present analysis was to examine the impact of prehypertension and its population-attributable fraction for development of cardiovascular events in a general Japanese population.
  
  
  METHODS
  Two thousand, six hundred and thirty-four residents of the town of Hisayama aged at least 40 years without cardiovascular disease were followed up for 19 years. BP categories were defined using JNC7, and prehypertension was divided into the lower (120-129/80-84  mmHg) and higher ranges (130-139/85-89  mmHg). During the follow-up period, 449 participants developed cardiovascular disease (305 strokes and 187 coronary heart diseases).
  
  
  RESULTS
  The frequencies of normal BP, prehypertension, and stages 1 and 2 hypertension were 24.9, 37.7, 23.8, and 13.6%, respectively. The age and sex-adjusted incidence of cardiovascular disease rose progressively with elevation of BP levels (P < 0.001 for trend). The risks of cardiovascular disease in lower and higher ranges of prehypertension were 58% [95% confidence interval (CI) 11-126%] and 70% (95% CI 18-144%) higher than normal BP even after controlling for other cardiovascular risk factors. The population-attributable fraction of prehypertension was 13.2%, which was similar to those of stages 1 and 2 hypertension.
  
  
  CONCLUSIONS
  The risks of cardiovascular disease increased significantly from the lower range of prehypertension in a general Japanese population. Approximately one-third of excess cardiovascular events attributable to elevated BP levels were estimated to occur among individuals with prehypertension.
authors.affiliation: Department of Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Masayo
authors.initials: M
authors.lastname: Fukuhara
authors.forename: Hisatomi
authors.initials: H
authors.lastname: Arima
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Ninomiya
authors.forename: Jun
authors.initials: J
authors.lastname: Hata
authors.forename: Koji
authors.initials: K
authors.lastname: Yonemoto
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Doi
authors.forename: Yoichiro
authors.initials: Y
authors.lastname: Hirakawa
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Matsumura
authors.forename: Takanari
authors.initials: T
authors.lastname: Kitazono
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kiyohara
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D001795:Blood Pressure Determination; D002309:Cardiology / Q000379:methods; D002318:Cardiovascular Diseases / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D003327:Coronary Disease / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D058246:Prehypertension / Q000150:complications* / Q000453:epidemiology*; D011446:Prospective Studies; D012307:Risk Factors; D020521:Stroke / Q000175:diagnosis