title: Population heterogeneity in trajectories of midlife blood pressure.
abstract: BACKGROUND
  We investigated whether there are subgroups with different underlying (latent) trajectories of midlife systolic blood pressure (BP), diastolic BP, and pulse pressure in a UK cohort.
  
  
  METHODS
  Data are from 1840 men and 1819 women with BP measured at ages 36, 43, and 53 years. We used unconditional growth mixture models to test for the presence of latent trajectory classes. Extracted classes were described in terms of a number of known lifetime risk factors, and linked to the risk of undiagnosed angina (Rose questionnaire) at age 53 years.
  
  
  RESULTS
  In both sexes for systolic BP, diastolic BP, and pulse pressure, there was a large "normative" class (>90% of the sample) characterized by gentle annual increases (eg, an increase in male systolic BP of 0.9 mm Hg/year [95% confidence interval = 0.9 to 1.0]), with a smaller class for whom the rate of increase was high (eg, an increase in male systolic BP of 3.1 mm Hg/year [2.8 to 3.4]). In women, there was an additional class for whom BP was high at age 36 and remained high. Persons in the "normative" classes were, on average, heavier at birth and taller at age 7 years, had a lower midlife body mass index, and were less likely to be on antihypertensive medication compared with those in other classes. Among those with no diagnosed cardiovascular disease, those in the classes with more strongly increasing systolic BP and pulse pressure were at greatest risk of angina.
  
  
  CONCLUSIONS
  Our study suggests that in midlife the majority of the population have a gentle underlying increase in BP, but that there also exists an important subgroup in whom BP increases much more markedly. These classes may be useful for identifying those most at risk for cardiovascular disease.
authors.affiliation: MRC Unit for Lifelong Health and Ageing, University College London, London, UK. a.wills@nshd.mrc.ac.uk
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Wills
authors.forename: Debbie A
authors.initials: DA
authors.lastname: Lawlor
authors.forename: Graciela
authors.initials: G
authors.lastname: Muniz-Terrera
authors.forename: Fiona
authors.initials: F
authors.lastname: Matthews
authors.forename: Rachel
authors.initials: R
authors.lastname: Cooper
authors.forename: Arjun K
authors.initials: AK
authors.lastname: Ghosh
authors.forename: Diana
authors.initials: D
authors.lastname: Kuh
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hardy
mesh_terms: D000328:Adult; D000367:Age Factors; D000787:Angina Pectoris / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology*; D002318:Cardiovascular Diseases / Q000503:physiopathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012307:Risk Factors; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology