20. Rabkin, S.W., Mathewson, F.A.L. Tate, R.B.: Longitudinal blood pressure measurements during a 26-year observation period and the risk of ischemic heart disease. Am J Epid 109 (6): 650-662 1979.

The importance of serial blood pressure (BP) measurements over long periods of time in the prediction of ischemic heart disease has received relatively little attention. In the Manitoba Study cohort of 3983 men, most of them between 25-34 years of age at entry, systolic blood pressure (SBP) measurements at entry and at four other examinations approximately five years apart were related to the subsequent incidence of ischemic heart disease (IHD) during the 25-year observation period, from entry at July 1, 1948 to June 30, 1974. Because both age and SBP may determine the rate of rise in SBP after entry, the data were analyzed using multivariate techniques as well as cross-classification methods. After adjusting for entry age and SBP, change in SBP from entry to the later four examinations showed a greater increase in those over 45 years of age, for longer intervals between measurements and most importantly in those who later developed IHD. In multivariate analysis, SBP after entry was more strongly associated with IHD incidence than entry SBP. SBP closest to the event was the most significant SBP measurement but an earlier SBP measurement, usually five years before the last SBP, was also a significant consideration in IHD predication. Therefore, in the evaluation of SBP for assessment of IHD risk, longitudinal SBP data after entry are an important consideration.

Key words: blood pressure, longitudinal studies, ischemic heart disease.