7-Year Stability of Blood Pressure in the Canadian Population

Background. The purpose of the study was to examine the 7-year stability of systolic (SBP) and diastolic (DBP) blood pressures in the Canadian population. Methods. The sample included 1,503 participants 7–69 years of age from the 1981 Canada Fitness Survey who were remeasured in Campbell's Survey of 1988. Both SBP and DBP were adjusted for the effects of body mass index (BMI) using regression procedures. Results. Interage correlations from baseline to follow-up ranged from −0.17 to 0.61 for SBP and from −0.22 to 0.51 for DBP. With few exceptions, correlations were positive and significant, and were highest and most consistent in adulthood. Further, between 27 and 39% of participants in the upper or lower quintiles in 1981 remained there in 1988. There were few differences in adiposity between those who remained in the upper or lower quintiles and those who did not. One exception was that males who remained in the upper quintile of SBP had greater values for BMI, sum of skinfolds, and waist circumference at baseline. Among adults, the best predictor of future blood pressure was baseline blood pressure, which accounted for between 12 and 34% of the variance in follow-up blood pressure, followed by age, follow-up BMI, and, in females, baseline physical activity levels. Conclusions. Blood pressure demonstrated low to moderate stability over 7 years in Canada, and baseline level of adiposity was related to the stability of SBP in males.