Changes in blood pressure among students attending Glasgow University between 1948 and 1968: analyses of cross sectional surveys

Objectives To examine the changes in blood pressure over time in a cohort o f young adults attending university between 1948 and 1968. Design Cross sectional study. Setting Glasgow University. Participants 12 414 students aged 16-25 years-9248 men (mean age 19.9 years ) and 3164 women (19.2 years)-who participated in health screening on enter ing university between 1948 and 1968. Main outcome measures Systolic and diastolic blood pressure. Results in male students mean systolic blood pressure adjusted for age decr eased from 134.5 (95% confidence interval 133.8 to 135.2) mm Hg in those bo rn before 1929 to 125.7 (125.0 to 126.3) mm Hg in those born after 1945, an d diastolic blood pressure dropped from 80.3 (79.8 to 80.8) mm Hg to 74.7 ( 74.2 to 75.1) nlm Hg. For female students the corresponding declines were f rom 129.0 (127.5 to 130.5) mm Hg to 120.6 (119.8 to 121.4) mm Hg and from 7 9.7 78.7 to 80.6) mm Hg to 77.0 (76.5 to 77.5) mm Hg. Adjustment for potent ial confounding factors made little difference to these findings. The propo rtion of students with hypertension declined substantially in both sexes. Conclusions Substantial declines in systolic and diastolic blood pressure o ver time were occurring up to 50 years ago in young adults who were not tak ing antihypertensive medication. Since blood pressure tracks into adult lif e, the results of the cross sectional comparisons suggest that factors acti ng in early life may be important in determining population risk of cardiov ascular disease. Changes in such factors may have made important contributi ons to the decline in rates of cardiovascular diseases, particularly stroke , seen in developed countries during the past century.