TRENDS AND DETERMINANTS OF BLOOD-PRESSURE IN AUCKLAND, NEW-ZEALAND 1982-94

Aim. To describe blood pressure trends in Auckland, New Zealand from 1 982 to 1994 and assess possible explanations for the trends. Methods. Three cross sectional surveys of cardiovascular risk factors were unde rtaken in 1982, 1986-8 and 1993-4, with a total of 3806 European men a nd women aged 35-64 years randomly selected from Auckland electoral ro lls. Results. Mean systolic blood pressure fell in males from 132.2 mm Hg in 1982 to 126.3 mmHg in 1993-4, and in females from 125.9 mmHg in 1982 to 121.7 mmHg in 1993-4. Both male and female diastolic mean bloo d pressure decreased more than 6 mmHg over the 12 years. The prevalenc e of antihypertensive drug use fell over the 12 year period. Regressio n analysis revealed a positive association between blood pressure and blood lipids. Body mass index (BMI) was also positively related to blo od pressure while cigarette smoking was inversely related. However, co ncurrent trends in blood lipids, BMI and cigarette smoking could accou nt for less than 6% of the average decline in systolic blood pressure over the 12 year period. Conclusion. There has been a substantial fall in mean blood pressure levels in Auckland adults aged 35-64 years whi ch appears to be due to a shift in the general population blood pressu re. The reduction in blood pressure is not explained by changes in pha rmaceutical interventions and only a small part of the decline can be explained by concurrent trends in cardiovascular risk factors.