Trends in coronary heart disease risk factors in Auckland 1982-94

Abstract

Aims: This paper describes trends in major coronary heart disease risk factors over the period 1982 to 1994 in the city of Auckland, New Zealand.

Methods: Coronary heart disease risk factor levels were measured in three cross-sectional surveys in Auckland in 1982, 1986-8 and 1993-4, following a standardised protocol. Random samples of nonMaori, nonPacific Island adults aged 35-64 years were selected from the Auckland general electoral rolls using similar methods in all three surveys. Participants attended a study centre for interview and risk factor measurement.

Results: The analyses presented are based on samples of 1029 men and 569 women in 1982, 541 men and 365 women in 1986-8, and 712 men and 685 women in 1993-4. The data are directly age-standardised to the 1986 New Zealand population. Over the 12 year period the prevalence of self-reported cigarette consumption declined significantly from 28.6% to 16.9% in men and from 24.5% to 14.8% in women. Mean serum total cholesterol showed little change between 1982 and 1986-8 but declined significantly between 1986-8 and 1993-4 by approximately 6% from 6.12 mmol/L to 5.73 mmol/L in men and by 9% from 6.17 mmol/L to 5.60 mmol/L in women. Mean serum high density lipoprotein (HDL) cholesterol showed a modest increase between 1982 and 1986-8 but declined significantly between 1986-8 and 1993-4 by 12% from 1.25 mmol/L to 1.10 mmol/L in men and by 9% from 1.55 mmol/L in women to 1.40 mmol/L in women. The total cholesterol to HDL cholesterol ratio increased significantly between 1986-8 and 1993-4 by 6% in men but showed little change in women. Mean blood pressure levels fell by 4-6 mmHg systolic and 6-7 mmHg diastolic over the 12 year period in men and women. Mean body mass index increased significantly from 25.6 to 26.4 in men and from 24.5 to 25.1 in women during this period.

Conclusions: Over the 12 year period, 1982-94 there have been substantial reductions in the prevalence of self reported cigarette smoking, mean serum total cholesterol levels and mean blood pressure levels in middle aged Aucklanders. Of concern, the prevalence of obesity has increased and mean serum HDL cholesterol levels have fallen over the period. Coronary heart disease prevention and control programmes appear to have been successful in reducing the prevalence of most major coronary heart disease risk factors however some reorientation will be required to redress the adverse trends in HDL cholesterol levels and obesity.