Aims: The aims of this prospective observational study are to determine the relationship of sociodemographic factors, psychological factors and several factors measured in blood, with the risk of coronary heart disease (CHD) in a New Zealand population.
Methods: Participants were recruited from two sources: employees of the Fletcher Challenge Group and individuals listed on the general electoral roll for the Auckland region. Baseline and follow up risk factor data were obtained from a questionnaire, blood samples and a simple physical examination. Outcome data on deaths and hospitalisations due to coronary heart disease will be obtained primarily through linkage of participant identifiers to data collected nationally by the New Zealand Health Information Service.
Results: A total of 10,529 individuals agreed to participate (8011 from Fletcher Challenge and 2518 from the electoral roll), representing a response rate of 74%. Within the study population, there was a broad distribution of sociodemographic characteristics including ethnicity-10% of participants were Maori and 5% were of Pacific Islands origin. There was also wide heterogeneity of coronary heart disease risk as judged from the distributions of established risk factors at baseline-5% of participants had evidence of existing coronary heart disease, a quarter were current smokers, a sixth were nondrinkers, almost a half were overweight, a fifth had blood pressure > or = 150/95 mmHg or were receiving antihypertensive treatment and a sixth had cholesterol levels > or = 6.5 mmol/L.
Conclusions: This is the first, large scale prospective observational study of the determinants of coronary heart disease in a New Zealand population. The study participants represent a broad cross section of society, with wide variation in sociodemographic characteristics and coronary heart disease risk. Initial results concerning the relationships of primary interest should be available within 5 years when sufficient coronary heart disease events have been documented to allow reliable analyses.