Objective: To classify causes of death in New Zealand by risk factor (in addition to condition) as a planning tool for health promotion.
Method: Deaths occurring in New Zealand in 1997 were classified by 20 prevalent risk factors using a combination of categorical attribution (rule-based) and counterfactual modelling (population-attributable risk-based) approaches.
Results: Approximately 30% of deaths were attributed to the joint effect of dietary factors. Tobacco consumption was responsible for 18% of deaths and insufficient physical activity for almost 10%. Less important behavioural risk factors included alcohol consumption (3%), illicit drug use (0.5%) and unsafe sex (0.5%). Among biological risk factors, higher than optimal total blood cholesterol, systolic blood pressure and body mass index accounted for 17%, 15% and 12% of deaths respectively. Deprivation contributed to 17% of deaths, and adverse in-hospital events to 6%. Among environmental exposures, microbes accounted for 6.5% of deaths, air pollution 3.5% and occupational diseases and injuries 0.5%. Among injury hazards, risk factors related to road traffic were responsible for 2% of deaths, while violence accounted for 2.5% of deaths, mostly through suicide. Cross-classifying deaths by both condition and risk factor, 90% of ischaemic heart disease and 80% of stroke, but only 30% of cancer deaths, could be attributed to specific risk factors.
Conclusions: This is the first comprehensive ranking of causes of death at the level of risk factors available for New Zealand and should prove useful as a planning tool, especially for disease prevention and health promotion.