Cardiovascular disease (CVD) is the leading cause of death among New Zealanders. There is increasing evidence that low body levels of vitamin D may increase the risk of cardiovascular disease. In New Zealand Maori, Pacific and South Asian people and older adult Europeans have low vitamin D levels, particularly in winter and higher rates of CVD. We aim to carry out a case cohort study to determine whether low serum vitamin D levels predict CVD events in 750 cases and 750 controls and if so whether this is mediated by inflammatory markers. In addition, we propose determining whether low vitamin D levels are associated with non-cardiovascular disease mortality in 300 cases and 300 controls. If these hypotheses are true, the study has the potential to lead new public health strategies for preventing cardiovascular diseases, either by vitamin D supplementation or safe sun exposure.