The 45 and Up Study has fulfilled a vital role in public health research and practice in Australia, providing locally relevant data to enable research on health issues of importance, including health inequity, this study suggests.

It draws on two case studies to describe attributes of the long-running Study that are key to its success: research on socioeconomic inequalities in cardiovascular disease; and the harms of smoking.

Four key attributes have enabled the success of the Study: its establishment as a collaborative resource, including early and ongoing engagement with researchers and policy and practice partners; its large scale, which makes it ideally suited to quantify associations between risk factors and health outcomes, including for high priority populations; high quality self-reported survey data; and linkage to routinely collected administrative data, including specialised data.

Novel Australian findings on cardiovascular disease (CVD) and smoking illustrate how the Study has contributed to national and international evidence, informing policy and practice. Results on CVD demonstrated individual-level education-related inequalities in CVD incidence and mortality, and greater use of pharmacotherapy for secondary prevention of CVD, in people with low versus high socioeconomic status. In terms of smoking, Study data showed that current smokers have around three times the mortality of never-smokers; that even 'light' smoking of <14 cigarettes per day doubles mortality; that quitting is beneficial at any age; that smoking increases the risk of multiple cancer types; and that smoking causes half of deaths in Aboriginal and Torres Strait Islander adults aged 45 years and over and more than one-third of all deaths in the population. This evidence has been used by more than 50 government and non-government organisations, including contributing to legislation, policy and national and international monitoring and reporting.