BACKGROUND: In recent decades various lifestyle factors have been associated with the increasing risk of coronary heart disease. The aim of this study is to assess coronary risk, based on established and emerging lifestyle risk factors such as smoking habit, physical activity, alcohol consumption and depression in a Mediterranean population. METHODS: During 2000--2001, 535 male and 126 female patients with a first event of an acute coronary syndrome and 661 controls matched by sex, age and region were entered into the study. Conditional logistic regression analysis estimated the relative risks of developing coronary heart disease under several scenarios. RESULTS: The multivariate analysis showed that stopping smoking is exponentially related to the reduction of coronary risk. By contrast, passive smoking increases the risk from 48% to 112%. Familial smoking habits are related to current smoking status, increasing the coronary risk fourfold. The effect of depression on coronary risk differs according to gender (+15% in males vs. 32% in females), and interacts with retirement, current smoking, physical inactivity, alcohol consumption and social status, increasing the risk from 15% to 189%. A J-shape association was found between alcohol intake and coronary risk Physical inactivity doubles the coronary risk, while long-term physical activity plays a preventive role in the reduction of coronary risk, even in the elderly. CONCLUSION: Analysis of the data showed that the cluster of established and emerging lifestyle factors poses its particular role for further investigation in the aetiology of coronary heart disease.