BACKGROUND:Cardiovascular disease has the highest mortality rate than any other disease globally. Some major risk factors seem to be established in the early stages of life, suggesting preventive strategies as a major means to reduce cardiovascular mortality. The aim of the present study was to investigate the role of socioeconomic status and family characteristics on children's knowledge and perceptions concerning cardiovascular disease risk factors. METHODS:A cross-sectional survey was conducted among 1,728 children (46% male) aged 10-12 years, attending Greek primary schools in Athens; Heraklion (capital city of the island of Crete); Kalamata; Pyrgos; and Sparti (Peloponnese peninsula), Greece. Sampling was conducted on school premises, during the school years 2014-15 and 2015-16 (participation rate, 95-100%). Data were collected via self-administered, anonymous questionnaire. Children's knowledge of various issues related to cardiovascular risk, such as nutrition, physical activity and smoking was also examined. Data on family characteristics were collected through another questionnaire completed by parents. RESULTS:Paternal education level and living with both parents instead of single-parent upbringing, were positively associated with children's knowledge of cardiovascular risk factors (b = 0.42; 95%CI: 0.01-0.83; P = 0.04; and b = 0.78; 95%CI: 0.013-1.43; P = 0.02 respectively). Moreover, children with more siblings seemed to have less sufficient knowledge compared with peers with fewer siblings (b per 1 sibling = -0.24; 95%CI: -0.47 to -0.014; P = 0.04). CONCLUSIONS:The present findings enhance the link between the micro-environment and children's knowledge and perceptions concerning cardiovascular health, providing information to health-care professionals while counseling youths.