Knowledge of cardiovascular disease risk factors and the risk of death in middle-aged residents of Krakow

Background: Providing knowledge of cardiovascular disease (CVD) risk factors is the main component of prevention programmes, which aim to reduce the exposure to these factors and decrease CVD incidence and mortality. However, evidence linking knowledge of CVD risk factors and the risk of death is scarce. Aim: The aim of the study was to assess the relation between knowledge of CVD risk factors and the risk of death from all causes in middle-aged residents of Krakow and to assess whether this relation depends on the level of education. Methods: The study sample included 1756 men and 1788 women selected from a population of Krakow residents at age 45-64 years. Knowledge of CVD risk factors was assessed for every risk factor separately using a standard questionnaire. Results were summarised by calculating the "knowledge index" (from -15 to 15 points). Information on deaths was obtained from the registry of Krakow residents. Cox proportional hazards model was used to assess the relation between knowledge of CVD risk factors and all-cause mortality. Results: At baseline examination the participation rate was 66% in men and 65% in women. The proportion of participants with secondary or higher education was 61% in men and 66% in women. Distribution of knowledge index was right skewed, and the median was 11 (interquartile range: 9-13) in both sexes. Median time of follow-up was 14.35 years (interquartile range: 14.30-14.39). There were 307 deaths in men and in women. Men with a low level of knowledge of risk factors had a higher risk of death. However, adjustment for education attenuated the association. After stratification by the level of education, in men with secondary education or higher, an inverse relation between the knowledge of CVD risk factors and the risk of death was found. In this group, men with a low level of knowledge of CVD risk factors had about a 60% higher risk of death, compared to men with high knowledge. In men with low education and in women the risk of death was not associated with knowledge of risk factors. Conclusions: In a Krakow population characterised by a high proportion of residents with secondary or higher education, the association between knowledge of CVD risk factors and the risk of death depended on sex and the level of education. A lower level of knowledge of risk factors was associated with a higher risk of death only in men with secondary or higher education.