The Relationship between Breast Cancer and the Most Common Non-contagious Disease Risk Factors: an Ecologic Study

Breast cancer is the most common cause of cancer-related deaths among women worldwide. Each year it is newly diagnosed in more than 1.1 million women around the world. The aims of this study were to investigate the role of dietary factors such as consumption of vegetables, fruits, dairy products, fried food, fish, and salt along with food, and factors such as weight, physical activity, hypertension, diabetes, smoking, educational level, and marital status in the development of colorectal cancer. First we calculated the bilateral Pierson correlation coefficient between the mean incidences of breast cancer during 2001-2006, and the proportion of risk factors of non-contagious diseases. Then the risk factors with statistically significant correlation coefficient were separated and were entered into the multiple linear regressions model, in order to investigate the effects of that factor both individually and in relation to other factors over these years. Based on the Pearson correlation results, there was a significant positive correlation between breast cancer in women, and the percentage of diabetic women, fish consumptions per week, academic education, and lack of consumption of fruits per week. However, there was a significant negative correlation between the incidence of breast cancer, and lack of fish consumption per week, percentage of illiteracy, and consumption of fruit per week. However, in regression analysis there was a significant correlation between university education, fruit consumption per week, and the percentage of diabetic women. Since this was an ecological study we should be careful of ecological fallacy in the interpretation of results. This study can only hypothesize about some possible factors causing breast cancer; therefore, other studies are required, these could be cohort or case control studies.