Global Assessment of the Relationship Between Breast Cancer Risk and Dietary Intake: An Ecological Study

Purpose Breast cancer (BC) is a leading cause of morbidity and mortality worldwide, with its incidence varying significantly across different regions. While individual-level studies have explored the link between diet and BC risk, a comprehensive global assessment using an ecological approach is lacking. The aim of this study is to describe and evaluate the relationship between BC incidence and food and nutrient intake on a global scale. Design An ecological study using publicly available country-level data from global sources. Setting Country-level data were obtained from the Global Cancer Observatory and the Global Dietary Database. Sample The present study included data of 175 countries, covering a wide range of geographical areas and different food cultures. Measures Key measures included country-level data on women’s intake of various food and nutrients, alongside age-standardized BC incidence rates. Additional country-level covariates were also considered to account for potential confounding. Analyses For initial exploratory assessment, comparisons of median food and nutrient intake were done using the Mann-Whitney U test. Additionally, multiple linear regression was applied to assess the associations between BC incidence and various food and nutrient intake variables, adjusting for potential confounding factors. Results The multivariate analysis, after rigorous adjustment for confounding factors, initially revealed several food and nutrients that appeared to be significantly associated with BC risk. However, after applying the Bonferroni correction, these associations were no longer statistically significant, with the exception of alcohol consumption, which remained positively associated with BC incidence (β = 0.209, P = 0.048). Conclusion This study suggests that alcohol consumption may be a potential risk factor for BC and highlight the complexity of the relationship between dietary factors and BC risk. The findings of this study could serve as a baseline for future in-depth individual-level research that aims to assess such a relationship.