Association between Anthropometric Indices and Breast Cancer Based on the Data of the Enrolment Phase (cross-sectional) in Tabari Cohort Study: The Causal Relationship or Violation of Temporality

Background and purpose: The relationship between obesity and the risk of breast cancer has been highlighted in some studies. This research aimed at studying the association between anthropometric indices and breast cancer based on enrolment phase (cross-sectional phase) data in Tabari cohort study. Materials and methods: In this cohort, 51 cases of breast cancer were recorded which were considered as the case group. Also, 153 individuals (without any type of cancer) from Tabari cohort population were randomly selected as control group. Data analysis was performed applying independent t-test, chi-square, and multivariate logistic regression. Results: The frequency of waist circumference ≥88 cm in case group was slightly lower than that of the control group (74.5% vs. 75.2%, P= 0.926). In case group, the frequency of waist to hip ratio (less than 0.85) was lower than that of the control group (70.6% vs. 80.4%, P= 0.144). The risk of breast cancer was found to be higher in rural population (OR: 8.28, P<0.001) and in women with higher education (OR: 0.06, P<0.001). Conclusion: This study did not confirm the association between anthropometric indices and breast cancer.