Relationship between body mass index and stage at breast cancer diagnosis

Background: The relationship between Body Mass Index (BMI) and risk of developing breast cancer is very well researched. However, there is a relative dearth of studies on the relationship between BMI and the stage of breast cancer at diagnosis. This study aims to explore this relationship. 

Aims/objectives: The aim of this study was to evaluate if there is any relationship between BMI and the stage of breast cancer at diagnosis among women attending the Breast Clinic of a tertiary health facility in Nigeria.                       

Methods: This was a retrospective study (n=110) conducted at Nnamdi Azikiwe University Teaching Hospital, Anambra State. The BMI categories of participants  and the clinicopathological stages of their tumours were obtained from the medical files of consenting patients who met the inclusion criteria. The data was analysed using the  Statistical Programme for the Social Sciences (SPSS) Version 20.0. Logistic regression was used to draw association between stages of cancer at diagnosis and BMI categories. 

Results: The mean BMI(SD) was  28.09(6.35)kg/m2. There was a moderate, statistically significant positive correlation between being overweight/obese and having a late stage at diagnosis of breast cancer (OR=2.36, 95% C.I.: 1.06-5.27; P=0.03). After controlling for age, occupation and highest educational attainment, this association was slightly stronger (O.R=3.29, 95% C.I: 1.31-9.10). 

Conclusion: There is a need to place particular emphasis on very rigorous breast self-examination in women with high BMI as they are likely to present with more advanced tumours.