Several mechanisms have been proposed to explain the adverse effect of obesity on quality of life among postmenopausal breast cancer survivors (BCS) using aromatase inhibitors. Although a number of inflammatory markers are associated with different cancer metastasis in many studies, no study has yet been conducted to establish the association between high sensitivity C-reactive protein (hs-CRP) and anthropometric markers (e.g. BMI, waist circumference) among postmenopausal BCS in the South African population. This study was performed to determine the status of serum levels of CRP in obese, overweight and normal weight postmenopausal BCS, in order to determine the relationship between inflammatory marker levels and obesity after an extended 24-month follow-up at Tygreberg Hospital.
A prospective cohort of postmenopausal BCS voluntarily accepted to participate in the study. A standardized BC questionnaire regarding personal health, tumor subtypes, comorbidities, treatment options, BMI, and waist circumference was administered to the participants and serum CRP level were measured. Patients were stratified based on the BMI status, waist circumference and CRP level. Data were managed and analyzed, using STATA version 14. A linear regression model was performed to estimate the relationship between CRP level and BMI. An extended-model approach was used for covariate adjustment.
A total of 121 participants were considered for analysis. Mean age of 61 years (SD= 7,11; 95%CI: 60-62). Descriptive analysis showed that 101(83.47%) were mixed ancestry, 15(12.40%) Caucasian, 4(2.48%) Indian and 2(1. 65%) Black. Regarding BMI stratification, 71(56.35%) women were obese, 28(22, 22%) had a normal weight, 23(18.25%) were overweight, and 4(3.17%) were underweight. Linear regression revealed that hs-CRP was associated with waist circumference (OR: 7.5; p= 0. 0116; 95%CI: 1.45 to 39.61), and BMI (OR: 2.15; p=0.034, 95%CI: 1.02 to 4.56). Waist circumference was associated with hypertension (OR: 3, 83; p= 0.003, 95%CI: 1.56 to 9.39), and chemotherapy reduced waist circumference by 0.29(p= 0. 016; 95%CI: 0.11 to 0. 79). Other factors were not associated with CRP or BMI.
High BMI and large waist circumference are independently associated with higher levels of CRP among postmenopausal BCS survivors taking aromatase inhibitors. Further studies should be performed to establish the association between bone mineral density and homocysteine, as well as, other genetic risk factors such as Ki 67.
Key words: Postmenopausal breast cancer, Obesity, High-sensitivity C-reactive protein, waist circumference