Association between obesity biomarkers and breast cancer risk in Nigeria.

Abstract

e12556 Background: Obesity is an important risk factor for breast cancer, but current strategies have not addressed it for primary prevention of breast cancer. To provide evidence for this need, we aimed to determine the prevalence of overweight and obesity, serum levels of certain obesity biomarkers and association between those biomarkers and breast cancer risk. Methods: This was a case-control study at Oncology clinic, University of Nigeria Teaching Hospital, Enugu. Adult females diagnosed with breast cancer were recruited as cases, while adult females who were free of any type of cancer were the controls. Questionnaires were used to collect data, anthropometry measurements taken and venous blood obtained for determination of biomarkers (serum insulin, IGF-1, estradiol and leptin) concentrations. The serum were analyzed using ELISA methods. Statistical analysis was done with SPSS, and p-value < 0.05 was considered as statistically significant. Results: Forty cases and 40 controls were included in the study with mean±sd age of 49±10.4years and 47±13.8years respectively, p > 0.05. There was no difference in the body mass index (BMI) (27±6.6 vs 26±5.0 kg/m2), waist circumference (89±12.4 vs 89±11.8 cm), and waist-to-hip ratio (0.91±0.04 vs 0.91±0.06 between the cases and controls (p > 0.05). Prevalence of overweight and obesity among the cases using BMI was 57.5% (23/40). Their serum biomarkers had median (interquartile range) of Estradiol 50.6 (43.4 – 75.7)pmol/L, Leptin 7.0 (2.1-16.5)ng/ml, IGF-1 4.3 (2.2-9.3)nmol/L and insulin 23.8(8.4-55.0)pmol/L; which were statistically different from the controls p < 0.05, but not insulin. Significant associations with breast cancer risk were Estradiol OR 0.996 (95%CI 0.993-0.999) p = 0.023*, and Leptin OR 0.905 (95%CI 0.826-0.991) p = 0.032*. Conclusions: Estradiol and Leptin- a hormone predominantly made by adipose cells, showed significant associations with breast cancer risk. Since the mechanism of estradiol in breast cancer pathogenesis has already been well described, there is need to elucidate the complex molecular network of leptin signaling responsible for breast cancer which may provide novel ideas for prevention and therapeutic target. Association of obesity biomarkers with breast cancer risk. Obesity Parameters B S.E. Wald df Sig. Exp(B) 95.0% C.I.for EXP(B)Lower 95.0% C.I.for EXP(B)Upper BMI (kg/m 2 ) .882 1.211 Waist circumference (cm) -.008 .042 .038 1 .846 .992 .914 1.077 Waist to hip ratio 9.521 7.152 1.772 1 .183 1.364E4 .011 1.668E10 Insulin (pmol/L) .014 .010 1.967 1 .161 1.014 .994 1.034 IGF1 (nmolL) -.054 .066 .664 1 .415 .948 .833 1.078 E2 (pmolL) -.004 .002 5.192 1 .023* .996 .993 .999 Leptin (ng/mL) -.100 .046 4.602 1 .032* .905 .826 .991 Constant -6.662 6.177 1.163 1 .281 .001