Insulin-like growth factor-I as a risk factor for breast cancer among Ugandan women in Mulago National Referral Hospital

Abstract

Background: In Uganda breast cancer is the third commonest cancer in women after cancer of the cervix and Kaposi's sarcoma. The incidence of breast cancer in Uganda has nearly tripled from 11:100,000 in 1961 to 31:100,000 in 2006 and now 36:100,000 in 2010. It’s been considered a neglected disease but the reasons to why there is an increase in the incidence of the disease have not been fully explained. Earlier data supports the hypothesis that there is a relationship between high circulating IGF-I levels and breast cancer risk in some localities. Objective: This study aimed to establish whether high circulating IGF-I is associated with breast cancer amongst Ugandan women. Methods: A case control study, which was conducted in a six month period. Females with histological confirmation of breast cancer recruited as cases while controls were assessed clinically. Data was analyzed using stata 11 using chi-square and linear logistic regression model, P- value reported, and a significance level of 0.05 used. Results: 71cases of cancer breast and 64 controls were recruited. There was significant difference between their mean circulating IGF-I levels (p value0.005). The association was stronger when stratified for menopausal status and the growth factor was strongly associated with premenopausal onset of cancer breast (p value 0.0016) unlike postmenopausal cancer breast (p-value 0.959). Conclusion: The results show that there is a strong association between high levels of circulating IGF-I and cancer breast especially in premenopausal onset of the disease and may be an explanation for the observed low peak age for the disease seen in Uganda.