Link to the University of Pittsburgh Homepage
Link to the University Library System Homepage Link to the Contact Us Form


Okobia, Michael Nkwor (2005) ESTROGENS, GENETIC POLYMORPHISMS AND BREAST CANCER RISK IN NIGERIAN WOMEN. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

Primary Text

Download (1MB) | Preview


Breast cancer is major cause of morbidity and mortality globally and the incidence appears to be rising faster in population groups that hitherto experience lower incidence. This case control study recruiting 250 women with breast cancer and 250 age-matched controls from four University Teaching Hospitals in Nigeria was designed to evaluate the risk factors for breast cancer in Nigerian women. Family history of breast cancer was associated with a 15-fold increased risk of breast cancer [Odd ratio (OR) = 14.99, 95% Confidence interval (CI), 1.98, 113.47]. Also, waist to hip ratio (OR = 2.10, 95% CI 1.44, 3.06), history of abortion (OR = 2.83, 95% CI 1.12, 7.19), increasing age at first childbirth (OR = 1.39 95% CI 1.11, 1.73) and higher level of education (OR = 1.31, 95% CI 1.07, 1.61) conferred increased risk of breast cancer. Increasing parity (OR = 0.87, 95% CI 0.77, 0.99) and increasing duration of breastfeeding (OR = 0.75, 95% CI 0.62, 0.91) conferred protection against breast cancer. In the final multivariate conditional logistic regression in all women, carrying at least one low-activity COMT (Met) allele was associated with a significant 43% reduced risk of breast cancer (OR = 0.57, 95% CI 0.36-0.91). While harboring the CYP1A1 M1 polymorphic variant was associated with non-significant reduced risk of breast cancer (OR = 0.79, 95% CI 0.48-1.29), the CYP1A1 M3 polymorphism conferred a non-significant 24% reduced risk of breast cancer (OR = 0.76, 95% CI 0.47-1.22). Results of this study have important public health implications; it has provided evidence for a role for reproductive and other variables in susceptibility to breast cancer in indigenous African women, thus contributing to the global epidemiologic literature on risk factors for breast cancer in populations of African ancestry. It has also provided data suggesting protection for breast cancer for women harboring the low-activity COMT (Met) allele of the codon 158 polymorphism of the COMT gene. In addition, the findings of this study will serve a useful resource tool in future research and policy decisions aimed at breast cancer control and prevention in these populations.


Social Networking:
Share |


Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Okobia, Michael Nkwormnost4@pitt.eduMNOST4
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairBunker, Clareann H
Committee MemberKammerer, Candace M
Committee MemberZmuda, Joseph M
Committee MemberKuller, Lewis H
Committee MemberVogel, Victor G
Date: 9 June 2005
Date Type: Completion
Defense Date: 6 April 2005
Approval Date: 9 June 2005
Submission Date: 14 April 2005
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: School of Public Health > Epidemiology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: breast cancer; Estrogens; Nigeria; risk factors
Other ID:, etd-04142005-135825
Date Deposited: 10 Nov 2011 19:37
Last Modified: 15 Nov 2016 13:40


Monthly Views for the past 3 years

Plum Analytics

Actions (login required)

View Item View Item