Risk factors for endometrial cancer among black South African women: a case control study
Date
2010-04-13T11:32:34Z
Authors
Ali, Aus Tariq
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Abstract
Introduction: Endometrial cancer is a gynaecological cancer that mostly affects women
in their sixth and seventh decades of life. It is the fourth most common malignancy in
women and ranks eighth among all causes of female cancer in terms of age-adjusted
mortality. In developed and numerous developing countries endometrial cancer, as well
as other types of cancer in women, is an ever-increasing threat that may be explained,
among other reasons, by increased life expectancy and a reduction in fertility or birth
rates. Conversely, in South Africa and most other African countries, the previous
reasons do not exist, because there is a decline in life expectancy due to increased HIV,
low income, and a high fertility rate. International epidemiological studies have
established significant relationships between endometrial cancer and risk factors such
as the woman’s age, race, early menarche and late menopause, parity, a history of
breast or ovarian cancer, the use of endogenous estrogens, concomitant diabetes,
family history of breast and ovarian cancer, estrogen therapy, obesity, and the use of
tamoxifen. The aim of the study was to identify risk factors associated with endometrial
cancer among black South African women.
Method: The present case control study comprised black South African women
diagnosed with a cancer in Johannesburg, between 1995 and 2005. The study included
592 women aged 27 to 90 years who were admitted to three main public hospitals in the
city of Johannesburg with histologically confirmed cancers. 148 cases with endometrial
cancer and 444 women with other forms of cancer were analysed. Only newly occurring
cases (incident) were included. Women in the control group consisted of those with
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cancers not associated with reproductive or hormonal factors, i.e. not cancers of the
breast or the female reproductive system. Data handling, cleaning and analysis were
done using Stata 9 (STATA).
Results: Univariate analysis showed that the risk for endometrial cancer was
significantly (P<0.05) affected by: miscarriages, the place of former residence, place of
current residence, the use of snuff, wine consumption, age of the youngest child,
diabetes, age of menarche, age of menopause, and menstrual status. Smoking was
found to be a protective factor for endometrial cancer compared to other cancers. After
multivariate adjustment, endometrial cancer risk was significantly (P<0, 05) associated
with miscarriages, age at menarche, and earlier completion of childbearing. Smoking
remained a protective factor against endometrial cancer.
Conclusion: The current study reports similar results to those observed in other
international investigations. The risk of endometrial cancer was higher among women
who were older, women who experienced miscarriages, and those who fell pregnant
early in their reproductive lives. Smoking was a protective factor against endometrial
cancer compared to other cancers. However, comparing the cases of endometrial
cancer with smoking-associated cancer controls (i.e. lung cancer, oesophageal cancer,
and mouth cancer) might have distorted the results. A more appropriate control group
for confirming the relationship between smoking and endometrial cancer would be
subjects with no cancer. Also, it will be important to evaluate the risk factors for cancer
among the other race groups in South Africa.
Description
MSc (Med), Biostatistics and Epidemiology, Faculty of Health Sciences, University of the Witwatersrand, 2009
Keywords
endometrial cancer, risk factors, black women