Reducing obesity is an important preventive measure for postmenopausal breast cancer, but the association between adiposity and breast cancer risk at premenopausal ages is less clear. So far, studies on body fatness and breast cancer risk have been undertaken mainly in Caucasian women, and there are indications that breast cancer may be different in women of African ethnicity. Therefore, the influences of diet, body fatness, and physical activity on this disease need to be investigated directly in African women in Africa. South Africa, the richest country in sub-Saharan Africa, represents an ideal setting for this research, because of the uniqueness of this population, which is undergoing a lifestyle transition and has particular co-morbidities, i.e. a high prevalence of HIV, that may offer special insights into breast cancer, the most common incident cancer in women. In South Africa, the prevalence of overweight and obesity is high (61% in urban women and 48% in rural women), and body composition (percentage of lean tissue vs fat) may have different distributions in black and white women and thus have different associations with breast cancer risk.
The South Africa Breast Cancer (SABC) study is a population-based case—control study set up at the Chris Hani Baragwanath Hospital, in Soweto, South Africa, to study the etiology of breast cancer in black South African women. Women recruited to the study are asked to complete questionnaires on lifestyle, diet, and environmental factors, and to provide blood and urine specimens that will be used for research purposes. Tumour samples will also be collected, to identify molecular breast cancer subtypes by immunohistochemical analyses. Different types of adiposity will be measured using dual-energy X-ray absorptiometry (DXA).
The study is very important, because it is among the first to study specific factors in the black South African population that may be associated with specific subtypes of breast cancer as well as with specific lifestyle and dietary habits. The availability of a large biobank with blood and urine samples, the comprehensive database of responses to standardized lifestyle and dietary questionnaires, and refined measurements of adiposity from hundreds of women will be of great value for breast cancer research in this population over the next decades.
The project is supported by the World Cancer Research Fund International, United Kingdom.