Hadjisavvas et al. BMC Cancer 2010, 10:447 http://www.biomedcentral.com/1471-2407/10/447 R E S E A R C H A R T I C L E Open Access An investigation of breast cancer risk factors in Cyprus: a case control study Andreas Hadjisavvas1†, Maria A Loizidou1†, Nicos Middleton2, Thalia Michael1, Rena Papachristoforou1, Eleni Kakouri3, Maria Daniel3, Panayiotis Papadopoulos3, Simon Malas4, Yiola Marcou3, Kyriacos Kyriacou1* Abstract Background: Breast cancer is the most common form of malignancy affecting women worldwide. It is also the leading cancer in females in Cyprus, with approximately 400 new cases diagnosed annually. It is well recognized that genetic variation as well as environmental factors modulate breast cancer risk. The main aim of this study was to assess the strength of associations between recognized risk factors and breast cancer among Cypriot women. This is the first epidemiological investigation on risk factors of breast cancer among the Cypriot female population. Methods: We carried out a case-control study, involving 1,109 breast cancer patients and a group of 1,177 controls who were recruited while participating in the National screening programme for breast cancer. Information on demographic characteristics and potential risk factors were collected from both groups during a standardized interview. Logistic regression analysis was used to assess the strength of the association between each risk factor and breast cancer risk, before and after adjusting for the possible confounding effect of other factors. Results: In multivariable models, family history of breast cancer (OR 1.64, 95% CI 1.23, 2.19) was the strongest predictor of breast cancer risk in the Cypriot population. Late menarche (OR 0.64, 95% CI 0.45, 0.92 among women reaching menarche after the age of 15 vs. before the age of 12) and breastfeeding (OR 0.74, 95% CI 0.59, 0.92) exhibited a strong protective effect. In the case of breastfeeding, the observed effect appeared stronger than the effect of pregnancy alone. Surprisingly, we also observed an inverse association between hormone replacement therapy (HRT) although this may be a product of the retrospective nature of this study. Conclusion: Overall the findings of our study corroborate with the results of previous investigations on descriptive epidemiology of risk factors for breast cancer. This investigation provides important background information for designing detailed studies that aim to improve our understanding of the epidemiology of breast cancer in the Cypriot population, including the study of gene-environment interactions. Furthermore, our study provides the first scientific evidence for formulating targeted campaigns for prevention and early diagnosis of breast cancer in Cyprus. Background Breast cancer is the most frequent malignancy in the female population of Europe and North America where an estimated 1 in 9 women are at risk of developing the disease [1]. Numerous epidemiological studies over the last three decades have revealed a number of risk factors associated with breast cancer [2-4]. In addition to genetic and reproductive factors, breast cancer risk * Correspondence: kyriacos@cing.ac.cy † Contributed equally 1Department of EM/Molecular Pathology, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus Full list of author information is available at the end of the article displays wide ethnic and geographic variation [5]. Within Europe the incidence varies by almost two-fold. It is highest in Northern European countries, with an estimated 84.6 cases per 100,000 population with inter- mediate rates recorded in Southern Europe and lowest rates occurring in Eastern Europe with 42.6 cases per 100,000 population [6]. In addition to the geographic variation, influences on incidence rates, have also been attributed to differences in the use of mammography, diet, physical activity, body size, alcohol consumption and socioeconomic and reproductive factors [7]. The discovery of highly penetrant breast cancer susceptibility genes such as the BRCA genes in the mid 1990’s [8,9] © 2010 Hadjisavvas et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.