Abstract PO5-27-04: The epidemiological profile and lifestyle of non-village indigenous women from Amazonas, Brazil and the likely impact on breast cancer mortality
Authors: Da Silva Maria Riselda Vinhote , Guimarães Lilian Cristina De Souza , Nazário Afonso , Castro Mariana Guimaraes De Oliveira 
Published: May 2024

Introduction: The high and growing incidence of breast cancer is a reality in almost every continent. However, the low mortality from this neoplasm among indigenous people of Amazonas, Brazil, is an intriguing fact (table 1). Inspite having a lower life expectancy at birth, the magnitude of low mortality is even greater. Indigenous women have gradually integrated into the non-indigenous community, and the reality of low mortality from breast cancer may be at risk of not existing in the future if the justification is in their reproductive epidemiological profile and lifestyle. Objective: This work seeks to find variables that can justify the fact that indigenous women from the Amazon region die less from breast cancer when compared to non-indigenous women. To achieve this, we evaluated reproductive epidemiological factors and lifestyle in non-village indigenous women and compared them with the same data in non-indigenous women. Methods: This is a cross-sectional study consisting of a convenience sample in which all indigenous people treated at the Mastology Outpatient Clinic of the Getúlio Vargas University Hospital of the Federal University of Amazonas were invited to participate from September 2020 to March 2023. There were 126 women: 39 non-village indigenous people who have lived in Manaus for more than 5 years and are integrated into society, 47 non-village indigenous people who live in riverside and interior populations of Amazonas - or in Manaus for less than 5 years - and 40 non-indigenous individuals. A questionnaire in interview format was administered with the objective of evaluating epidemiological and reproductive aspects such as age, education, BMI, menarche, parity, age at first pregnancy, breastfeeding, use of hormonal medications as well as lifestyle factors including smoking, alcohol consumption, dietary habits, physical activity, use of herbs, roots and seeds for therapeutic purposes and practice of religious devotional habits. Results: There was no difference in age, BMI, education, menarche and parity between the interviewed patients, nor in the assessment of the consumption of milk, sugar, fruits, vegetables and legumes, smoking habits, alcohol intake or physical activity between the groups. Indigenous women living in Manaus had a lower age at first pregnancy when compared to non-indigenous women. The variable “breastfeeding time” did not reach statistical significance but demonstrated a very close index (p 0.058) and a tendency to suggest that indigenous people, regardless of their place of residence, breastfeed for a longer duration. Non-indigenous women had a longer history of using hormonal medications when compared to indigenous women living in Manaus. Regarding meat consumption habits, indigenous women living in riverside and interior populations showed higher percentages of sporadic consumption of beef, sporadic consumption of wild animals, and daily consumption of white meat compared to non-indigenous people. On the other hand, non-indigenous women had a higher percentage of never having consumed wild animal meat when compared to the two other groups. Among indigenous women from riverside populations, there was a lower percentage of religious practices. The consumption of herbs, roots or seeds for therapeutic purposes was more commonly observed among indigenous people living in Manaus when compared to non-indigenous people. Conclusion: No epidemiological or lifestyle variables were found in both groups of indigenous people that justify the low mortality from breast cancer in these women. However, although the variable “breastfeeding time” did not reach statistical significance, it demonstrated a very close index (p 0.058) and a tendency to suggest that indigenous people, regardless of their place of residence, breastfeed for a longer duration. This could be a potential explanation for the low mortality from this disease among indigenous women.

Table 1: Participation of breast cancer deaths in the total number of deaths in women over 20 years of age in the State of Amazonas Source: prepared by researchers

Table 2 - Menarch, parity (childbirth and miscarage), breastfeed, Family history of breast cancer, image exam

Table 3: Red and white meat consumption

Citation Format: Maria Riselda Vinhote Da Silva, Lilian Cristina De Souza Guimarães, Afonso Nazário, Mariana Guimaraes De Oliveira Castro. The epidemiological profile and lifestyle of non-village indigenous women from Amazonas, Brazil and the likely impact on breast cancer mortality [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-27-04.