Stressfull life events and female breast cancer: meta-analysis
Introduction: Several risk factors for breast cancer are well established, however the role of stress as one of these factors requires proof. Objective: Verify the association of life events which produce stress with the primary incidence of breast cancer among women. Method: Systematic review in the data bases MEDLINE/Pubmed, LILACS and Cochrane Library, in the period between 2006 and 2007, with no language restriction. The selection of studies was carried out by three researchers and included the following inclusion criteria: patients over 18 years old, primary observational studies, first occurrence of breast cancer, measurement of stress according to categories, intensity and frequency of events, results expressed as relative risk (RR) with interval of confidence (IC). The methodological quality was evaluated by Downs and Black?s criteria, while the level of evidence was evaluated by Melnyk and Fineout-Oveholt?s classification. For meta-analysis the studies were grouped in three analyses: two analyses owing to the categories widowhood and divorce, and one analysis considering the intensity self perceived and frequency of events. The meta-analysis was carried out by the program Data Analysis and Statistical Software-Stata, version 9.0. with application of the test Q to estimate heterogeneity and random effects model to calculate the combined effect. Analyses of sensibility and bias were not carried out due to the small number of studies. Result: Eight students were included in an initial sample of 621 articles. The meta-analysis consisted of six case-control studies and two of cohort. The scores of methodological quality varied between 14 and 20 (average=17), all of them with evidence level IV. No association was found for stressing events, widowhood and divorce. However, the result of the study suggests that there may be an association for stress degree/intensity. The RR regarding widowhood was 1,04 (0,75-1,44; p= 0,800); regarding divorce 1,03 (0,72-1,48; p=0,850), and regarding degree, intensity/frequency of stress 1,73 (0,98-3,05; p=0,059). Conclusion: There was no association of stressing life events with breast cancer. The small number of studies included, what reduced the statistical power, does not permit us to eliminate the possibility of association of stress degree/intensity and breast cancer.
Advisor:Ana Fátima Carvalho Fernandes; Marta Maria Coelho Damasceno; Thelma Leite de Araújo; João Macêdo Coelho Filho; Bernardo Lessa Horta; João Joaquim Freitas do Amaral; Cristina Maria Galvão
School:Universidade Federal do Ceará
Source Type:Master's Thesis
Life Change Events
Date of Publication:03/07/2008