Brassiere wearing and breast cancer risk : a systematic review and meta-analysis

AIM: To evaluate existing evidence for the association between different type of brassiere exposures and the risk of breast cancer.||METHODS: Ovid Medline, CINAHL, Cochrane Data Base of Systematic Reviews, Pubmed, Scopus, Proquest, Sciencedirect, Wiley Online Library, WanF ang Data, Hong Kong Index to Chinese Periodicals,China Journal Net,Chinese Medical Current Contents, Chinese Biomedical Literature Database, China Academic Journals FullText database, Taiwan Electronic Periodical Services and HyR ead; reference lists of published studies; original research studies published in English or Chinese examining the association between type and duration of brassiere-wearing and breast cancer risk. Data were abstracted by a first reviewer and verified by a second. Study quality was rated according to predefined criteria."Fair" or "good" quality studies were included. Results were summarised by meta-analysis whenever adequate material was available.||RESULTS:Twelve case-control studies were included in the review.Meta-analysis showed brassiere wearing during sleep was associated with a 1.3 times of increased risk. The odd ratio for more than 12 h of daily brassiere use in relation to breast cancer risk was 1.08(95%CI:1.01-1.14).||CONCLUSION:The present review demonstrates insufficient evidence to establish a positive association between the duration and type of brassiere wearing and breast cancer.Further research is essential; specifically,a large-scale epidemiological study of a better design is needed to examine the association between various forms of brassiere exposure in detail and breast cancer risk,with adequate control of confounding variables.