Abstract Background Eighty percent of all breast cancers and almost 90% of breast cancer deaths occur among post-menopausal women. We used a nested case control design to examine the association between nonsteroidal anti-inflammatory drug (NSAID) use and breast cancer occurrence among women over 65 years of age. The cyclooxygenase (COX)-2 enzyme is expressed more in breast cancers than in normal breast tissue. COX-2 inhibition may have a role in breast cancer prevention. Methods In the Canadian province of Quebec, physician services are covered through a governmental insurance plan. Medication costs are covered for those ≥ 65 years of age and a publicly funded screening program for breast cancer targets all women 50 years of age or older. We obtained encrypted data from these insurance databases on all women ≥ 65 years of age who filled a prescription for COX-2 inhibitors, non-selective NSAIDs (ns-NSAIDs), aspirin, or acetaminophen between January 1998 and December 2002. Cases were defined as those women who have undergone mammography between April 2001 and June 2002 and had a diagnosis of breast cancer within six months following mammography. Controls included those who have undergone mammography between April 2001 and June 2002 without a diagnosis of any cancer during the six months following mammography. The exposure of interest, frequent NSAID use, was defined as use of ns-NSAIDs and/or COX-2 inhibitors for ≥ 90 days during the year prior to mammography. Frequent use served as a convenient proxy for long term chronic use. Results We identified 1,090 cases and 44,990 controls. Cases were older and more likely to have breast cancer risk factors. Logistic regression models adjusting for potential confounders showed that frequent use of ns-NSAIDs and/or COX-2 inhibitors was associated with a lower risk of breast cancer (OR: 0.75, 95% confidence interval 0.64–0.89). Results were similar for COX-2 inhibitors (0.81, 0.68–0.97) and ns-NSAIDs (0.65, 0.43–0.99), when assessed separately. Frequent use of aspirin at doses > 100 mg/day in the year prior to mammography was also associated with a lower risk of breast cancer (0.75, 0.64–0.89). However, use of aspirin at doses ≤ 100 mg/day did not have any association with breast cancer (0.91, 0.71–1.16). Conclusion Women who use NSAIDs or doses of aspirin > 100 mg frequently may have a lower risk of breast cancer.
Researchers increasingly use meta-analysis to synthesize the results of several studies in order to estimate a common effect. When the outcome variable is continuous, standard meta-analytic approaches assume that the primary studies report the sample mean and standard deviation of the outcome. However, when the outcome is skewed, authors sometimes summarize the data by reporting the sample median and one or both of (i) the minimum and maximum values and (ii) the first and third quartiles, but do not report the mean or standard deviation. To include these studies in meta-analysis, several methods have been developed to estimate the sample mean and standard deviation from the reported summary data. A major limitation of these widely used methods is that they assume that the outcome distribution is normal, which is unlikely to be tenable for studies reporting medians. We propose two novel approaches to estimate the sample mean and standard deviation when data are suspected to be non-normal. Our simulation results and empirical assessments show that the proposed methods often perform better than the existing methods when applied to non-normal data. ; anadian Institutes of Health Research (CIHR) KRS-134297 Fonds de recherche du Quebec -Sante (FRQS) Canadian Institutes of Health Research (CIHR) Canadian Institutes of Health Research (CIHR) FRQS Masters Training Awards Vanier Canada Graduate Scholarship FRQS Postdoctoral Training Fellowship Research Institute of the McGill University Health Centre G.R. Caverhill Fellowship from the Faculty of Medicine, McGill University Cumming School of Medicine, University of Calgary Alberta Health Services through the Calgary Health Trust Hotchkiss Brain Institute Senior Health Scholar award from Alberta Innovates Health Solutions Health Research Council of New Zealand Lundbeck International Tehran University of Medical Sciences M-288 Department of Education, National Institute on Disability and Rehabilitation Research, Spinal Cord Injury Model Systems: University of Washington H133N060033 Baylor College of Medicine H133N060003 University of Michigan System H133N060032 National Health and Medical Research Council of Australia 1002160 Safe Work Australia Australian Research Council FT130101444 European Foundation for Study of Diabetes Chinese Diabetes Society Lilly Foundation Asia Diabetes Foundation Liao Wun Yuk Diabetes Memorial Fund United States National Institute of Mental Health (NIMH) grant 5F30MH096664 United States Department of Health & Human Services National Institutes of Health (NIH) - USA United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH Fogarty International Center (FIC) United States Department of Health & Human Services National Institutes of Health (NIH) - USA National Cancer Center United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Heart Lung & Blood Institute (NHLBI) NIH Office of Research for Women's Health through the Fogarty Global Health Fellows Program Consortium 1R25TW00934001 American Recovery and Reinvestment Act United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute of Mental Health (NIMH) R24MH071604 / R34 MH072925/ K02 MH65919 / P30 DK50456 / R24 MH56858 / RO1 MH073687 /RO1-MH069666 / R34MH084673 /R24 MH071604 United States Department of Health & Human Services Centers for Disease Control & Prevention - USA R49 CE002093 St Anne's Community Services, Leeds, UK US National Center for Medical Rehabilitation Research RO1 HD39415 Federal Ministry of Education & Research (BMBF) 01GY1150 United States Department of Health & Human Services National Institutes of Health (NIH) - USA T37 MD001449 / T32 GM07356 Ohio Board of Regents Research and Development Administration Office, University of Macau MYRG2015-00109-FSS Federal Ministry of Education & Research (BMBF) 01 GD 9802/4 ; 01 GD 0101 Federation of German Pension Insurance Institute Federal Ministry of Education & Research (BMBF) Perpetual Trustees Flora and Frank Leith Charitable Trust Jack Brockhoff Foundation Grosvenor Settlement Sunshine Foundation Danks Trust Canadian Institutes of Health Research (CIHR) FRN 83518 Scleroderma Society of Canada Scleroderma Society of Ontario Scleroderma Society of Saskatchewan Sclerodermie Quebec Cure Scleroderma Foundation Inova Diagnostics Inc Euroimmun FRQS Canadian Arthritis Network Lady Davis Institute of Medical Research of the Jewish General Hospital, Montreal, QC FRQS Senior Investigator Award National Strategic Reference Framework European Union (EU) Greek Ministry of Education, Lifelong Learning and Religious Affairs (ARISTEIA-ABREVIATE) 1259 Ministry of Health, Labour and Welfare, Japan UK National Institute for Health Research under its Programme Grants for Applied Research Programme RP-PG-0606-1142 Canada Research Chair in Neurological Health Services Research AIHS Population Health Investigator Award National Health and Medical Research Council of Australia 1088313 Netherlands Organization for Health Research and Development 945-03-047 National Health Research Institutes - Taiwan NHRI-EX97-9706PI Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand 49086 Reitoria de Pesquisa da Universidade de Sao Paulo 09.1.01689.17.7 Banco Santander 10.1.01232.17.9 Pfizer medical faculty of the University of Heidelberg, Germany 121/2000 Research University Grant Scheme from Universiti Putra Malaysia, Malaysia Postgraduate Research Student Support Accounts of the University of Auckland, New Zealand National Program for Centers of Excellence (PRONEX/FAPERGS/CNPq, Brazil) Pfizer US Pharmaceutical Inc. PQ-CNPq-2 301321/2016-7 Belgian Ministry of Public Health and Social Affairs Pfizer Ministry of Health, Italy UK National Health Service Lothian Neuro-Oncology Endowment Fund Universiti Sains Malaysia United States Department of Health & Human Services United States Health Resources & Service Administration (HRSA) R40MC07840 United States Department of Health & Human Services Agency for Healthcare Research & Quality R36 HS018246 United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Center for Research Resources (NCRR) TL1 RR024135 University of Melbourne Hunter Medical Research Institute Innovatiefonds Zorgverzekeraars Netherlands Organization for Health Research and Development (ZonMw) Mental Health Program 100.003.005 100.002.021 Academic Medical Center/University of Amsterdam Fund for Innovation and Competitiveness of the Chilean Ministry of Economy, Development and Tourism, through the Millennium Scientific Initiative IS130005 US Department of Veteran Affairs US Department of Veteran Affairs United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Heart Lung & Blood Institute (NHLBI) R01 HL079235 American Federation for Ageing Research Robert Wood Johnson Foundation (RWJF) Ischemia Research and Education Foundation
