Pelvic inflammatory disease and the risk of ovarian cancer: a meta-analysis.
OBJECTIVE
Previous studies on pelvic inflammatory disease (PID) and the risk of ovarian cancer have found inconsistent results. We performed an updated meta-analysis to summarize the evidence of this association.


METHODS
PubMed, Embase, and ISI web of science databases were searched through October 2016 for studies that investigated the PID and ovarian cancer association. Summary risk estimates were calculated using random-effects meta-analysis.


RESULTS
Thirteen studies were eligible for analysis, which included six cohort studies and seven case-control studies. PID was associated with an increased risk of ovarian cancer overall [relative risk (RR) 1.24, 95% CI 1.06-1.44; I2= 58.8%]. In analyses stratified by race, a significant positive association was observed in studies conducted among Asian women (RR 1.69, 95% CI 1.22-2.34; I2= 0%), but marginally significant among Caucasians (RR 1.18, 95% CI 1.00-1.39; I2= 60.7%).Risk estimates were elevated in both cohort (RR1.32; 95% CI 1.05-1.66; I2= 64.7%) and case-control studies (RR 1.17; 95% CI 0.93-1.49; I2= 57.6%), albeit not statistically significant in case-control studies.


CONCLUSIONS
Our results suggested that PID might be a potential risk factor of ovarian cancer, with pronounced associations among Asian women. Large and well-designed studies with objective assessment methods, such as hospital records, are needed to confirm the findings of this meta-analysis.
Faculty of Medicine, School of Public Health and Primary Care, The Chinese University of Hong Kong, Room 508, 5/F, School of Public Health, Prince of Wales Hospital, Shatin, N.T., Hong Kong, China.|Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
Zhiyi
Z
Zhou
Guangdong Provincial Key Laboratory of Food, Nutrition and Health, School of Public Health, Sun Yat-sen University, Guangzhou, 510080, China.
Fangfang
F
Zeng
Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
Jianhui
J
Yuan
Faculty of Medicine, School of Public Health and Primary Care, The Chinese University of Hong Kong, Room 508, 5/F, School of Public Health, Prince of Wales Hospital, Shatin, N.T., Hong Kong, China.|The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
Jinling
J
Tang
Alvin J. Siteman Cancer Center and Department of Surgery, Washington University School of Medicine, 660 S Euclid Ave, St Louis, MO, 63110, USA.
Graham A
GA
Colditz
Channing Division of Network Medicine, Harvard Medical School and the Brigham and Women's Hospital, 181 Longwood Ave., 3rd Fl., Boston, MA, 02115, USA.|Department of Epidemiology, Harvard T. H. Chan School of Public Health, 677 Huntington Avenue, Boston, MA, 02115, USA.
Shelley S
SS
Tworoger
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, NCI Shady Grove, 9609 Medical Center Drive, MSC 9774, Bethesda, MD, 20892, USA. britton.trabert@nih.gov.
Britton
B
Trabert
Faculty of Medicine, School of Public Health and Primary Care, The Chinese University of Hong Kong, Room 508, 5/F, School of Public Health, Prince of Wales Hospital, Shatin, N.T., Hong Kong, China. xuefensu@cuhk.edu.hk.|The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China. xuefensu@cuhk.edu.hk.
Xuefen
X
Su
D044466:Asian People; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000209:etiology*; D000292:Pelvic Inflammatory Disease / Q000150:complications*; D012307:Risk Factors; D044465:White People
Inflammation; Meta-analysis; Ovarian cancer; Pelvic inflammatory disease