Table 4.
Characteristics of included studies in meta-analysis.
| First author (published year) | Region | Menopausal status | Study design | Year subjects were recruited | Sample size, case/control | Type of tumor | Risk factorsa | Matched factor | Adjusted factorsb | Rank (Number of qualified items)c |
|---|---|---|---|---|---|---|---|---|---|---|
| Bao et al. 2011.18 | China | total/pre/post | PCC | 1996–1998/2002–2005 | 2676/3474 | ER+/PR+, ER−/PR−, ER+/PR−, ER−/PR+ | B,C,D,E,F | age | 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. | A (6) |
| Islam et al. 2012.25 | Japan | total | HCC | 2003–2005 | 706/1412 | Luminal, HER2-enriched, TN | B,C,D,E,F | age, menopausal status | 1, 4, 5, 6, 13, 17, 18 | B (5) |
| Sueta et al. 2012.28 | Japan | total/pre/post | HCC | 2001–2005 | 715/1430 | Luminal, HER2-enriched, TN | A | age, menopausal status | 1, 4, 5, 9, 12, 13, 14,15,16. | B (5) |
| Kawai et al. 2012.26 | Japan | total | HCC | 1997–2009 | 1092/3160 | ER+/PR+,ER−/PR−, ER+/PR−,ER−/PR+ | A,B,C,D,E | – | 1, 5, 6,17,18, 19,20, 21. | A (6) |
| Miyagawa et al. 2013.27 | Japan | total/pre/post | PCC | 2005–2012 | 615/682 | Luminal A, Luminal B, HER2-enriched, TN | C | – | 1,4,9,12,22 | B (5) |
| Xing et al. 2009.19 | China | total | PCC | 2001–2009 | 1417/1587 | Luminal A, Luminal B, HER2-enriched, TN | B,C,D,E | age | 1,4,9,12,13,23,24,25 | B (4) |
| Present study | China | total/pre/post | PCC | 2002–2012 | 1416/1256 | Luminal, HER2-enriched, TN | A,B,C,D,E,F | age | 1,6,9,12,13,14,22, 26 | – |
ER, estrogen receptor; HCC, hospital-based case-control study; PCC, population-based case-control study; PR. progesterone receptor; TN, triple-negative.
Risk factors included in this meta-analysis: A. BMI B. age at menarche C. parity D. age at first live birth E. breastfeeding F. menopausal age.
Risk factors adjusted for in the studies: 1. age, 2. education, 3. history of breast fibroadenoma, 4. family history of breast cancer, 5. physical exercise, 6. BMI, 7. waist-to-hip ratio, 8. history of live birth, 9. parity, 10. study phase, 11. years of menstruation, 12. age at menarche, 13. menopausal status, 14. age at first live birth, 15. hormone use, 16. referral pattern, 17. smoking, 18. alcohol use, 19. occupation, 20. year of recruitment, 21. area of residence, 22. age at menopause, 23. induced abortion, 24. spontaneous abortion, 25. history of hysteromyoma, and 26. breastfeeding.
Results of quality assessment and number of qualified items according to the Newcastle-Ottawa Quality Assessment Scale (NOS) for case-control studies.