Table 2 Main characteristics of case-only studies included in the meta-analysis
S.no | First author, year (ref) | Study design | Region | Adj: variables adjusted | Type of BC Invasive or invasive and DCIS | Mammographic density categories [no/little, low, medium, high] | Age at breast cancer diagnosis Mean (SD) or range | Breast cancer cases (n) | Quality score by MINOS |
|---|---|---|---|---|---|---|---|---|---|
1 | Li, 2017 [21] | Retrospective | Kunming | Age, menopausal status, and other variables. | Invasive breast cancer only | BI-RADSb [1 + 2,3 + 4] | 22 ~ 69 | 69 41:28 (premenopausal: postmenopausal) | 6 |
2 | Li, 2019 [23] | Retrospective | Beijing | Age, BMI, menopausal status, parity, and other variables. | Invasive breast cancer only | BI-RADSb [1 + 2,3,4] | 51.7 (10.7) | 1779 889:890 (premenopausal: postmenopausal) | 7 |
3 | Zhao, 2020 [14] | Retrospective | Harbin | Not formally age-adjusted. | Invasive breast cancer only | BI-RADSa [1 + 2,3 + 4] | 25 ~ 69 47 (NK) | 119 68:51 (premenopausal: postmenopausal) | 6 |
4 | Ji, 2021 [26] | Retrospective | Tianjin | Age. | Both | BI-RADSb [1, 2, 3, 4] | 19 ~ 93 54.3 (11.2) | 9716 4892:4824 (premenopausal: postmenopausal) | 6 |