Table 1. Description of GWAS datasets and instrumental variables used in our study.
| Phenotype | IV | Sample size | Ethnicity | Consortium | R2 | F-statistics | Author, Year |
|---|---|---|---|---|---|---|---|
| Exposures | |||||||
| BMI | 281 | 434,794 females | European | Genetic Investigation of ANthropometric Traits (GIANT) and UK BioBank | 0.040 | 63.799 | Pulit, 2019 |
| WHR | 203 | 381,152 females | European | Genetic Investigation of ANthropometric Traits (GIANT) and UK BioBank | 0.040 | 78.191 | Pulit, 2019 |
| WHRadjBMI | 266 | 379,501 females | European | Genetic Investigation of ANthropometric Traits (GIANT) and UK BioBank | 0.036 | 53.242 | Pulit, 2019 |
| childhood BMI | 25 | 39,620 | European | Early Growth Genetics (EGG) | 0.036 | 58.975 | Vogelezang, 2020 |
| Outcomes | |||||||
| BC overall | 170 | 133,384 cases / 113,789 controls | European | Breast Cancer Association Consortium (BCAC) | 0.067 | 104.867 | Zhang, 2020 |
| ER+ | NA | 69,501 cases / 105,974 controls | European | Breast Cancer Association Consortium (BCAC) | NA | NA | Michailidou, 2017 |
| ER- | NA | 21,468 cases / 105,974 controls | European | Breast Cancer Association Consortium (BCAC) | NA | NA | Michailidou, 2017 |
| Confounders | |||||||
| AAM | 375 | 329,345 | European | Reproductive Genetics (ReproGen) | 0.074 | 67.656 | Day, 2017 |
| ANM | 290 | 201,323 | European | Reproductive Genetics (ReproGen) | 0.130 | 103.187 | Ruth, 2021 |
| Smoking | 378 | 1,232,091 | European | GWAS & Sequencing Consortium of Alcohol and Nicotine (GSCAN) | 0.023 | 77.222 | Liu, 2019 |
| Drinking | 99 | 941,280 | European | GWAS & Sequencing Consortium of Alcohol and Nicotine (GSCAN) | 0.002 | 17.811 | Liu, 2019 |
Abbreviations: GWAS, genome-wide association study; IV, instrumental variable; BMI, body mass index; WHR, waist-to-hip ratio; WHRadjBMI, waist-to-hip ratio adjusted for body mass index; BC, breast cancer; ER, estrogen receptor; AAM, age at menarche; ANM, age at natural menopause.