From: Intrauterine environments and breast cancer risk: meta-analysis and systematic review
Type of study | Author | Year | Design | Cases | Controls (or cohort) | Country/place of study | Gestational age (weeks) | OR (95% CI) | Comments |
---|---|---|---|---|---|---|---|---|---|
Case-control studies | [42]a | 1988 | PCC | 153 | 461 | USA | 25–32 | 1.16 (0.50–1.54) | Matched analysis |
 |  |  |  |  |  |  | 33–40 | Referent |  |
 | [13]b | 1996 | NCC | 571 | 1,525 | USA | Categorical |  | Adjusted for age |
 |  |  |  |  |  |  |    40 | Referent |  |
 |  |  |  |  |  |  |    38–39 | 0.76 (0.44–1.32) |  |
 |  |  |  |  |  |  |    36–37 | 0.96 (0.59–1.56) |  |
 |  |  |  |  |  |  | Binomial |  |  |
 |  |  |  |  |  |  |    ≥ 37 | Referent |  |
 |  |  |  |  |  |  |    ≤ 36 | 0.82 (0.37–1.82) |  |
 | [14] | 1996 | PCC | 1123 | 1371 | USA | Nonpreterm | Referent | Adjusted for age, menopausal status, and maternal smoking |
 |  |  |  |  |  |  | Preterm | 1.1 (0.5–2.1) |  |
 | [32]a | 1997 | NCC | 1,010 | 2,625 | Sweden | ≥ 33 | Referent | Adjusted for maternal age, matermal socioeconomic status, maternal parity, maternal pre-eclampsia or eclampsia, neonatal jaundice, severe prematurity, twin, and birth weight |
 |  |  |  |  |  |  | ≤ 32 | 3.96 (1.46–10.81) |  |
 | [33]b | 1998 | PCC | 502 | 433 | USA | ≥ 43 | 1.5 (0.8–2.6) | Crude ORs |
 |  |  |  |  |  |  | 37–42 | Referent |  |
 |  |  |  |  |  |  | ≤ 36 | 0.9 (0.5–1.8) |  |
 | [15]a,b | 2000 | LCC | 480 | 2,854 | USA | ≥ 37 | Referent | Crude ORs |
 |  |  |  |  |  |  | 33–36 | 1.34 (0.85–2.13) |  |
 |  |  |  |  |  |  | ≤ 32 | 0.55 (0.19–1.57) |  |
 | [34]a,b | 2001 | LCC | 87 | 87 | Sweden | ≥ 40 | 8.4 (1.3–54.4) | Matched analysis by conditional logistic regression |
 |  |  |  |  |  |  | 37–40 | 3.4 (0.7–17.0) |  |
 |  |  |  |  |  |  | 33–36 | 3.5 (0.7–17.5) |  |
 |  |  |  |  |  |  | ≤ 32 | Referent |  |
 | [25]a | 2003 | LCohort | 127 | (1,483) | Sweden | ≥ 33 | 1.08 (0.64–1.70) | Standardized incidence ratio (expected/observed) |
 |  |  |  |  |  |  | ≤ 32 | 0.92 (0.57–1.41) |  |
 | [45]a,b | 2004 | LCC | 2,471 | 9,801 | USA | ≥ 37 | Referent | Adjusted for age and maternal age at first birth |
 |  |  |  |  |  |  | 32–36 | 0.91 (0.72–1.13) |  |
 |  |  |  |  |  |  | ≤ 31 | 1.43 (0.90–2.28) |  |
 | [20]b | 2005 | PCC | 1,424 | 1,457 | Poland | ≥ 37 | Referent | Adjusted for age, education, age at menarche, menopausal status and age at menopause, age at first full-term pregnancy, number of full-term pregnancies, family history of breast cancer among first-degree relatives, mammography screening, and current body mass index |
 |  |  |  |  |  |  | ≤ 36 | 1.01 (0.75–1.32) |  |
Cohort studies | [62]c | 2000 | LCohort | 12 | 273 | Sweden | 35 | 0.2 (0.01–1.3) | Standardized incidence ratio |
 |  |  |  |  |  |  | 33–34 | 0.7 (0.1–2.0) |  |
 |  |  |  |  |  |  | 31–32 | 2.3 (0.7–5.3) |  |
 |  |  |  |  |  |  | <31 | 6.7 (1.4–19.5) |  |
 | [16]c | 2001 | LTCCS | 2,265 | 9,060 | Sweden | 33–36 | Referent | Crude ORs |
 |  |  |  |  |  |  | 37–38 | 1.8 (0.83–4.0) |  |
 |  |  |  |  |  |  | 40–44 | 2.0 (0.88–4.6) |  |
 | [29]c | 2005 | LCohort | 367 | 5,346 | Sweden | 1 week increase | <50 years |  |
 |  |  |  |  |  |  |  | 0.94 (0.83–1.07) |  |
 | [40]c | 2006 | Cohort | 97 | 5,847 | USA | <39 | 0.77 (0.42–1.4) | Adjusted for age |
 |  |  |  |  |  |  | 39 | 1.38 (0.78–2.4) |  |
 |  |  |  |  |  |  | 40 | Referent |  |
 |  |  |  |  |  |  | 41+ | 1.33 (0.67–2.6) |  |
 | [31]b | 2006 | Cohort | 249 | 1024 | USA | ≥ 43 | 0.7 (0.2–2.7) | Adjusted for: age at diagnosis, diagnosis year, stage at diagnosis, and birth order, with exception of birth order, which is adjusted for maternal age |
 |  |  |  |  |  |  | 37–42 | Referent |  |
 |  |  |  |  |  |  | <37 | 1.4 (0.7–2.9) |  |
 |  |  |  |  |  |  |  | P for trend = 0.3 |  |