TABLE 2.
Odds ratios (95% confidence intervals) for the associations between serum PFOS and PFOA levels and risk of postmenopausal breast cancer according to hormone receptor status
| PFASb | ER status | PR status | ER/PR statusa | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| ER+ (n = 435) |
ER− (n = 147) |
P het c | PR+ (n = 299) |
PR− (n = 241) |
P het c | ER+/PR+ (n = 291) |
ER+/PR− (n = 98) |
ER−/PR− (n = 138) |
P het c | |
| PFOS | ||||||||||
| Quartile 1 | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | |||
| Quartile 2 | 1.26 (0.81–1.95) | 0.98 (0.39–2.47) | 1.55 (0.90–2.67) | 1.00 (0.52–1.92) | 1.46 (0.84–2.54) | 0.79 (0.19–3.38) | 1.01 (0.38–2.63) | |||
| Quartile 3 | 1.59 (1.01–2.50) | 1.13 (0.49–2.62) | 2.34 (1.29–4.23) | 0.91 (0.50–1.64) | 2.19 (1.21–3.98) | 0.32 (0.08–1.32) | 1.12 (0.48–2.62) | |||
| Quartile 4 | 1.29 (0.77–2.15) | 0.52 (0.18–1.55) | 1.79 (0.92–3.48) | 0.61 (0.29–1.31) | 1.89 (0.97–3.69) | 0.32 (0.06–1.86) | 0.60 (0.19–1.83) | |||
| Ptrendd | .39 | .20 | .71 | .14 | .15 | .66 | .08 | .12 | .34 | .25 |
| PFOA | ||||||||||
| Quartile 1 | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | |||
| Quartile 2 | 1.07 (0.68–1.66) | 0.84 (0.36–1.95) | 1.14 (0.66–1.96) | 0.90 (0.47–1.70) | 1.14 (0.66–1.97) | 1.40 (0.32–6.11) | 0.90 (0.38–2.10) | |||
| Quartile 3 | 1.01 (0.64–1.61) | 2.08 (0.85–5.07) | 1.02 (0.57–1.83) | 2.05 (1.06–3.94) | 0.99 (0.55–1.80) | 1.88 (0.55–6.42) | 2.23 (0.90–5.54) | |||
| Quartile 4 | 1.03 (0.61–1.75) | 1.63 (0.63–4.20) | 0.77 (0.39–1.52) | 1.48 (0.75–2.93) | 0.81 (0.40–1.62) | 1.63 (0.45–5.87) | 1.62 (0.62–4.23) | |||
| Ptrendd | .96 | .19 | .30 | .31 | .15 | .21 | .41 | .50 | .21 | .44 |
Notes: Odds ratios and 95% confidence intervals were estimated from conditional logistic regression models adjusted for age at blood draw (continuous; years), study center (Upper Midwest [Wisconsin and Minnesota], West/South [Colorado, Hawaii, Missouri, Utah, and Alabama], East [Washington DC, Michigan, and Pennsylvania]), race/ethnicity (non-Hispanic White, non-Hispanic Black, other), education (high school graduate or less, post-high school training or some college, college graduate or postgraduate), age at menarche (<12, 12–13, ≥14 years), age at first live birth and number of live births (nulliparous, <20 years and ≥1 birth, 20–29 years and 1–2 births, 20–29 years and ≥3 births, ≥30 years and ≥1 birth), age at menopause (<45, 45–49, 50–54, ≥55 years), duration of MHT use (never, ≤1, 2–5, 6–9, ≥10 years), first-degree family history of female breast cancer (no/unknown, yes), personal history of benign breast disease (no/unknown, yes), body mass index (<25, 25 to <30, ≥30 kg/m2), smoking status (never, former, current), vigorous physical activity (<1, 1–3, ≥4 hours/week, missing), and natural log-transformed levels of PFOA (for PFOS models) or PFOS (for PFOA models). Models conditioned on case-control matched pairs, with controls individually matched to cases on age at baseline (±2 years), date of blood draw (±3 months), and MHT use at baseline.
Bold indicates statistical significance at P < .05.
Abbreviations: ER, estrogen receptor; MHT, menopausal hormone therapy; PFAS, per- and polyfluoroalkyl substances; PFOA, perfluorooctanoate; PFOS, perfluorooctane sulfonate; PR, progesterone receptor.
ER−/PR+ cases were not analyzed due to small numbers (n = 6).
Quartiles are based on the distribution of PFOS or PFOA levels among controls.
P-values for heterogeneity of associations across tumor subtypes, estimated using a Wald test for a cross-product term between hormone receptor status (ER, PR, or ER/PR status for each matched case-control pair) and serum PFOS or PFOA levels (continuous variable based on quartile-specific median values).
Tests for linear trend across quartiles performed by modeling quartile-specific median values of PFOS or PFOA among the controls as a continuous variable.