TABLE 3.
Odds ratios (95% confidence intervals) for the associations between serum PFOS and PFOA levels and risk of ER+/PR+ breast cancer, stratified by time to diagnosis or time since menopause
| PFASa | Time from blood draw to diagnosis | Time from menopause to blood draw | ||||
|---|---|---|---|---|---|---|
| <6 years (n = 152) |
≥6 years (n = 139) |
P het b | ≤15 years (n = 146) |
>15 years (n = 145) |
P het b | |
| PFOS | ||||||
| Quartile 1 | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | ||
| Quartile 2 | 1.40 (0.61–3.19) | 1.48 (0.59–3.73) | 1.42 (0.34–5.99) | 1.27 (0.42–3.81) | ||
| Quartile 3 | 2.02 (0.86–4.73) | 4.72 (1.66–13.47) | 2.45 (0.40–15.13) | 3.28 (0.93–11.56) | ||
| Quartile 4 | 1.28 (0.47–3.42) | 3.67 (1.20–11.25) | 2.72 (0.45–16.56) | 1.89 (0.53–6.80) | ||
| Ptrendc | .66 | .02 | .45 | .25 | .26 | .36 |
| PFOA | ||||||
| Quartile 1 | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | 1.00 (Ref) | ||
| Quartile 2 | 1.14 (0.49–2.66) | 1.31 (0.53–3.24) | 1.47 (0.31–7.02) | 1.00 (0.34–2.92) | ||
| Quartile 3 | 1.39 (0.58–3.30) | 1.02 (0.36–2.91) | 2.41 (0.36–16.10) | 0.92 (0.29–2.86) | ||
| Quartile 4 | 1.50 (0.52–4.38) | 0.53 (0.17–1.70) | 0.36 (0.03–3.75) | 0.81 (0.20–3.28) | ||
| Ptrendc | .48 | .15 | .46 | .22 | .74 | .81 |
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.
Quartiles are based on the distribution of PFOS or PFOA levels among controls.
P-values for heterogeneity of associations across strata, estimated using a Wald test for a cross-product term between time to diagnosis or time since menopause 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.