Table 3.
Association between dietary inflammatory index, dietary oxidative balance score, and risk of breast cancer
| Index score quartiles | P for trend | Continuous 1 SD increment | ||||||
|---|---|---|---|---|---|---|---|---|
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |||||
| Person-years | 92605 | 92278 | 91571 | 89960 | 366414 | |||
| Dietary inflammatory index | Total breast cancer | No. of cases | 692 | 663 | 648 | 616 | 2619 | |
| Model 1, HR (95%CI)1 | 1 (ref) | 0.99 (0.88–1.10) | 1.01 (0.90–1.12) | 1.02 (0.91–1.14) | 0.37 | 1.00 (0.96–1.05) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 0.98 (0.88–1.09) | 0.99 (0.89–1.11) | 1.01 (0.90–1.13) | 0.80 | 1.00 (0.96–1.04) | ||
| ER+ breast cancer | No. of cases | 534 | 509 | 497 | 421 | 1961 | ||
| Model 1, HR (95%CI)1 | 1 (ref) | 0.99 (0.87–1.11) | 1.01 (0.89–1.14) | 0.91 (0.80–1.04) | 0.60 | 0.96 (0.92–1.01) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 0.98 (0.87–1.11) | 1.00 (0.89–1.14) | 0.93 (0.81–1.07) | 0.64 | 0.97 (0.92–1.02) | ||
| ER − breast cancer | No. of cases | 78 | 88 | 77 | 88 | 331 | ||
| Model 1, HR (95%CI)1 | 1 (ref) | 1.15 (0.84–1.56) | 1.03 (0.75–1.42) | 1.24 (0.90–1.71)* | 0.37 | 1.07 (0.96–1.19) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 1.15 (0.85–1.56) | 1.05 (0.76–1.44) | 1.30 (0.94–1.79)* | 0.30 | 1.09 (0.97–1.22) | ||
| Triple − breast cancer | No. of cases | 39 | 44 | 44 | 55 | 182 | ||
| Model 1, HR (95%CI)1 | 1 (ref) | 1.14 (0.74–1.75) | 1.17 (0.75–1.80) | 1.49 (0.97–2.30) | 0.27 | 1.17 (1.02–1.35) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 1.14 (0.74–1.75) | 1.17 (0.76–1.80) | 1.53 (0.99–2.35) | 0.26 | 1.18 (1.03–1.36) | ||
| Quartile 1 | Quartile 2 | Quartile 3 | Quartile 4 | |||||
| Person-years | 87843 | 96201 | 90774 | 91596 | 366414 | |||
| Dietary oxidative balance score | Total breast cancer | No. of cases | 611 | 677 | 666 | 665 | 2619 | |
| Model 1, HR (95%CI)1 | 1 (ref) | 0.96 (0.86–1.07) | 0.97 (0.87–1.08) | 0.91 (0.81–1.03) | 0.23 | 0.97 (0.93–1.01) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 0.96 (0.86–1.07) | 0.97 (0.86–1.08) | 0.92 (0.81–1.03) | 0.23 | 0.97 (0.93–1.01) | ||
| ER+ breast cancer | No. of cases | 428 | 516 | 511 | 506 | 1961 | ||
| Model 1, HR (95%CI)1 | 1 (ref) | 1.05 (0.92–1.19) | 1.06 (0.93–1.21) | 0.99 (0.86–1.13) | 0.68 | 0.99 (0.95–1.04) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 1.03 (0.90–1.17) | 1.03 (0.90–1.18) | 0.96 (0.83–1.10) | 0.98 | 0.98 (0.94–1.03) | ||
| ER − breast cancer | No. of cases | 82 | 77 | 85 | 87 | 331 | ||
| Model 1, HR (95%CI)1 | 1 (ref) | 0.83 (0.60–1.14) | 0.95 (0.70–1.30) | 0.95 (0.69–1.31) | 0.54 | 0.99 (0.88–1.11) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 0.82 (0.60–1.12) | 0.93 (0.68–1.27) | 0.93 (0.67–1.28) | 0.43 | 0.98 (0.87–1.09) | ||
| Triple − breast cancer | No. of cases | 51 | 46 | 44 | 41 | 182 | ||
| Model 1, HR (95%CI)1 | 1 (ref) | 0.81 (0.54–1.21) | 0.81 (0.54–1.23) | 0.74 (0.48–1.15) | 0.16 | 0.88 (0.76–1.02) | ||
| Model 2, HR (95%CI)2 | 1 (ref) | 0.81 (0.54–1.21) | 0.81 (0.54–1.22) | 0.74 (0.48–1.15) | 0.15 | 0.88 (0.76–1.02) | ||
Adjusted for age (age as the primary time scale)
Adjusted for race/ethnicity (non-Hispanic White, non-Hispanic Black, or other than White or Black), educational attainment (high school degree or less, some college, or college degree or higher), baseline menopausal status (binary), body mass index (BMI, continuous), interaction term between baseline menopausal status and BMI, physical activity (MET-hours/week, quintiles), smoking status (≥20 pack-years, <20 and ≥10 pack-years, <10 and >0 pack-years, or never smoker), ever use of hormonal birth control, hormone therapy (none, estrogen only, or both estrogen and progesterone), recent mammogram screening (<1, 1–2, or > 2 years or never had a mammogram), number of first-degree relatives diagnosed with breast cancer before age 50 years (0, 1, or ≥2), use of aspirin (never, tertiles of lifetime cumulative doses, or missing), and use of non-aspirin NSAIDS (never, tertiles of lifetime cumulative doses, or missing).
HR for ER– breast cancer was significantly different from ER+ breast cancer in case–case analysis (P<0.05).
Abbreviation: SD, standard deviation; HR, hazard ratio; 95% CI, 95% confidence interval; ER, estrogen receptor; +, positive; −, negative.