Table 2.
HR (95% CI) of invasive breast cancer according to categories of total olive oil in the Nurses’ Health Study (cases = 5725), Nurses’ Health Study II (cases = 3913) and pooled data (cases = 9638).
| Never or <1 per month | >0– ≤ 4.5 g/d ( > 0 to ≤1 teaspoon) | >4.5– ≤ 7 g/d( > 1 teaspoon to ≤1/2 TBS) | >7 g/d ( > 1/2 TBS) | P-trend | HR (95% CI) for 5 g increase in olive oil intake | |
|---|---|---|---|---|---|---|
| Cumulative average intake | ||||||
| NHS | ||||||
| N° cases/Person-years | 1,546/421869 | 2,935/752465 | 536/126727 | 708/179293 | ||
| Age-adjusted model | 1 (ref.) | 1.06 (1.00, 1.13) | 1.14 (1.03, 1.26) | 1.06 (0.97, 1.17) | 0.22 | 1.01 (0.99, 1.03) |
| Multivariable model | 1 (ref.) | 1.02 (0.95, 1.09) | 1.07 (0.96, 1.19) | 0.99 (0.89, 1.09) | 0.89 | 1.00 (0.98, 1.02) |
| NHSII | ||||||
| N° cases/Person-years | 835/677172 | 2,200/1177561 | 393/185729 | 485/223253 | ||
| Age-adjusted model | 1 (ref.) | 1.20 (1.11, 1.31) | 1.24 (1.09, 1.40) | 1.23 (1.09, 1.38) | 0.03 | 1.03 (1.01, 1.05) |
| Multivariable model | 1 (ref.) | 1.08 (0.99, 1.18) | 1.08 (0.94, 1.23) | 1.04 (0.91, 1.18) | 0.81 | 1.01 (0.98, 1.03) |
| Pooled data | ||||||
| N° cases/Person-years | 2,381/1099042 | 5,135/1930025 | 929/312456 | 1,193/402546 | ||
| Age-adjusted model | 1 (ref.) | 1.11 (1.06, 1.17) | 1.17 (1.08, 1.27) | 1.12 (1.04, 1.21) | 0.02 | 1.02 (1.00, 1.04) |
| Multivariable model | 1 (ref.) | 1.04 (0.99, 1.10) | 1.07 (0.99, 1.16) | 1.01 (0.93, 1.09) | 0.81 | 1.00 (0.99, 1.02) |
| Average level of the last two measurements | ||||||
| NHS | ||||||
| N° cases/Person-years | 1,860/504057 | 2,446/622335 | 445/116566 | 974/237395 | ||
| Age-adjusted model | 1 (ref.) | 1.08 (1.01, 1.15) | 1.03 (0.92, 1.14) | 1.10 (1.01, 1.19) | 0.14 | - |
| Multivariable model | 1 (ref.) | 1.03 (0.97, 1.10) | 0.97 (0.87, 1.08) | 1.04 (0.95, 1.13) | 0.83 | - |
| NHSII | ||||||
| N° cases/Person-years | 1,106/837476 | 1,487/805866 | 402/204783 | 918/415590 | ||
| Age-adjusted model | 1 (ref.) | 1.23 (1.13, 1.33) | 1.16 (1.03, 1.30) | 1.24 (1.13, 1.36) | 0.004 | - |
| Multivariable model | 1 (ref.) | 1.14 (1.05, 1.23) | 1.04 (0.92, 1.17) | 1.10 (0.99, 1.21) | 0.81 | - |
| Pooled | ||||||
| N° cases/Person-years | 2,966/1341533 | 3,933/1428201 | 847/321350 | 1892/652984 | ||
| Age-adjusted model | 1 (ref.) | 1.13 (1.08, 1.19) | 1.08 (1.00, 1.16) | 1.16 (1.09, 1.23) | <0.01 | - |
| Multivariable model | 1 (ref.) | 1.07 (1.02, 1.13) | 1.00 (0.92, 1.08) | 1.06 (0.99, 1.13) | 0.70 | - |
Results are expressed as Hazard Ratios (HR) and 95% Confidence Intervals (95% CI).
Multivariable model: adjusted for ethnicity (white, non-white), Southern European/Mediterranean ancestry (yes, no), age at menarche ( < 12, 12, 13, 14, >14 years), menopausal status and age at menopause (premenopausal, <45, 45–49, 50–52, 53 + , unknown), postmenopausal hormone use (never user, past user, current user– estrogen only for <5 years, current user – estrogen only for ≥5 years, current estrogen + progestin user for < 5 years, current estrogen + progestin user for ≥5 years, current user of other types), oral contraceptive use history (never, ever), parity and age at first birth (nulliparous, 1 child before age 25, 1 child at ≥25 years of age, 2+ children before age 25, 2+ children ≥25 years of age), breastfeeding history (never, breastfed for ≤ 6 months, breastfed for > 6 months), family history of breast cancer (yes or no), history of biopsy-confirmed benign breast disease (yes or no), height ( < 1.60, 1.60–1.64, 1.65–1.69, 1.70–1.74, 1.75 + m), cumulatively updated total caloric intake (kcal/day, quintiles), physical activity (continuous MET-hours/week), neighborhood-based socioeconomic status indicator (continuous), BMI at age 18 ( < 20.0, 20.0–21.9, 22.0–23.9, 24.0–26.9, ≥27.0) and AHEI-2010 (without alcohol and polyunsaturated fatty acids components, quintiles).
NHS Nurses’ Health Study, NHSII Nurses’ Health Study II.