Table 2. Hazard ratios (HR) and 95% confidence intervals (95% CI) of breast cancer death by vitamin C intake among 3405 invasive breast cancer cases in the Swedish Mammography Cohort.
|
Quartile of vitamin C intake (mg d−1) |
|
||||
|---|---|---|---|---|---|
| <42.9 | 42.9–65.5 | 65.6–92.4 | ⩾92.5 | Ptrenda | |
| Person-years |
7458 |
7523 |
7584 |
7516 |
— |
| Breast cancer deaths |
128 |
103 |
97 |
88 |
— |
| Age-adjusted model | 1.00 | 0.80 (0.62–1.04) | 0.75 (0.58–0.98) | 0.69 (0.52–0.90) | 0.007 |
| Covariate-adjusted modelb | 1.00 | 0.84 (0.65–1.09) | 0.81 (0.62–1.06) | 0.74 (0.57–0.98) | 0.04 |
| Covariate-adjusted model+clinical characteristicsc |
1.00 |
0.89 (0.69–1.16) |
0.77 (0.59–1.01) |
0.75 (0.57–0.99) |
0.03 |
| Non-breast cancer deaths |
192 |
145 |
153 |
149 |
|
| Age-adjusted model | 1.00 | 0.81 (0.65–1.00) | 0.93 (0.75–1.15) | 0.90 (0.72–1.11) | 0.58 |
| Covariate-adjusted modelb | 1.00 | 0.83 (0.67–1.03) | 0.96 (0.77–1.19) | 0.92 (0.74–1.14) | 0.70 |
| Covariate-adjusted model+clinical characteristicsc |
1.00 |
0.84 (0.68–1.05) |
0.97 (0.78–1.20) |
0.91 (0.73–1.13) |
0.65 |
| Total deaths |
320 |
248 |
250 |
237 |
|
| Age-adjusted model | 1.00 | 0.80 (0.68–0.95) | 0.85 (0.72–1.00) | 0.80 (0.68–0.95) | 0.03 |
| Covariate-adjusted modelb | 1.00 | 0.84 (0.71–0.99) | 0.90 (0.76–1.06) | 0.85 (0.71–1.00) | 0.12 |
| Covariate-adjusted model+clinical characteristicsc | 1.00 | 0.86 (0.72–1.01) | 0.89 (0.75–1.05) | 0.84 (0.71–1.00) | 0.08 |
Determined using category medians.
Cox proportional hazard model adjusted for age (continuous), energy intake (continuous), education level (primary, high school, university), marital status (single, married, divorced, widowed, living with partner), menopausal status at diagnosis, (premenopausal, postmenopausal, unknown), body mass index (<20, 20–24.9, 25–29.9, ⩾30 kg m−2), alcohol intake (non-drinker, <3.4, 3.4–9.9, ⩾10 g d−1) and calendar year of diagnosis (continuous).
Cox proportional hazard model adjusted for the variables above plus disease stage (I, II, III/IV), grade (I, II, III), radiation treatment (yes/no), and chemotherapy and/or hormonal treatment (no chemotherapy or hormonal treatment, hormonal therapy and no chemotherapy, chemotherapy and no hormonal therapy, and hormonal therapy and chemotherapy).