Table 5.
Dietary selenium intake. Hazard Ratio (HR) and 95% Confidence Interval (CI) of breast cancer by tertiles of energy-adjusted dietary selenium at baseline among female participants of the SUN cohort.
| Tertiles of Energy-Adjusted of Dietary Selenium Intake | ||||
|---|---|---|---|---|
| T1 | T2 | T3 | P for Trend | |
| Overall | ||||
| Intake range, (mcg⁄d) | <80.9 | 80.9–101.1 | >101.1 | |
| Median intake, (mcg⁄d) | 69.0 | 90.5 | 114.5 | |
| No of participants | 3328 | 3328 | 3327 | |
| Person-years | 37,884 | 37,563 | 37,553 | |
| Cases | 32 | 26 | 49 | |
| Incidence rate/10,000 person-years | 8.44 | 6.92 | 13.05 | |
| Age-adjusted | 1.00 (reference) | 0.74 (0.44–1.25) | 1.26 (0.81–1.97) | 0.215 |
| Model 1 | 1.00 (reference) | 0.73 (0.43–1.23) | 1.27 (0.81–1.99) | 0.209 |
| Model 2 | 1.00 (reference) | 0.76 (0.45–1.29) | 1.37 (0.85–2.20) | 0.135 |
| Premenopausal | ||||
| Intake range, (mcg⁄d) | <80.4 | 80.4–100.3 | >100.3 | |
| Median intake, (mcg⁄d) | 68.6 | 90.1 | 113.8 | |
| No of participants | 3077 | 3077 | 3076 | |
| Person-years | 32,766 | 31,929 | 31,147 | |
| Cases | 19 | 17 | 24 | |
| Incidence rate/10,000 person-years | 5.80 | 5.32 | 7.71 | |
| Age-adjusted | 1.00 (reference) | 0.67 (0.38–1.17) | 1.18 (0.73–1.90) | 0.379 |
| Model 1 | 1.00 (reference) | 0.64 (0.36–1.13) | 1.24 (0.77–2.01) | 0.268 |
| Model 2 | 1.00 (reference) | 0.65 (0.37–1.16) | 1.29 (0.78–2.14) | 0.226 |
| Postmenopausal | ||||
| Intake range, (mcg⁄d) | < 84.5 | 84.5–105.2 | > 105.2 | |
| Median intake, (mcg⁄d) | 72.7 | 93.8 | 118.2 | |
| No of participants | 987 | 987 | 987 | |
| Person-years | 6360 | 6663 | 6988 | |
| Cases | 11 | 8 | 20 | |
| Incidence rate/10,000 person-years | 17.30 | 12.01 | 28.62 | |
| Age-adjusted | 1.00 (reference) | 0.69 (0.28–1.71) | 1.68 (0.80–3.51) | 0.106 |
| Model 1 | 1.00 (reference) | 0.64 (0.25–1.61) | 1.65 (0.78–3.48) | 0.115 |
| Model 2 | 1.00 (reference) | 0.68 (0.27–1.75) | 1.70 (0.77–3.75) | 0.118 |
Abbreviations: CI, confidence interval; HR, hazard ratio; Ref., reference. -Model 1: crude model additionally adjusted for age of menarche (four categories), age at menopause (three categories), alcohol intake (g/d, continuous), breastfeeding (months, continuous), BMI (kg/m2, continuous), height (cm, continuous), hormone replacement therapy (dichotomous) and its duration (years, continuous), obstetric history (five categories), physical activity (metabolic equivalent-h/week, continuous), relatives with history of breast cancer (three categories), smoking habit (package/year, continuous), smoking status (three categories), and years at university (continuous). For premenopausal women, models were not adjusted for age at menopause, hormone replacement therapy and its duration. For menopausal women, models were additionally adjusted for time since recruitment until the beginning of the time at risk (years, continuous). -Model 2: model 1 additionally adjusted for calcium intake (mg/d, continuous), coffee consumption (two categories), fat intake (E%, continuous), Mediterranean diet adherence (points, continuous), sugar-sweetened beverages (three categories), total energy intake (Kcal/d, continuous), TV-watching (hours/d, continuous), and use of supplements (dichotomous).