Table 2.
Hazard ratio (HR) and 95% confidence intervals (CI) of confirmed breast cancer cases according to the categories of baseline total dairy, whole-fat, low-fat, and fermented dairy product consumption among 10,930 women of the SUN Project.
| Total Dairy Product Consumption | |||||
| Q1 (Ref.) | Q2 | Q3 | Q4 | p for trend | |
| N | 2733 | 2732 | 2733 | 2732 | |
| Median total dairy product consumption | 1.6 | 2.5 | 3.4 | 4.8 | |
| Incident cases | 41 | 23 | 19 | 36 | |
| Person-years of follow-up | 30,609 | 30,506 | 31,368 | 30,811 | |
| Incidence rate/10,000 person-years | 13.39 | 7.53 | 6.05 | 11.68 | |
| Age-adjusted HR (95% CI) | 1.00 (Ref.) | 0.59 (0.35–0.99) | 0.45 (0.26–0.78) | 0.89(0.57–1.39) | 0.665 |
| Multivariable adjusted model 1 | 1.00 (Ref.) | 0.64 (0.37–1.09) | 0.53 (0.28–1.00) | 1.19 (0.61–2.31) | 0.496 |
| Multivariable adjusted model 2 | 1.00 (Ref.) | 0.63 (0.37–1.09) | 0.52 (0.28–0.97) * | 1.17 (0.60–2.30) | 0.523 |
| Repeated measurements | 1.00 (Ref.) | 0.49 (0.28–0.84) ** | 0.49 (0.29–0.84) ** | 0.84 (0.52–1.35) | 0.623 |
| Whole-Fat Dairy Product Consumption | |||||
| Q1 (Ref.) | Q2 | Q3 | Q4 | p for trend | |
| N | 2733 | 2732 | 2733 | 2732 | |
| Median whole-fat dairy product consumption | 0.6 | 1.19 | 1.18 | 3.1 | |
| Incident cases | 29 | 32 | 28 | 30 | |
| Person-years of follow-up | 29,397 | 29,672 | 31,367 | 32,859 | |
| Incidence rate/10,000 person-years | 9.86 | 10.78 | 8.92 | 9.12 | |
| Age-adjusted HR (95% CI) | 1.00 (Ref.) | 1.19 (0.71–1.97) | 1.01 (0.60–1.72) | 1.09 (0.65–1.83) | 0.886 |
| Multivariable adjusted model 1 | 1.00 (Ref.) | 1.27 (0.75–2.15) | 1.08 (0.62–1.88) | 1.11 (0.63–1.95) | 0.912 |
| Multivariable adjusted model 2 | 1.00 (Ref.) | 1.27 (0.75–2.15) | 1.07 (0.61–1.88) | 1.10 (0.66–1.95) | 0.915 |
| Repeated measurements | 1.00 (Ref.) | 1.27 (0.76–2.14) | 1.09 (0.63–1.87) | 1.05 (0.61–1.79) | 0.830 |
| Low-Fat Dairy Product Consumption | |||||
| Q1 (Ref.) | Q2 | Q3 | Q4 | p for trend | |
| N | 2,733 | 2732 | 2,733 | 2732 | |
| Median low-fat dairy product consumption | 0.67 | 0.68 | 1.5 | 3 | |
| Incident cases | 44 | 23 | 24 | 28 | |
| Person-years of follow-up | 33,043 | 30,357 | 29,727 | 29,727 | |
| Incidence rate/10,000 person-years | 13.31 | 7.57 | 8.07 | 9.28 | |
| Age-adjusted HR (95% CI) | 1.00 (Ref.) | 0.57 (0.34–0.95) | 0.58 (0.35–0.96) | 0.63 (0.39–1.03) | 0.113 |
| Multivariable adjusted model 1 | 1.00 (Ref.) | 0.65 (0.39–1.08) | 0.69 (0.40–1.17) | 0.80 (0.44–1.44) | 0.440 |
| Multivariable adjusted model 2 | 1.00 (Ref.) | 0.65 (0.39–1.09) | 0.69 (0.40–1.17) | 0.79 (0.44–1.44) | 0.422 |
| Repeated measurements | 1.00 (Ref.) | 0.58 (0.35–0.95) * | 0.55 (0.32–0.92) * | 0.65 (0.39–1.06) | 0.136 |
| Fermented Dairy Product Consumption | |||||
| Q1 (Ref.) | Q2 | Q3 | Q4 | p for trend | |
| N | 2733 | 2732 | 2733 | 2732 | |
| Median fermented dairy product consumption | 0.5 | 1.04 | 1.6 | 2.6 | |
| Incident cases | 30 | 29 | 33 | 27 | |
| Person-years of follow-up | 31,229 | 30,973 | 30,896 | 30,196 | |
| Incidence rate/10,000 person-years | 9.60 | 9.36 | 10.68 | 8.94 | |
| Age-adjusted HR (95% CI) | 1.00 (Ref.) | 0.99 (0.59–1.65) | 1.08 (0.66–1.78) | 0.91 (0.54–1.53) | 0.746 |
| Multivariable adjusted model 1 | 1.00 (Ref.) | 1.16 (0.68–1.96) | 1.32 (0.77–2.24) | 1.23 (0.68–2.23) | 0.522 |
| Multivariable adjusted model 2 | 1.00 (Ref.) | 1.16 (0.68–1.96) | 1.32 (0.77–2.24) | 1.23 (0.68–2.23) | 0.515 |
| Repeated measurements | 1.00 (Ref.) | 1.09 (0.65–1.85) | 1.06 (0.63–1.79) | 0.99 (0.57–1.72) | 0.841 |
* p < 0.05, ** p < 0.01. Ref., reference. Results from Cox regression models. All Cox models were stratified for age (decades) and recruitment period. Model 1 additionally adjusted for height, years at university, family history of breast cancer (none, after 45 years, or before 45 years), smoking status (never smoker, former smoker, current smoker), lifetime tobacco exposure (pack-years), physical activity (METs-h/week), TV watching (h/day), alcohol intake (g/day, continuous), BMI (<25, 25–30, ≥30), age of menarche (<10 years, 10–11 years, 12–13 years, ≥14 years), age at menopause (<50 years, ≥50 years), history of pregnancy (age <25 years and nulliparous, age ≥25 years and nulliparous, first pregnancy before 25 years, first pregnancy between 25 and 30 years of age, first pregnancy being 30 years old or older), months of breastfeeding (continuous), use of hormone replacement therapy (yes/no) and its duration (continuous), energy intake (kcal/day), energy-adjusted intake of calcium, vitamin D, and saturated fat from non-dairy products (tertiles), coffee consumption (<1, ≥1), sugar-sweetened beverage consumption (never/seldom, ≥1 serving per week), and oral contraceptives (yes/no). Model 2 additionally adjusted for Mediterranean diet adherence (score Trichopolou) (continuous). Repeated measurements were adjusted for the same variables as Model 1, using cumulative averages for all dietary variables.