Table 1.
Baseline characteristics of participants in the SUN Project, according to energy-adjusted quartiles of vitamin D (diet and supplemented).
| Variable | Q1 | Q2 | Q3 | Q4 | p Value + |
|---|---|---|---|---|---|
| n | 4505 | 4504 | 4504 | 4504 | |
| Total vitamin D intake (µg/day) * | 2.7 (2.0–3.2) | 4.4 (4.0–4.7) | 5.8 (5.4–6.5) | 11.7 (11.0–12.5) | <0.001 |
| Age (years) | 35 (27–45) | 36 (27–46) | 35 (27–46) | 37 (28–49) | <0.001 |
| Sex (% women) | 62.1 | 59.3 | 58.4 | 59.6 | 0.003 |
| Body-mass index (kg/m2) | 22.8 (20.7–25.4) | 23.1 (20.9–25.6) | 23.1 (20.9–25.5) | 23.4 (21.0–25.9) | <0.001 |
| Height (cm) | 168 (162–174) | 168 (162–175) | 168 (162–175) | 168 (162–174) | 0.174 |
| Physical activity (METs-h/week) | 14.2 (4.2–27.5) | 14.8 (5.1–29.1) | 15.9 (5.7–29.8) | 18.9 (7.4–34.4) | <0.001 |
| Total energy intake (kcal/day) | 2517 (2048–2997) | 2362 (1976–2715) | 2041 (1682–2503) | 2358 (1975–2767) | <0.001 |
| Alcohol intake (g/day) | 2.6 (0.6–8.8) | 3.2 (0.9–8.8) | 3.1 (0.9–8.4) | 3.2 (0.9–9.0) | <0.001 |
| Sugar-sweetened beverages (servings/day) | 0.1 (0.0–0.4) | 0.1 (0.0–0.1) | 0.1 (0.0–0.1) | 0.1 (0.0–0.1) | <0.001 |
| Coffee (servings/day) | 1.0 (0.4–2.5) | 1.0 (0.4–2.5) | 1.0 (0.4–2.5) | 1.0 (0.4–2.5) | <0.001 |
| Adherence to Mediterranean Diet Score | 4 (3–5) | 4 (3–5) | 4 (3–5) | 5 (3–6) | <0.001 |
| Time of university education (years) | 5 (4–5) | 5 (4–5) | 5 (4–5) | 5 (4–5) | 0.047 |
| Smoking habit (%) | <0.001 | ||||
| Never | 47.6 | 48.7 | 50.6 | 47.7 | |
| Current | 23.8 | 22.6 | 21.5 | 20.2 | |
| Former | 28.6 | 28.7 | 27.9 | 32.1 | |
| Tobacco consumption (pack-years) | 0.5 (0.0–10.0) | 0.5 (0.0–10.0) | 0.0 (0.0–9.0) | 0.5 (0.0–11.0) | <0.001 |
| TV watching (h/day) | 1.5 (0.8–2.0) | 1.5 (0.8–2.0) | 1.4 (0.7–2.0) | 1.4 (0.8–2.0) | 0.101 |
| Solar irradiation (kWh/m2/day) | 4.0 (3.9–4.5) | 4.0 (3.7–4.6) | 4.1 (3.8–4.6) | 4.2 (3.7–4.7) | 0.192 |
| Sunlight exposure (h/year) | 1984 (1866–2816) | 1984 (1866–2822) | 1984 (1866–2887) | 2279 (1866–2887) | <0.001 |
| Family history (%) | |||||
| Breast cancer | 27.0 | 25.6 | 27.4 | 27.1 | 0.21 |
| Colorectal cancer | 14.6 | 14.6 | 15.1 | 16.3 | 0.09 |
* Values represent medians (interquartile range), unless otherwise stated. + Chi-squared test for comparisons of proportions and ANOVA test or Kruskal–Wallis test for quantitative traits.