Table 8.
Distribution of sun/vitamin D behavioral variables during study, by years poststudy entry.
| Baseline | 1–1.99 years postentry | 2–2.99 years postentry | 3–3.99 years postentry | 4–4.99 years postentry | 5+ years postentry | Test for difference by Chi-square test | |
|---|---|---|---|---|---|---|---|
| Summer weekday UVR-load (kJ/m2) | |||||||
| 12–41 >41–62 >62–134 >134–422 |
76 (55.9%) 24 (17.7%) 29 (21.3%) 7 (5.2%) |
43 (32.6%) 23 (17.4%) 34 (25.8%)* 32 (24.2%)** |
16 (12.8%) 40 (32.0%)** 30 (24.0%)** 39 (31.2%)** |
15 (17.8%) 24 (22.0%)** 28 (25.7%)** 42 (38.5%)** |
10 (7.8%) 28 (21.7%)** 41 (31.8%)** 50 (38.8%)** |
7 (7.9%) 24 (27.0%)** 28 (31.5%)** 30 (33.7%)** |
p < 0.001 |
| Summer weekend UVR-load (kJ/m2) | |||||||
| 5–19 >19–50 >50–90 >90–176 |
59 (43.4%) 63 (46.3%) 9 (6.6%) 5 (3.7%) |
341 (23.5%) 47 (35.7%) 28 (21.2%)** 26 (19.7%)** |
21 (16.8%) 15 (12.0%) 47 (37.6%)** 42 (33.6%)** |
12 (11.0%) 21 (19.3%) 31 (28.4%)** 45 (41.3%)** |
18 (14.0%) 17 (13.2%) 49 (38.0%)** 45 (34.9%)** |
15 (16.9%) 8 (9.0%) 32 (36.0%)** 34 (38.2%)** |
p < 0.001 |
| Summer holiday UVR-load (kJ/m2) | |||||||
| 3–16 >16–31 >31–64 >64–103 |
58 (45.0%) 56 (43.4%) 12 (9.3%) 3 (2.3%) |
37 (28.5%) 41 (31.5%) 25 (19.2%)* 27 (20.8%)** |
20 (16.0%) 15 (12.0%) 45 (36.0%)** 45 (36.0%)** |
11 (10.2%) 19 (17.6%) 34 (31.5%)** 44 (40.7%)** |
21 (16.2%) 21 (16.2%) 49 (37.7%)** 39 (30.0%)** |
11 (12.2%) 16 (17.8%) 25 (27.8%)** 38 (42.2%)** |
p < 0.001 |
| Winter weekday UVR-load (kJ/m2) | |||||||
| 0–7 >7–17 >17–26 >26–198 |
81 (59.6%) 26 (19.1%) 12 (8.8%) 17 (12.5%) |
52 (39.4%) 20 (15.2%) 28 (21.2%)* 32 (24.2%)* |
12 (9.6%) 36 (28.8%)** 41 (32.8%)** 36 (28.8%)** |
14 (12.8%) 29 (26.6%)** 38 (34.9%)** 28 (25.7%)** |
21 (16.3%) 31 (24.0%)** 34 (26.4%)** 43 (33.3%)** |
17 (19.1%) 25 (28.1%)** 23 (25.8%)** 24 (27.0%)** |
p < 0.001 |
| Winter weekend UVR-load (kJ/m2) | |||||||
| 0–4 >4–9 >9–20 >20–121 |
58 (42.7%) 55 (40.4%) 19 (14.0%) 4 (2.9%) |
42 (31.8%) 41 (31.1%) 26 (19.7%) 23 (17.4%)** |
21 (16.8%) 25 (20.0%) 29 (23.2%)** 50 (40.0%)** |
12 (11.0%) 29 (26.6%)* 37 (33.9%)** 31 (28.4%)** |
23 (17.8%) 32 (24.8%) 37 (28.7%)** 37 (28.7%)** |
10 (11.2%) 20 (22.5%) 26 (29.2%)** 33 (37.1%)** |
p < 0.001 |
| Winter holiday UVR-load (kJ/m2) | |||||||
| 0–3 >3–6 >6–14 >14–70 |
57 (44.5%) 44 (34.4%) 22 (17.2%) 5 (3.9%) |
40 (33.1%) 35 (28.9%) 23 (19.0%)* 23 (19.0%)** |
20 (17.5%) 22 (19.3%) 24 (21.1%)** 48 (42.1%)** |
8 (7.9%) 30 (29.7%)** 34 (33.7%)* 29 (28.7%)** |
31 (24.4%) 22 (17.3%) 39 (30.7%)** 35 (27.6%)** |
12 (13.6%) 17 (19.3%) 26 (29.6%)** 33 (37.5%)** |
p < 0.001 |
| Taking vitamin D-containing supplement at review? | |||||||
| No Yes |
110 (75.9%) 35 (24.1%) |
115 (81.6%) 26 (18.4%) |
99 (75.6%) 32 (24.4%) |
73 (67.0%) 36 (33.0%) |
77 (58.8%) 54 (41.2%)* |
55 (59.8%) 37 (40.2%)* |
p < 0.001 |
| Taking high-dose (1,000 IU+) vitamin D-containing supplement at review? | |||||||
| No Yes |
143 (98.6%) 2 (1.4%) |
139 (98.6%) 2 (1.4%) |
123 (93.9%) 8 (6.1%) |
95 (87.2%) 14 (12.8%)* |
98 (74.8%) 33 (25.2%)** |
60 (65.2%) 32 (34.8%)** |
p < 0.001 |
Restricted to persons followed up to 5-year review. Test for difference of strata by review assessed by multinomial logistic regression.
Results in bold denote statistical significance (p < 0.05). Results in italics are for tests of trend.
*p < 0.05.
**p < 0.001.
UVR, ultraviolet radiation.